My rules for digital audio

[Radium]

Hi:

Here are my rules for digital audio:

A. Whether compressed or not, the audio must be monoaural and with a
sample-rate of at least 44.1 khz.

B. The only compression allowed is WMA. No other compression format is
permitted.

C. In its uncompressed form, the audio must have a bit-resolution of at
least 16-bit

D. If compression is used, then the sample-rate of the compressed and
the uncompressed version of the audio must be the same.

E. If compression is used, the only thing that should be decreased is
the bit-resolution. The sample-rate must remain unchanged

Lets say a song that was originally recorded in stereo is given to me.
The song must to be converted to mono* via the following steps:

1. Record audio from CD [or other stereo audio source] into Wavelab,
Adobe Audition [or other audio software] into a file. For simplicity
lets call this file "Track1.wav"

2. Make a copy of Track1.wav and save the copy as "Track1B.wav"

3. Open Track1.wav and reduce the gain of its audio by 77.5%

4. Convert Track1.wav to monoaural audio

5. Save Track.1

6. Open Track1B.wav and reduce its audio gain by 50%

7. Invert the phase of the left channel of Track1B.wav

8. Convert Track1B.wav to mono

9. Save Track1B.wav

10. Create a new stereo wave file whose bit-resolution is 16-bit and
sample rate is 44.1 khz. For simplicity lets call this file
"untitled.wav"

11. Copy and paste the audio of Track1.wav into the left channel of
untitled.wav

12. Copy and paste the audio of Track1B.wave into the right channel of
untitled.wav

13. Convert untitled.wav to mono

14. Save untitled.wav

*Songs that were originally-recorded in stereo need to be converted to
mono via the above 14 steps because different sounds are recorded
differently in the L and R channels. The audio that is originally
panned to the center is significantly louder than the audio whose phase
is different in the
left & right channels. This is why, I reduce the loudness of
non-inverted stereo audio file by 77.5% [before converting it to mono].
In the stereo file whose left channel has its phase inverted, I
decrease the loudness only by 50% and then convert it to mono. Usually
-- the lead vocals, bass, and percussion are recorded identically in
both the left and right channels. The paino, chorus, guitar, and synth
pads are usually recorded differently in the left and right channel.


Regards,

Radium

[Karl Uppiano]

....and this affects me how?

[Don Pearce]

On Sat, 11 Nov 2006 06:00:41 GMT, "Karl Uppiano"
> wrote:

>...and this affects me how?
>

Now, now. That was a very good set of rules designed to ensure that
nobody will ever try to steal his music. I applaud him, in fact, for
even being interested in music while stone deaf.

d

--
Pearce Consulting
http://www.pearce.uk.com

[Laurence Payne]

On 10 Nov 2006 21:40:05 -0800, "Radium" > wrote:

>Hi:
>
>Here are my rules for digital audio:

Fine. Run along and play now.

[Radium]

Soundhaspriority wrote:
> Dont forget FLAC -- "Free Lossless Audio Codec."
> http://flac.sourceforge.net/

No thanks.

[[email protected]]

Radium wrote:
> Soundhaspriority wrote:
> > Dont forget FLAC -- "Free Lossless Audio Codec."
> > http://flac.sourceforge.net/
>
> No thanks.

Yeah, that's useful, fact-based information. Radium will
have none of that.

[Radium]

Here is the visual equivalent of the rules of my digital audio:

http://groups.google.com/group/sci.electronics.basics/browse_frm/thread/7b4d3ddc7af49b38/4759e8739e79f0e3?hl=en#4759e8739e79f0e3

I know its OT but I posted it anyway.

[Karl Uppiano]

"Radium" > wrote in message
ups.com...
> Soundhaspriority wrote:
>> Dont forget FLAC -- "Free Lossless Audio Codec."
>> http://flac.sourceforge.net/
>
> No thanks.

Oh, so you do respond. I thought your original post might have been drive-by
trolling. So -- what are your rules for, and why should I care?

Do you have a particular goal in mind? For example, someone who is
interested in high quality stereo digital audio would find your rules
completely at odds with their goal.

[Radium]

Karl Uppiano wrote:
> Do you have a particular goal in mind?

I am just expressing my thoughts on audio.

> For example, someone who is
> interested in high quality stereo digital audio would find your rules
> completely at odds with their goal.

If I am going to burn something into a CD, the software will
automatically convert it to stereo because CDs requires the audio to be
stereo. So, there you go.

Two additional steps to the 14 steps I listed in the first message of
this thread:

15. Convert untitled.wav back to stereo

16. Burn to CD!

Do you think the stereo-lovers would want this? After all, CDs requires
their audio have two channels, otherwise it is not compatible with the
CD.

[Karl Uppiano]

"Radium" > wrote in message
ups.com...
> Karl Uppiano wrote:
>> Do you have a particular goal in mind?
>
> I am just expressing my thoughts on audio.

Ok. But I prefer FLAC. What do you think of that?

>> For example, someone who is
>> interested in high quality stereo digital audio would find your rules
>> completely at odds with their goal.
>
> If I am going to burn something into a CD, the software will
> automatically convert it to stereo because CDs requires the audio to be
> stereo. So, there you go.

If it is automatic, why do I have to think about it? The software developer
has to think about it. Are your rules for the software developer?

> Two additional steps to the 14 steps I listed in the first message of
> this thread:
>
> 15. Convert untitled.wav back to stereo
>
> 16. Burn to CD!
>
> Do you think the stereo-lovers would want this? After all, CDs requires
> their audio have two channels, otherwise it is not compatible with the
> CD.

Stereo lovers probably want the original stereo, if it is available
anywhere. If they are burning a mono WAV to a CD, then sure, the software
needs to convert it. But it isn't exactly stereo, just dual mono. An equally
valid approach would be to send mono to the left channel and leave the right
channel blank. Or put a completely different program on the right channel.
That would be most efficient, but probably not compatible with stereo
headphones without a switch for left or right mono. I think the CD Audio
format actually supports a monophonic mode, but I do not think it was ever
used. I don't know if a player even has to implement it to be logo-compliant
anymore.

[Eeyore]

Radium wrote:

> Hi:
>
> Here are my rules for digital audio:

Radium, you're a lunatic.

No-one gives a damn for your roolz.

Graham

[Eeyore]

Radium wrote:

> *Songs that were originally-recorded in stereo need to be converted to
> mono via the above 14 steps because different sounds are recorded
> differently in the L and R channels. The audio that is originally
> panned to the center is significantly louder than the audio whose phase
> is different in the
> left & right channels. This is why, I reduce the loudness of
> non-inverted stereo audio file by 77.5% [before converting it to mono].
> In the stereo file whose left channel has its phase inverted, I
> decrease the loudness only by 50% and then convert it to mono. Usually
> -- the lead vocals, bass, and percussion are recorded identically in
> both the left and right channels. The paino, chorus, guitar, and synth
> pads are usually recorded differently in the left and right channel.

Funny that most ppl are happy to press the mono button then !

Graham

[Eeyore]

Radium wrote:

> Karl Uppiano wrote:
> > Do you have a particular goal in mind?
>
> I am just expressing my thoughts on audio.

If we shake you can we hear your brain rattle inside your skull ?

Graham

[Kalman Rubinson]

Sigh. I thought I had to ignore Radium only on the neuroscience
newsgroups. He is notorious.

Kal


On Sat, 11 Nov 2006 22:34:22 +0000, Eeyore
> wrote:

>
>
>Radium wrote:
>
>> Karl Uppiano wrote:
>> > Do you have a particular goal in mind?
>>
>> I am just expressing my thoughts on audio.
>
>If we shake you can we hear your brain rattle inside your skull ?
>
>Graham

[George M. Middius]

Poopie is on the rag again.

> Radium, you're a lunatic.
> No-one gives a damn for your roolz.

Could this attitude possibly be the reason you have your own personal
stalker?





--

Krooscience: The antidote to education, experience, and excellence.

[MiNe 109]

In article >,
Kalman Rubinson > wrote:

> Sigh. I thought I had to ignore Radium only on the neuroscience
> newsgroups. He is notorious.

Thanks for the info.

Stephen

[Geoff]

Radium wrote:
> Hi:
>
> Here are my rules for digital audio:
>
> A. Whether compressed or not, the audio must be monoaural and with a
> sample-rate of at least 44.1 khz.
>


We are all very pleased for you.

geoff

[Randy Yates]

"Radium" > writes:
> [...]
> 3. Open Track1.wav and reduce the gain of its audio by 77.5%

That will increase the quantization noise by approximately 13 dB.
This is a bad idea.

It is also a bad idea to attempt to "help" the codec compress your
music by this step (which I believe is your goal). A lot of smart
folks have spent a lot of time determining how to best compress two
stereo tracks and I doubt your scheme can do better.
--
% Randy Yates % "Ticket to the moon, flight leaves here today
%% Fuquay-Varina, NC % from Satellite 2"
%%% 919-577-9882 % 'Ticket To The Moon'
%%%% > % *Time*, Electric Light Orchestra
http://home.earthlink.net/~yatescr

[Karl Uppiano]

Ok, I'm going to top-post here, because my responses are inline, below. I am
still trying to understand exactly what Radium thinks these rules are
supposed to accomplish.

"Radium" > wrote in message
oups.com...
> Hi:
>
> Here are my rules for digital audio:

Digital audio for high fidelity? Elevator background music? Studio
mastering? Long distance land line telephone signals? Cellular telephone
data? I-Pod? Archiving to long-term storage? I will submit to you that each
application has remarkably different requirements (and different rules for
meeting those requirements).

> A. Whether compressed or not, the audio must be monoaural and with a
> sample-rate of at least 44.1 khz.

Why monaural? Suppose I like stereo? A sample rate of 44.1 or higher will
give you 20KHz audio bandwidth. That's nice for hi-fi listening, but may be
more than you need for "You Tube" sound tracks.

> B. The only compression allowed is WMA. No other compression format is
> permitted.

I like FLAC. What about me? You might not have been aware of this, but
everything is all about me.

> C. In its uncompressed form, the audio must have a bit-resolution of at
> least 16-bit

Okay. What about dither? Does it need to be dithered? I think it needs to be
dithered at 2/3 LSB (that's my rule).

> D. If compression is used, then the sample-rate of the compressed and
> the uncompressed version of the audio must be the same.

Even if the compressed and uncompressed versions reside in different zip
codes?

> E. If compression is used, the only thing that should be decreased is
> the bit-resolution. The sample-rate must remain unchanged

I assume that by this you mean you do not want to reduce the bit rate by
reducing the sample rate, but only by means of bit allocation using a
perceptual coder.

> Lets say a song that was originally recorded in stereo is given to me.
> The song must to be converted to mono* via the following steps:
>
> 1. Record audio from CD [or other stereo audio source] into Wavelab,
> Adobe Audition [or other audio software] into a file. For simplicity
> lets call this file "Track1.wav"
>
> 2. Make a copy of Track1.wav and save the copy as "Track1B.wav"
>
> 3. Open Track1.wav and reduce the gain of its audio by 77.5%
>
> 4. Convert Track1.wav to monoaural audio

In-phase signals from left and right channels will increase by 6dB when you
sum them. In order to avoid clipping if left and right channels are full
scale, you would need to reduce the level by 50% You said reduce *by* 77.5%,
so I assume you mean drop the level *to* 22.5%. That is too much level
reduction. On the other hand, if you meant drop the level to 77.5% that is
not enough. Besides, the "convert to mono" algorithm might scale the result
for you automatically, in which case any further level correction would be
redundant.

> 5. Save Track.1
>
> 6. Open Track1B.wav and reduce its audio gain by 50%
>
> 7. Invert the phase of the left channel of Track1B.wav
>
> 8. Convert Track1B.wav to mono

So now you have a sum channel (0.225R + 0.225L) and a difference channel
(0.5R - 0.5L).

> 9. Save Track1B.wav
>
> 10. Create a new stereo wave file whose bit-resolution is 16-bit and
> sample rate is 44.1 khz. For simplicity lets call this file
> "untitled.wav"
>
> 11. Copy and paste the audio of Track1.wav into the left channel of
> untitled.wav
>
> 12. Copy and paste the audio of Track1B.wave into the right channel of
> untitled.wav

Weird, but keep going...

> 13. Convert untitled.wav to mono

You just removed most of the left channel and flipped its phase (0.5R -
0.5L) + (0.225R + 0.225L) = (0.725R - 0.275L). The right channel is 2.1dB
lower than the original; the left channel is 11dB lower than the original,
and "upside-down".

> 14. Save untitled.wav

If it was mono you wanted, you had it at step 4. If you really wanted
(0.725R - 0.275L), you could have done that all in four steps: Reduce the
right channel by 72.5%, reduce the left channel by 27.5%, flip the phase on
the left channel, and convert to mono. Try that and see if you don't get the
identical results you got with your 14-step plan.

> *Songs that were originally-recorded in stereo need to be converted to
> mono via the above 14 steps because different sounds are recorded
> differently in the L and R channels. The audio that is originally
> panned to the center is significantly louder than the audio whose phase
> is different in the
> left & right channels. This is why, I reduce the loudness of
> non-inverted stereo audio file by 77.5% [before converting it to mono].
> In the stereo file whose left channel has its phase inverted, I
> decrease the loudness only by 50% and then convert it to mono. Usually
> -- the lead vocals, bass, and percussion are recorded identically in
> both the left and right channels. The paino, chorus, guitar, and synth
> pads are usually recorded differently in the left and right channel.

People have been mixing down to mono from stereo for 50 years or more. You
simply add the left and right channels. Listening in stereo in a room
actually does more or less the same thing too (left and right speakers
working in phase (panned to center) will sum 6dB higher in the room,
depending on the frequency, and where you're standing). Record producers mix
the stereo channels for the proper artistic balance in their professional
opinion. Mixing down to mono should not be a problem.

[Radium]

Randy Yates wrote:
> That will increase the quantization noise by approximately 13 dB.

Not as far as I can perceive.

[Radium]

Karl Uppiano wrote:
> Digital audio for high fidelity?

Digital audio for any application.

> Why monaural?

Because I want both the L and R channels to sound the same.

>Suppose I like stereo?

> A sample rate of 44.1 or higher will
> give you 20KHz audio bandwidth. That's nice for hi-fi listening, but may be
> more than you need for "You Tube" sound tracks.

Any digital audio requires 44.1 khz or higher in order to sound
pleasant. Aliasing can be a real earsore.

> Okay. What about dither? Does it need to be dithered? I think it needs to be
> dithered at 2/3 LSB (that's my rule).

No need for dither.

> Even if the compressed and uncompressed versions reside in different zip
> codes?

Of course. What do zip codes have to do with this?

> I assume that by this you mean you do not want to reduce the bit rate by
> reducing the sample rate, but only by means of bit allocation using a
> perceptual coder.

Exactly.

> In-phase signals from left and right channels will increase by 6dB when you
> sum them. In order to avoid clipping if left and right channels are full
> scale, you would need to reduce the level by 50% You said reduce *by* 77.5%,
> so I assume you mean drop the level *to* 22.5%.

You assume correctly.

> If it was mono you wanted, you had it at step 4. If you really wanted
> (0.725R - 0.275L), you could have done that all in four steps: Reduce the
> right channel by 72.5%, reduce the left channel by 27.5%, flip the phase on
> the left channel, and convert to mono. Try that and see if you don't get the
> identical results you got with your 14-step plan.

The audio that was in the center channel [lead vocal, bass,
percussions] are too loud while the audio that was in the periphery
[paino, chours, guitar, synth-pads] aren't loud enough.

> People have been mixing down to mono from stereo for 50 years or more. You
> simply add the left and right channels. Listening in stereo in a room
> actually does more or less the same thing too (left and right speakers
> working in phase (panned to center) will sum 6dB higher in the room,
> depending on the frequency, and where you're standing). Record producers mix
> the stereo channels for the proper artistic balance in their professional
> opinion. Mixing down to mono should not be a problem.

My technique usually ensures that the sounds that were originally in
the central channel are not significantly louder than the sounds that
were originally in the periphery [and visa versa].

[Karl Uppiano]

"Radium" > wrote in message
oups.com...
> Karl Uppiano wrote:
>> Digital audio for high fidelity?
>
> Digital audio for any application.

Bzzt! Nope. I will guarantee that your rules will not make any sense for
digital audio for telephony (for example). Or for my application (high
fidelity). Sorry, I would not do that to my FLAC files. My compressed
formats, where unavoidable, consist of WMA, AAC and MP3. I would not import
my files that way.

>> Why monaural?
>
> Because I want both the L and R channels to sound the same.
>
>>Suppose I like stereo?
>
>> A sample rate of 44.1 or higher will
>> give you 20KHz audio bandwidth. That's nice for hi-fi listening, but may
>> be
>> more than you need for "You Tube" sound tracks.
>
> Any digital audio requires 44.1 khz or higher in order to sound
> pleasant. Aliasing can be a real earsore.

Done right, you can sample at any frequency without aliasing. The sample
rate only affects the bandwidth you can record. While I can understand
wanting full range audio for listening to music, it would be quite
inappropriate, and a big waste of bandiwdth to use 44.1KHz for telephony
(for example).

>> Okay. What about dither? Does it need to be dithered? I think it needs to
>> be
>> dithered at 2/3 LSB (that's my rule).
>
> No need for dither.

Dither eliminates the distortion due to quantization errors present in any
digital system. I feel that there is a need for dither in high quality
applications.

>> Even if the compressed and uncompressed versions reside in different zip
>> codes?
>
> Of course. What do zip codes have to do with this?

I was being facetious. There are compressed and uncompressed versions of all
sorts of things all over the world at many different sample rates. They are
not all going to follow your rules. Perhaps I was taking you too literally.

>> I assume that by this you mean you do not want to reduce the bit rate by
>> reducing the sample rate, but only by means of bit allocation using a
>> perceptual coder.
>
> Exactly.
>
>> In-phase signals from left and right channels will increase by 6dB when
>> you
>> sum them. In order to avoid clipping if left and right channels are full
>> scale, you would need to reduce the level by 50% You said reduce *by*
>> 77.5%,
>> so I assume you mean drop the level *to* 22.5%.
>
> You assume correctly.
>
>> If it was mono you wanted, you had it at step 4. If you really wanted
>> (0.725R - 0.275L), you could have done that all in four steps: Reduce the
>> right channel by 72.5%, reduce the left channel by 27.5%, flip the phase
>> on
>> the left channel, and convert to mono. Try that and see if you don't get
>> the
>> identical results you got with your 14-step plan.
>
> The audio that was in the center channel [lead vocal, bass,
> percussions] are too loud while the audio that was in the periphery
> [paino, chours, guitar, synth-pads] aren't loud enough.

I understand what you are trying to do. My point was that you were taking a
very complicated approach to arrive at what you describe as your end result.
I further said you could get the same result in far fewer steps.

>> People have been mixing down to mono from stereo for 50 years or more.
>> You
>> simply add the left and right channels. Listening in stereo in a room
>> actually does more or less the same thing too (left and right speakers
>> working in phase (panned to center) will sum 6dB higher in the room,
>> depending on the frequency, and where you're standing). Record producers
>> mix
>> the stereo channels for the proper artistic balance in their professional
>> opinion. Mixing down to mono should not be a problem.
>
> My technique usually ensures that the sounds that were originally in
> the central channel are not significantly louder than the sounds that
> were originally in the periphery [and visa versa].

I am not convinced that your technique accomplishes that goal. I won't deny
that it will change the sound. It might even sound better to you in certain
limited cases.

I will say it a different way: There are millions of hours of AM, FM and TV
broadcasts that simply sum L + R for mono receivers. Are you saying that
everyone has got it wrong for lo these many years?

[Eeyore]

"George M. Middius" wrote:

> Poopie is on the rag again.
>
> > Radium, you're a lunatic.
> > No-one gives a damn for your roolz.
>
> Could this attitude possibly be the reason you have your own personal
> stalker?

Bertei ?

No, that's something else entirely.

Graham

[Eeyore]

Radium wrote:

> Randy Yates wrote:
> > That will increase the quantization noise by approximately 13 dB.
>
> Not as far as I can perceive.

You can't 'perceive' fact from fiction or even fantasy, so no surprise there.

Graham

[Eeyore]

Radium wrote:

> No need for dither.

CRETIN !

[mrlefty]

Who would want lossless compression when you can have lossy "wma"s !?

Have any of Radium's phase cancelled S/N reduced mono monstrosities been
posted anywhere? A listener A/B might be interesting.

mrlefty

> wrote in message
ups.com...
>
> Radium wrote:
>> Soundhaspriority wrote:
>> > Dont forget FLAC -- "Free Lossless Audio Codec."
>> > http://flac.sourceforge.net/
>>
>> No thanks.
>
> Yeah, that's useful, fact-based information. Radium will
> have none of that.
>

[Radium]

Karl Uppiano wrote:
> Are you saying that
> everyone has got it wrong for lo these many years?

Not necessarily. However, most stereo-to-mono conversion involve simply
decreasing the amplitude level by 50% and then downmixing to mono. The
problem with this, is that the stuff that was identical in both
channels is much louder than the stuff that was different in each
channel.

[Radium]

mrlefty wrote:
> Have any of Radium's phase cancelled S/N reduced mono monstrosities been
> posted anywhere? A listener A/B might be interesting.

If you have a valid email address and are interested, I can send you
some songs that have been processed via my "steps"

[Karl Uppiano]

"Radium" > wrote in message
oups.com...
> Karl Uppiano wrote:
>> Are you saying that
>> everyone has got it wrong for lo these many years?
>
> Not necessarily. However, most stereo-to-mono conversion involve simply
> decreasing the amplitude level by 50% and then downmixing to mono. The
> problem with this, is that the stuff that was identical in both
> channels is much louder than the stuff that was different in each
> channel.

Ok, well, have fun with your rules. I'm glad you're not running the
engineering standards group at the FCC or something where you could force
everyone to use them. Of course, it wouldn't be anything new, the government
making public policy having the force of law based on junk science.

[Randy Yates]

"Radium" > writes:

> Randy Yates wrote:
>> That will increase the quantization noise by approximately 13 dB.
>
> Not as far as I can perceive.

Perception and reality are two different things.
--
% Randy Yates % "How's life on earth?
%% Fuquay-Varina, NC % ... What is it worth?"
%%% 919-577-9882 % 'Mission (A World Record)',
%%%% > % *A New World Record*, ELO
http://home.earthlink.net/~yatescr

[Eeyore]

Radium wrote:

> Karl Uppiano wrote:
> > Are you saying that
> > everyone has got it wrong for lo these many years?
>
> Not necessarily. However, most stereo-to-mono conversion involve simply
> decreasing the amplitude level by 50% and then downmixing to mono. The
> problem with this, is that the stuff that was identical in both
> channels is much louder than the stuff that was different in each
> channel.

As was intended.

Graham

[Radium]

Eeyore wrote:
> As was intended.

Not if the audio I'm listening to is music

[Walt]

Kalman Rubinson wrote:

> Sigh. I thought I had to ignore Radium only on the neuroscience
> newsgroups. He is notorious.

Oh. They let their vict^H^H^H^H clients post there too?


//Walt

[Walt]

Eeyore wrote:
> Radium wrote:
>>Karl Uppiano wrote:
>>
>>>Are you saying that
>>>everyone has got it wrong for lo these many years?
>>
>>Not necessarily. However, most stereo-to-mono conversion involve simply
>>decreasing the amplitude level by 50% and then downmixing to mono. The
>>problem with this, is that the stuff that was identical in both
>>channels is much louder than the stuff that was different in each
>>channel.
>
> As was intended.

Sorry, but I've got to side with Radium here. The center channel
build-up when taking a mono sum is a real phenomenon, and *not*
desirable or intentional.

It happens because taking a voltage sum of two signals increases the
level by 6db, not 3 db as you might expect. For example, if the
original stereo recording has three singers at equal volume panned hard
left, hard right, and hard center, summing to mono will make the guy in
the center 3 db louder than the other two. It was always thus.

So, what we have with Radium is a guy who likes mono (for whatever
reason - I'm not sure I want to know), but doesn't like how most stereo
programs sum to mono. So far, so good. Unfortunately his technique
doesn't come close to solving this problem - he gets .725(R) - .275(L)
not anything approaching a mono sum. But his problem is an
understandable one. (well, the sum-to-mono center channel buildup
problem at least. I'll refrain from commenting on the others)

What to do? Get used to listening in stereo? Write a signal
processing algorithm to compute a mono sum without the center channel
buildup? (maybe this has already been done?) Perform a mono sum the old
fashioned way by jamming a pencil eraser into one of your ears?

The possibilities are endless.

//Walt

[Randy Yates]

Walt > writes:
> [...]
> For example, if the original stereo recording has three singers at
> equal volume panned hard left, hard right, and hard center, summing
> to mono will make the guy in the center 3 db louder than the other
> two.

Shouldn't he have been 3 dB softer to begin with (in the stereo mix)?
--
% Randy Yates % "The dreamer, the unwoken fool -
%% Fuquay-Varina, NC % in dreams, no pain will kiss the brow..."
%%% 919-577-9882 %
%%%% > % 'Eldorado Overture', *Eldorado*, ELO
http://home.earthlink.net/~yatescr

[Walt]

Randy Yates wrote:

> Walt > writes:
>
>>[...]
>>For example, if the original stereo recording has three singers at
>>equal volume panned hard left, hard right, and hard center, summing
>>to mono will make the guy in the center 3 db louder than the other
>>two.
>
> Shouldn't he have been 3 dB softer to begin with (in the stereo mix)?

Yes and no. In order to sound like they're all three at the same level,
the center guy would be -3db in the left channel and -3db in the right
channel.

Say for the sake of the argument that guys on the outside are recorded
at a signal level of 0 dbu (.775 volts), that would mean the guy in the
center is -3dbu or 0.54837 volts. Do a mono sum and the guys on the
outside are still at .775 volts but the guy in the middle is now at
1.09674 volts, or 3db louder.

This little anomaly comes about because loudness as we perceive it is
proportional to the *square* of the voltage. It's called "center
channel buildup" and has been around for as long as we've been doing stereo.


//Walt

[Randy Yates]

Walt > writes:

> Randy Yates wrote:
>
>> Walt > writes:
>>
>>>[...]
>>>For example, if the original stereo recording has three singers at
>>>equal volume panned hard left, hard right, and hard center, summing
>>>to mono will make the guy in the center 3 db louder than the other
>>> two.
>> Shouldn't he have been 3 dB softer to begin with (in the stereo mix)?
>
> Yes and no. In order to sound like they're all three at the same
> level, the center guy would be -3db in the left channel and -3db in
> the right channel.

Why is that? In order for a signal s(t) to be perceived at the same
power, it should be split into s(t)/2 for the left and s(t)/2 for
the right. Then at the listening position it combines into

l(t) = s(t)/2 + s(t)/2
= s(t)

Thus the center guy should be 6 dB down (1/2 voltage) to sound the
same at the listening position. No?
--
% Randy Yates % "And all that I can do
%% Fuquay-Varina, NC % is say I'm sorry,
%%% 919-577-9882 % that's the way it goes..."
%%%% > % Getting To The Point', *Balance of Power*, ELO
http://home.earthlink.net/~yatescr

[Randy Yates]

Randy Yates > writes:

> Walt > writes:
>
>> Randy Yates wrote:
>>
>>> Walt > writes:
>>>
>>>>[...]
>>>>For example, if the original stereo recording has three singers at
>>>>equal volume panned hard left, hard right, and hard center, summing
>>>>to mono will make the guy in the center 3 db louder than the other
>>>> two.
>>> Shouldn't he have been 3 dB softer to begin with (in the stereo mix)?
>>
>> Yes and no. In order to sound like they're all three at the same
>> level, the center guy would be -3db in the left channel and -3db in
>> the right channel.
>
> Why is that? In order for a signal s(t) to be perceived at the same
> power, it should be split into s(t)/2 for the left and s(t)/2 for
> the right. Then at the listening position it combines into
>
> l(t) = s(t)/2 + s(t)/2
> = s(t)
>
> Thus the center guy should be 6 dB down (1/2 voltage) to sound the
> same at the listening position. No?

I should add that I believe the 3 dB/6 dB issue comes up as follows.

Let the left and right channel signals be denotes l(t) and r(t),
respectively. Also assume that l(t) and r(t) are zero-mean,
stationary signals, E[l(t)] = E[r(t)] = 0. Let them also have identical
power: E[l^2(t)] = E[r^2(t)] = P.

What is the power in their sum? We simply compute it as follows:

Psum = E[(l(t) + r(t))^2]
= E[l^2(t)] + 2*E[l(t)r(t)] + E[r^2(t)]
= 2*P + 2*E[l(t)r(t)].

If the left and right signals are completely uncorrelated, then
E[l(t)r(t)] = 0, and the sum power is 3 dB higher than the individual
channels (2*P).

If the left and right signals are perfectly correlated, then

E[l(t)r(t)] = E[l^2(t)] = E[r^2(t)]
= P

and therefore

Psum = 2*P + 2*P
= 4*P.

In this case the sum power is 6 dB (4*P) higher.
--
% Randy Yates % "She's sweet on Wagner-I think she'd die for Beethoven.
%% Fuquay-Varina, NC % She love the way Puccini lays down a tune, and
%%% 919-577-9882 % Verdi's always creepin' from her room."
%%%% > % "Rockaria", *A New World Record*, ELO
http://home.earthlink.net/~yatescr

[Karl Uppiano]

"Walt" > wrote in message
...
> Eeyore wrote:
>> Radium wrote:
>>>Karl Uppiano wrote:
>>>
>>>>Are you saying that
>>>>everyone has got it wrong for lo these many years?
>>>
>>>Not necessarily. However, most stereo-to-mono conversion involve simply
>>>decreasing the amplitude level by 50% and then downmixing to mono. The
>>>problem with this, is that the stuff that was identical in both
>>>channels is much louder than the stuff that was different in each
>>>channel.
>>
>> As was intended.
>
> Sorry, but I've got to side with Radium here. The center channel build-up
> when taking a mono sum is a real phenomenon, and *not* desirable or
> intentional.
>
> It happens because taking a voltage sum of two signals increases the level
> by 6db, not 3 db as you might expect. For example, if the original
> stereo recording has three singers at equal volume panned hard left, hard
> right, and hard center, summing to mono will make the guy in the center 3
> db louder than the other two. It was always thus.
>
> So, what we have with Radium is a guy who likes mono (for whatever
> reason - I'm not sure I want to know), but doesn't like how most stereo
> programs sum to mono. So far, so good. Unfortunately his technique
> doesn't come close to solving this problem - he gets .725(R) - .275(L) not
> anything approaching a mono sum. But his problem is an understandable
> one. (well, the sum-to-mono center channel buildup problem at least.
> I'll refrain from commenting on the others)
>
> What to do? Get used to listening in stereo? Write a signal processing
> algorithm to compute a mono sum without the center channel buildup? (maybe
> this has already been done?) Perform a mono sum the old fashioned way by
> jamming a pencil eraser into one of your ears?
>
> The possibilities are endless.
>
> //Walt

I was thinking about this the other day, and it occurred to me that center
channel build-up is likely to be more of a problem with "fake" stereo --
multi solo tracks panned to their apparent position in the mix. A "real"
stereo performance, recorded live, with co-incident microphones probably
would not have this problem, although the performers at the center might be
louder due to their proximity to the microphone. That's probably one of the
reasons orchestras are often arranged in a semicircle.

I cannot think of a simple algebraic means to knock down the center channel,
without causing collateral damage to the un-correlated material in the left
and right channels.

[[email protected]]

Radium's "rules" are sheer made up nonsense. He may do this stuff but
there is no reason anyone else anywhere should follow suit.

[Laurence Payne]

On 14 Nov 2006 02:14:53 -0800, wrote:

> Radium's "rules" are sheer made up nonsense. He may do this stuff but
>there is no reason anyone else anywhere should follow suit.


er... I think we all knew that from his first post. Some of us are
amusing ourselves by teasing him, a few others are indulging in
willie-waving regarding their knowledge of technical jargon :-)

[Eeyore]

Walt wrote:

> Eeyore wrote:
> > Radium wrote:
> >>Karl Uppiano wrote:
> >>
> >>>Are you saying that
> >>>everyone has got it wrong for lo these many years?
> >>
> >>Not necessarily. However, most stereo-to-mono conversion involve simply
> >>decreasing the amplitude level by 50% and then downmixing to mono. The
> >>problem with this, is that the stuff that was identical in both
> >>channels is much louder than the stuff that was different in each
> >>channel.
> >
> > As was intended.
>
> Sorry, but I've got to side with Radium here. The center channel
> build-up when taking a mono sum is a real phenomenon, and *not*
> desirable or intentional.
>
> It happens because taking a voltage sum of two signals increases the
> level by 6db, not 3 db as you might expect. For example, if the
> original stereo recording has three singers at equal volume panned hard
> left, hard right, and hard center, summing to mono will make the guy in
> the center 3 db louder than the other two. It was always thus.

Blah, blah, blah blah !

Have you ever tried *listening* to the effect of traditional monoing ?

Graham

[Eeyore]

wrote:

> Radium's "rules" are sheer made up nonsense.

Radium is a babbling idiot.

See his posts in the sci hierarchy.

Graham

[Walt]

Eeyore wrote:
> Walt wrote:

>>
>> The center channel
>>build-up when taking a mono sum is a real phenomenon, and *not*
>>desirable or intentional.
>>
>>It happens because taking a voltage sum of two signals increases the
>>level by 6db, not 3 db as you might expect. For example, if the
>>original stereo recording has three singers at equal volume panned hard
>>left, hard right, and hard center, summing to mono will make the guy in
>>the center 3 db louder than the other two. It was always thus.

> Blah, blah, blah blah !
>
> Have you ever tried *listening* to the effect of traditional monoing ?


Yes, every recording I have ever made, and every live broacast I've ever
engineered. (i.e. several thousand) Plus every time I've ever listened
to a mono table radio, or pressed the "mono" button on my stereo tuner.
IOW, a *lot*.

If the stereo recording is even moderately phase coherent, it'll sound
reasonable in mono. The center channel buildup is not a huge effect,
but it's not exactly subtle either. And it can actually be seen as a
positive side effect 'cause it makes things in the center pop out a
little which helps intelligibility on the table radios & mono TV sets.

//Walt

[Randy Yates]

Walt > writes:

> And it can actually be seen as a positive side effect 'cause it
> makes things in the center pop out a little which helps
> intelligibility on the table radios & mono TV sets.

Walt,

You never responded to my other post to you on this. In a nutshell, I
think the only reason we have "center-channel buildup" is because the
mastering engineer "popped out" the center channel info a bit. I.e.,
the buildup is in the mastering engineer's hands. If the levels were
mixed so that they were correct mathematically, they would not build
up and they would not pop out.

That's my prediction based on my analysis. Do you disagree? Can you
see where my analysis is invalid?
--
% Randy Yates % "She has an IQ of 1001, she has a jumpsuit
%% Fuquay-Varina, NC % on, and she's also a telephone."
%%% 919-577-9882 %
%%%% > % 'Yours Truly, 2095', *Time*, ELO
http://home.earthlink.net/~yatescr

[Walt]

Randy Yates wrote:
> Walt > writes:
>
>>And it can actually be seen as a positive side effect 'cause it
>>makes things in the center pop out a little which helps
>>intelligibility on the table radios & mono TV sets.
>
> Walt,
>
> You never responded to my other post to you on this. In a nutshell, I
> think the only reason we have "center-channel buildup" is because the
> mastering engineer "popped out" the center channel info a bit. I.e.,
> the buildup is in the mastering engineer's hands. If the levels were
> mixed so that they were correct mathematically, they would not build
> up and they would not pop out.
>
> That's my prediction based on my analysis. Do you disagree? Can you
> see where my analysis is invalid?

Yes, I disagree. The center channel buildup is an artifact of taking a
voltage sum instead of a power sum. It happens every time you combine
stereo to mono, unless the program material was momo in the first place.
Regardless what the mastering engineer does.

Do you understand why db is calculated as follows:

db = 10Log(P1/P2)
db = 20Log(V1/V2)

Why the factor of 20 instead of 10 when using voltages instead of power?

Understand that, and you'll understand the center channel buildup:
1 watt plus 1 watt equals 2 watts, for a gain of 3 db.
1 volt plus 1 volt equals 2 volts, for a gain of 6 db.

//Walt

[Eeyore]

Walt wrote:

> Randy Yates wrote:
> > Walt > writes:
> >
> >>And it can actually be seen as a positive side effect 'cause it
> >>makes things in the center pop out a little which helps
> >>intelligibility on the table radios & mono TV sets.
> >
> > Walt,
> >
> > You never responded to my other post to you on this. In a nutshell, I
> > think the only reason we have "center-channel buildup" is because the
> > mastering engineer "popped out" the center channel info a bit. I.e.,
> > the buildup is in the mastering engineer's hands. If the levels were
> > mixed so that they were correct mathematically, they would not build
> > up and they would not pop out.
> >
> > That's my prediction based on my analysis. Do you disagree? Can you
> > see where my analysis is invalid?
>
> Yes, I disagree. The center channel buildup is an artifact of taking a
> voltage sum instead of a power sum. It happens every time you combine
> stereo to mono, unless the program material was momo in the first place.
> Regardless what the mastering engineer does.
>
> Do you understand why db is calculated as follows:
>
> db = 10Log(P1/P2)
> db = 20Log(V1/V2)
>
> Why the factor of 20 instead of 10 when using voltages instead of power?
>
> Understand that, and you'll understand the center channel buildup:
> 1 watt plus 1 watt equals 2 watts, for a gain of 3 db.
> 1 volt plus 1 volt equals 2 volts, for a gain of 6 db.

Centre channel build-up only occurs with 'pan pot stereo'. 'True' stereo doesn't
have 100% correlation between L and R so doesn't exhibit full summing for centre
material when mono'd.

Most pan pots are -4.5 dB at the centre btw so the effect is very subtle even
for pan pot mixes.

Graham

[Karl Uppiano]

> wrote in message
ups.com...
> Radium's "rules" are sheer made up nonsense. He may do this stuff but
> there is no reason anyone else anywhere should follow suit.

I kind of sensed that when he posted the rules without any context or
justification. I was just trying to see if I could extract any context or
justification. He has some, but it only exists in his own private universe,
and it seems, his private universe overlaps ours only ever so slightly.

[Walt]

Eeyore wrote:

> Centre channel build-up only occurs with 'pan pot stereo'. 'True' stereo doesn't
> have 100% correlation between L and R so doesn't exhibit full summing for centre
> material when mono'd.

It is very rare for a true stereo recording to have anything hard left
or hard right in terms of level, so the center channel buildup due to
taking a voltage sum is not as much of an issue with those recordings.
Of course there may be issues with mono sum due to phase cancellation,
which can be much more severe than the center-channel buildup that we're
discussing here.

And since the ping-pong approach to panned mono is out of fashion,
panned mono recordings don't have all that much that is hard left or
hard right, which mitigates the center channel buildup. So it's one or
two, db not the theoretical 3, which is somewhat subtle compared to the
collapse of the soundstage.


> Most pan pots are -4.5 dB at the centre btw so the effect is very subtle even
> for pan pot mixes.

Most mixes are accomplished by setting the pan pots and then adjusting
the fader to the desired loudness. If that's the approach, it doesn't
matter whether the center is -3, 0, or -4.5 or whatever. I've worked
with consoles with all the above values, and unless you are adjusting
the pan pots as part of the mix, it's pretty irrelevant.

If you are making pan pot moves as part of the mix, well then obviously
the taper of the pot is important. If it's set and forget, not so much.

//Walt

[Arny Krueger]

"Walt" > wrote in message

> Randy Yates wrote:
>> Walt > writes:
>>
>>> And it can actually be seen as a positive side effect
>>> 'cause it makes things in the center pop out a little
>>> which helps intelligibility on the table radios & mono
>>> TV sets.
>>
>> Walt,
>>
>> You never responded to my other post to you on this. In
>> a nutshell, I think the only reason we have
>> "center-channel buildup" is because the mastering
>> engineer "popped out" the center channel info a bit. I.e., the buildup is
>> in the mastering engineer's hands.
>> If the levels were mixed so that they were correct
>> mathematically, they would not build up and they would
>> not pop out. That's my prediction based on my analysis. Do you
>> disagree? Can you see where my analysis is invalid?
>
> Yes, I disagree. The center channel buildup is an
> artifact of taking a voltage sum instead of a power sum. It happens every
> time you combine stereo to mono, unless
> the program material was momo in the first place.
> Regardless what the mastering engineer does.

In practice the center channel buildup in most popular recordings is the
results of several engineering decisions.

Most pop recordings are mixed from multitrack masters where the channels are
pretty much uncorrelated.

The first person (people) to get their hands on the situation is probably
the mixdown team or person. They/he are probably going to mix mostly by
pan-potting the channels. The results of what he/they does are going to be
influenced by his preferences, the pan-pot rule implmented in his mixing
environment, and how he monitors the mixdown, whether speakers, or
headphones.

Then the mastering engineer gets ahold of the mixdown, and works in
accordance with similar tools, rules, and limitations, or not.

In the end, personal preferences are going to have a lot to do with what
happens when the recording is turned into mono by simply summing the
channels. If the recording gets any kind of distribution some attention will
probably be paid to the artistic consequences of of simply summing the
channels. Mono compatibility is a real issue for most recordings.

Therefore the concern that the recording is going to go to blazes
aesthetically, if simply mixed down to mono, may be unfounded.

[Sander deWaal]

"Arny Krueger" > said:


>In practice the center channel buildup in most popular recordings is the
>results of several engineering decisions.

>Most pop recordings are mixed from multitrack masters where the channels are
>pretty much uncorrelated.

>The first person (people) to get their hands on the situation is probably
>the mixdown team or person. They/he are probably going to mix mostly by
>pan-potting the channels. The results of what he/they does are going to be
>influenced by his preferences, the pan-pot rule implmented in his mixing
>environment, and how he monitors the mixdown, whether speakers, or
>headphones.

>Then the mastering engineer gets ahold of the mixdown, and works in
>accordance with similar tools, rules, and limitations, or not.

>In the end, personal preferences are going to have a lot to do with what
>happens when the recording is turned into mono by simply summing the
>channels. If the recording gets any kind of distribution some attention will
>probably be paid to the artistic consequences of of simply summing the
>channels. Mono compatibility is a real issue for most recordings.

>Therefore the concern that the recording is going to go to blazes
>aesthetically, if simply mixed down to mono, may be unfounded.


So you *do* know your stuff, after all.

Then what's this "hifi" babbling all about, when reproducing music in
the home?

A "True Reproduction Of A Musical Event" , captured on disk, and
feeding it through a "transparent" electronic chain into loudspeakers
that may distort 5%, and a room that resonates in all kinds of
frequencies, standing waves, knots and bellies.............

Man, your average SET amp pales in comparison.

Time to take off the blinders, and get a system that you can listen to
for hours without irritation, that's the first step.

And yes, equalizers are permitted, even fixed ones like RIAA or a tube
amp ;-)

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Walt]

Arny Krueger wrote:

>If the recording gets any kind of distribution some attention will
> probably be paid to the artistic consequences of of simply summing the
> channels. Mono compatibility is a real issue for most recordings.

Agreed. Any engineer who hasn't just fallen off the turnup truck knows
to check mono compatibility.

> Therefore the concern that the recording is going to go to blazes
> aesthetically, if simply mixed down to mono, may be unfounded.

I don't think anybody said that the recording is going to go to blazes.
The center channel buildup changes the balance of the mix by a few
db, that's all. It's a real phenomonon, but not a big deal, especially
compared to real mono-incompatibility issues. 99% of the time you shrug
and say "yup, sounds ok in mono" and move on.

Which I think I'll do at this point.

//Walt

[Arny Krueger]

"Sander deWaal" > wrote in message

> "Arny Krueger" > said:
>
>
>> In practice the center channel buildup in most popular
>> recordings is the results of several engineering
>> decisions.
>
>> Most pop recordings are mixed from multitrack masters
>> where the channels are pretty much uncorrelated.
>
>> The first person (people) to get their hands on the
>> situation is probably the mixdown team or person.
>> They/he are probably going to mix mostly by pan-potting
>> the channels. The results of what he/they does are going
>> to be influenced by his preferences, the pan-pot rule
>> implmented in his mixing environment, and how he
>> monitors the mixdown, whether speakers, or headphones.
>
>> Then the mastering engineer gets ahold of the mixdown,
>> and works in accordance with similar tools, rules, and
>> limitations, or not.
>
>> In the end, personal preferences are going to have a lot
>> to do with what happens when the recording is turned
>> into mono by simply summing the channels. If the
>> recording gets any kind of distribution some attention
>> will probably be paid to the artistic consequences of of
>> simply summing the channels. Mono compatibility is a
>> real issue for most recordings.
>
>> Therefore the concern that the recording is going to go
>> to blazes aesthetically, if simply mixed down to mono,
>> may be unfounded.

> So you *do* know your stuff, after all.

> Then what's this "hifi" babbling all about, when
> reproducing music in the home?

Sander, do you understand whatm is wrong with randomly-applied distortion?

[Arny Krueger]

"Walt" > wrote in message

> Arny Krueger wrote:
>
>> If the recording gets any kind of distribution some
>> attention will probably be paid to the artistic
>> consequences of of simply summing the channels. Mono
>> compatibility is a real issue for most recordings.
>
> Agreed. Any engineer who hasn't just fallen off the
> turnup truck knows to check mono compatibility.
>
>> Therefore the concern that the recording is going to go
>> to blazes aesthetically, if simply mixed down to mono,
>> may be unfounded.
>
> I don't think anybody said that the recording is going to
> go to blazes.

Hyperbole on my part. ;-)

> The center channel buildup changes the
> balance of the mix by a few db, that's all.

Those few dB may or may not be an artistic issue.

If you raise one singer's voice by a few dB, you can easily change a trio
into a solo with backup singers.

> It's a real phenomonon, but not a big
> deal, especially compared to real mono-incompatibility
> issues. 99% of the time you shrug and say "yup, sounds ok
> in mono" and move on.

As usual, it all depends.

[Sander deWaal]

"Arny Krueger" > said:


>Sander, do you understand whatm is wrong with randomly-applied distortion?


Apparently, I understand it better than you do.

It is not a matter of "good" or "bad", of "trVth" vs. "falsehood", it
is simply a matter of preference.

Howard uses DSPs, many others use tone controls, I use tubes in some
instances and am *intentionally* modelling a modest amount of
distortion in such a way that it sounds good to me.

And a bunch of others concede, you will note.

You will never find me saying that this is hifi.
It is myfi, and unless I twist your arm to use one of my products, it
can neither be "wrong" or "right" .


What, my dear Arns, do you think happens when you press the "menu" key
on your Yamaha 02R, go into the "eq" menu and press and twist the
knobs to your heart's content?

Now *that's* randomly applied distortion if you ask me ;-)

Using ECM8000s for serious recordings is a crime, as well as using
most other B*****er products for that purpose.

Did you ever see me attacking you for doing exactly that?


Here's an interesting test:
Burn the 3 tracks from the first post by Jacco in this thread to a CD:
http://zelfbouwaudio.nl/forum/viewtopic.php?t=2961

And report back which track you prefer, or which track has the least
distortion (if you're really into accuracy, they are both the same).

I am assuming you will not cheat and throw the entire text into
Babelfish.

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Sander deWaal]

Sander deWaal > said:


>Here's an interesting test:
>Burn the 3 tracks from the first post by Jacco in this thread to a CD:
>http://zelfbouwaudio.nl/forum/viewtopic.php?t=2961

>And report back which track you prefer, or which track has the least
>distortion (if you're really into accuracy, they are both the same).

>I am assuming you will not cheat and throw the entire text into
>Babelfish.


Umm.....sorry, you will have to register first.

Here are the direct URLs to the files:
Track 01: http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/1.wav
Track 02: http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/2.wav
Track 03: http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/3.wav

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Eeyore]

Arny Krueger wrote:

> If you raise one singer's voice by a few dB, you can easily change a trio
> into a solo with backup singers.

I can attest to that.

A lot of engineers these days have a habit of mixing the vocals down in the mix
and it drives me nuts.

When I've come across it at the local venue I sometimes get the guy to increase
the vocals by ~ 3dB. That can make all the difference.

Graham

[MiNe 109]

In article >,
Eeyore > wrote:

> Arny Krueger wrote:
>
> > If you raise one singer's voice by a few dB, you can easily change a trio
> > into a solo with backup singers.
>
> I can attest to that.

As further supported by the recordings of the Supremes.

I've read the latest hits collection was remixed as more of a vocal trio.

> A lot of engineers these days have a habit of mixing the vocals down in the
> mix and it drives me nuts.
>
> When I've come across it at the local venue I sometimes get the guy to
> increase the vocals by ~ 3dB. That can make all the difference.

Maybe they want to "draw you in" to the mix!

Stephen

[Randy Yates]

Walt > writes:

> Randy Yates wrote:
>> Walt > writes:
>>
>>>And it can actually be seen as a positive side effect 'cause it
>>>makes things in the center pop out a little which helps
>>>intelligibility on the table radios & mono TV sets.
>> Walt,
>> You never responded to my other post to you on this. In a nutshell, I
>> think the only reason we have "center-channel buildup" is because the
>> mastering engineer "popped out" the center channel info a bit. I.e.,
>> the buildup is in the mastering engineer's hands. If the levels were
>> mixed so that they were correct mathematically, they would not build
>> up and they would not pop out.
>> That's my prediction based on my analysis. Do you disagree? Can you
>> see where my analysis is invalid?
>
> Yes, I disagree. The center channel buildup is an artifact of taking
> a voltage sum instead of a power sum. It happens every time you
> combine stereo to mono, unless the program material was momo in the
> first place. Regardless what the mastering engineer does.

Walt,

According to the folks at alt.sci.physics.acoustics, the pressures of
two acoustic sources sum. This means that acoustically the signals
will sum just like they do when you add their voltages electrically.

Thus someone listening to the stereo mix should perceive the same
center channel levels as someone listening to a mono signal that was
summed electrically.

> Do you understand why db is calculated as follows:
>
> db = 10Log(P1/P2)
> db = 20Log(V1/V2)
>
> Why the factor of 20 instead of 10 when using voltages instead of power?

That is a non-sequitor. Both computations result in the same power level
in dB since V is related to P by P = V^2/R.

> Understand that, and you'll understand the center channel buildup:

I do, and no, I wouldn't.

> 1 watt plus 1 watt equals 2 watts, for a gain of 3 db.
> 1 volt plus 1 volt equals 2 volts, for a gain of 6 db.

The acoustic sum should result in 6 dB as well. The acoustic sum
is not a power sum. Thus there should be no difference in summing
electrically or acoustically.

And by the way, even a pressure sum (or voltage sum) won't result
in 6 dB gain unless the two voltages are perfectly correlated.
--
% Randy Yates % "The dreamer, the unwoken fool -
%% Fuquay-Varina, NC % in dreams, no pain will kiss the brow..."
%%% 919-577-9882 %
%%%% > % 'Eldorado Overture', *Eldorado*, ELO
http://home.earthlink.net/~yatescr

[Karl Uppiano]

> The acoustic sum should result in 6 dB as well. The acoustic sum
> is not a power sum. Thus there should be no difference in summing
> electrically or acoustically.
>
> And by the way, even a pressure sum (or voltage sum) won't result
> in 6 dB gain unless the two voltages are perfectly correlated.

With stereo speakers, if you don't like the mix, move your head to the left
or the right one wavelength. :-)

[Randy Yates]

"Karl Uppiano" > writes:

>> The acoustic sum should result in 6 dB as well. The acoustic sum
>> is not a power sum. Thus there should be no difference in summing
>> electrically or acoustically.
>>
>> And by the way, even a pressure sum (or voltage sum) won't result
>> in 6 dB gain unless the two voltages are perfectly correlated.
>
> With stereo speakers, if you don't like the mix, move your head to the left
> or the right one wavelength. :-)

True. So if this is the reason the engineer boosts center channel
material, then it has nothing to do with voltage sums versus power
sums but with listening position anomalies.
--
% Randy Yates % "Midnight, on the water...
%% Fuquay-Varina, NC % I saw... the ocean's daughter."
%%% 919-577-9882 % 'Can't Get It Out Of My Head'
%%%% > % *El Dorado*, Electric Light Orchestra
http://home.earthlink.net/~yatescr

[Karl Uppiano]

"Randy Yates" > wrote in message
...
> "Karl Uppiano" > writes:
>
>>> The acoustic sum should result in 6 dB as well. The acoustic sum
>>> is not a power sum. Thus there should be no difference in summing
>>> electrically or acoustically.
>>>
>>> And by the way, even a pressure sum (or voltage sum) won't result
>>> in 6 dB gain unless the two voltages are perfectly correlated.
>>
>> With stereo speakers, if you don't like the mix, move your head to the
>> left
>> or the right one wavelength. :-)
>
> True. So if this is the reason the engineer boosts center channel
> material, then it has nothing to do with voltage sums versus power
> sums but with listening position anomalies.

Perhaps, although I doubt an engineer could predict (and mix for) the
geometry of all possible listening environments. Moving your head left or
right by one wavelength, all joking aside, is frequency-dependent and path
dependent.

[Peter Larsen]

Randy Yates wrote:

> > Yes, I disagree. The center channel buildup is an artifact of taking
> > a voltage sum instead of a power sum. It happens every time you
> > combine stereo to mono, unless the program material was momo in the
> > first place. Regardless what the mastering engineer does.

> Walt,

> According to the folks at alt.sci.physics.acoustics, the pressures of
> two acoustic sources sum. This means that acoustically the signals
> will sum just like they do when you add their voltages electrically.

Yes in case of perfect summation, in the real world you dance for joy if
you get a summation gain of 4 dB.

> Thus someone listening to the stereo mix should perceive the same
> center channel levels as someone listening to a mono signal that was
> summed electrically.

Thus someone listening to the stereo mix will perceive the center
channel levels 2 dB lower than someone listening to a mono signal that
was summed electrically.

> % Randy Yates


Peter Larsen

[Arny Krueger]

"Sander deWaal" > wrote in message

> "Arny Krueger" > said:
>
>
>> Sander, do you understand what is wrong with
>> randomly-applied distortion?

> Apparently, I understand it better than you do.

Why?

> It is not a matter of "good" or "bad", of "trVth" vs.
> "falsehood", it is simply a matter of preference.

OK, you have a prefence for figuratively rolling the dice with sound
quality, in a game that is virtually impossible for you to win. OK, I
understand masochism.

> Howard uses DSPs, many others use tone controls,

Yes, but those are designed for fine adjustment in logical steps. Also, they
are linear, and can't generate tones that aren't already in the music.

> I use tubes in some instances and am *intentionally* modelling
> a modest amount of distortion in such a way that it
> sounds good to me.

Yes, but that's nonlinear distortion which generates aharmonic tones that
just about everybody says they don't like, when given the choice.
Furthermore, your equipment has no fine adjustments for nonlinear
distortion, you have to buy a pig in a poke and live with whatever it wants
to do in your living room.

> And a bunch of others concede, you will note.

It's strange to watch.

> You will never find me saying that this is hifi.
> It is myfi, and unless I twist your arm to use one of my
> products, it can neither be "wrong" or "right" .

Never said it was right or wrong, I just said its pretty bizarre.

> What, my dear Arns, do you think happens when you press
> the "menu" key on your Yamaha 02R, go into the "eq" menu
> and press and twist the knobs to your heart's content?

I do something that is under my control in micro-steps, and I do something
that does not add aharmonic tones to the music.

> Now *that's* randomly applied distortion if you ask me ;-)

That would no doubt be due to the fact that its all over your head. I see
that in the words you use to describe it. In many cases I'm not adding
distortion but correcting and reducing it.

> Using ECM8000s for serious recordings is a crime, as well
> as using most other B*****er products for that purpose.

That would be very irrelevant to this discussion. It's also an opinon that
not generally held. Why bring it up right now?

> Did you ever see me attacking you for doing exactly that?

It's all about fear, Sander. You're talking trash and you know it.

>
> Here's an interesting test:
> Burn the 3 tracks from the first post by Jacco in this
> thread to a CD:
> http://zelfbouwaudio.nl/forum/viewtopic.php?t=2961
>
> And report back which track you prefer, or which track
> has the least distortion (if you're really into accuracy,
> they are both the same).
>
> I am assuming you will not cheat and throw the entire
> text into Babelfish.

[Arny Krueger]

"Peter Larsen" > wrote in
message
> Randy Yates wrote:
>
>>> Yes, I disagree. The center channel buildup is an
>>> artifact of taking a voltage sum instead of a power
>>> sum. It happens every time you combine stereo to mono,
>>> unless the program material was momo in the first
>>> place. Regardless what the mastering engineer does.
>
>> Walt,
>
>> According to the folks at alt.sci.physics.acoustics, the
>> pressures of two acoustic sources sum. This means that
>> acoustically the signals will sum just like they do when
>> you add their voltages electrically.
>
> Yes in case of perfect summation, in the real world you
> dance for joy if you get a summation gain of 4 dB.
>
>> Thus someone listening to the stereo mix should perceive
>> the same center channel levels as someone listening to a
>> mono signal that was summed electrically.
>
> Thus someone listening to the stereo mix will perceive
> the center channel levels 2 dB lower than someone
> listening to a mono signal that was summed electrically.


....which is enough to mess up a good mix.

[Randy Yates]

Peter Larsen > writes:

> Randy Yates wrote:
>
>> > Yes, I disagree. The center channel buildup is an artifact of taking
>> > a voltage sum instead of a power sum. It happens every time you
>> > combine stereo to mono, unless the program material was momo in the
>> > first place. Regardless what the mastering engineer does.
>
>> Walt,
>
>> According to the folks at alt.sci.physics.acoustics, the pressures of
>> two acoustic sources sum. This means that acoustically the signals
>> will sum just like they do when you add their voltages electrically.
>
> Yes in case of perfect summation, in the real world you dance for joy if
> you get a summation gain of 4 dB.
>
>> Thus someone listening to the stereo mix should perceive the same
>> center channel levels as someone listening to a mono signal that was
>> summed electrically.
>
> Thus someone listening to the stereo mix will perceive the center
> channel levels 2 dB lower than someone listening to a mono signal that
> was summed electrically.

You mean to say that, due to any number of factors, such as room
reflections, channel imbalances, asymmetrical positioning, etc., etc.,
there will probably not be a perfect 6 dB combination?

No argument there. My entire point is that this phenomenom has
*nothing* to do with "power sums versus voltage sums."
--
% Randy Yates % "Bird, on the wing,
%% Fuquay-Varina, NC % goes floating by
%%% 919-577-9882 % but there's a teardrop in his eye..."
%%%% > % 'One Summer Dream', *Face The Music*, ELO
http://home.earthlink.net/~yatescr

[Arny Krueger]

"Sander deWaal" > wrote in message

> Sander deWaal > said:
>
>
>> Here's an interesting test:
>> Burn the 3 tracks from the first post by Jacco in this
>> thread to a CD:
>> http://zelfbouwaudio.nl/forum/viewtopic.php?t=2961
>
>> And report back which track you prefer, or which track
>> has the least distortion (if you're really into
>> accuracy, they are both the same).
>
>> I am assuming you will not cheat and throw the entire
>> text into Babelfish.
>
>
> Umm.....sorry, you will have to register first.
>
> Here are the direct URLs to the files:
> Track 01:
> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/1.wav
> Track 02:
> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/2.wav
> Track 03:
> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/3.wav

Painfully simple

First off I ABXed them to see if they even sounded different. They did. I
then compared them in pairs to see which were easiest to distinguish. The
sonic disease I heard was a combination of general mud, and a general
shapening of timbres. I listen to a fair amount of live flute and violins,
and that helped.

As a result of ABXing, I knew how the files stacked up as compared to each
other.

The form of distortion was probably mostly even order distortion, probably
of a low order.

The second file is the cleanest, the first is the dirtiest, and the third
file is somewhere in-between.

Show these files to a bunch of tube bigots, particularly SET fans, and they
will probably fall in love with the first file. Yecch!

The first file really sounds pretty nasty. The second file doesn't sound
exactly pristene, but it is the best of the bunch.

[Don Pearce]

On Thu, 16 Nov 2006 07:59:56 -0500, "Arny Krueger" >
wrote:

>"Sander deWaal" > wrote in message

>> Sander deWaal > said:
>>
>>
>>> Here's an interesting test:
>>> Burn the 3 tracks from the first post by Jacco in this
>>> thread to a CD:
>>> http://zelfbouwaudio.nl/forum/viewtopic.php?t=2961
>>
>>> And report back which track you prefer, or which track
>>> has the least distortion (if you're really into
>>> accuracy, they are both the same).
>>
>>> I am assuming you will not cheat and throw the entire
>>> text into Babelfish.
>>
>>
>> Umm.....sorry, you will have to register first.
>>
>> Here are the direct URLs to the files:
>> Track 01:
>> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/1.wav
>> Track 02:
>> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/2.wav
>> Track 03:
>> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/3.wav
>
>Painfully simple
>
>First off I ABXed them to see if they even sounded different. They did. I
>then compared them in pairs to see which were easiest to distinguish. The
>sonic disease I heard was a combination of general mud, and a general
>shapening of timbres. I listen to a fair amount of live flute and violins,
>and that helped.
>
>As a result of ABXing, I knew how the files stacked up as compared to each
>other.
>
>The form of distortion was probably mostly even order distortion, probably
>of a low order.
>
>The second file is the cleanest, the first is the dirtiest, and the third
>file is somewhere in-between.
>
>Show these files to a bunch of tube bigots, particularly SET fans, and they
>will probably fall in love with the first file. Yecch!
>
>The first file really sounds pretty nasty. The second file doesn't sound
>exactly pristene, but it is the best of the bunch.
>

Agreed 100%. Files 1 and 3 have all the sonic hallmarks of even
harmonic distortion, with number 1 almost unlistenable. That some
people actually prefer to hear music this messed up is a source of
amazement to me.

d

--
Pearce Consulting
http://www.pearce.uk.com

[Arny Krueger]

"Don Pearce" > wrote in message

> On Thu, 16 Nov 2006 07:59:56 -0500, "Arny Krueger"
> > wrote:
>
>> "Sander deWaal" > wrote in message
>>
>>> Sander deWaal > said:
>>>
>>>
>>>> Here's an interesting test:
>>>> Burn the 3 tracks from the first post by Jacco in this
>>>> thread to a CD:
>>>> http://zelfbouwaudio.nl/forum/viewtopic.php?t=2961

BTW, terribly unecessary work. I downloaded them onto a PC and auditioned
them with a PCABX program, using the PC's internal "Vinyl AC 97" audio
interface and a pair of Audio Technica ATH-A700 headphones.

>>> Here are the direct URLs to the files:
>>> Track 01:
>>> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/1.wav
>>> Track 02:
>>> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/2.wav
>>> Track 03:
>>> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/3.wav

>> Painfully simple

>> First off I ABXed them to see if they even sounded
>> different. They did. I then compared them in pairs to
>> see which were easiest to distinguish. The sonic disease
>> I heard was a combination of general mud, and a general
>> shapening of timbres. I listen to a fair amount of live
>> flute and violins, and that helped.

>> As a result of ABXing, I knew how the files stacked up
>> as compared to each other.

>> The form of distortion was probably mostly even order
>> distortion, probably of a low order.

>> The second file is the cleanest, the first is the
>> dirtiest, and the third file is somewhere in-between.

>> Show these files to a bunch of tube bigots, particularly
>> SET fans, and they will probably fall in love with the
>> first file. Yecch!

>> The first file really sounds pretty nasty. The second
>> file doesn't sound exactly pristene, but it is the best
>> of the bunch.

> Agreed 100%. Files 1 and 3 have all the sonic hallmarks
> of even harmonic distortion, with number 1 almost
> unlistenable. That some people actually prefer to hear
> music this messed up is a source of amazement to me.

I haven't heard anything as bad as file 1 since I was listening to SET amps
at HE2005.

Would there be money in adding nonlinear distortion to commercial recordings
and selling them to tube bigots? ;-)

[Sander deWaal]

"Arny Krueger" > said:


>>>>> Burn the 3 tracks from the first post by Jacco in this
>>>>> thread to a CD:
>>>>> http://zelfbouwaudio.nl/forum/viewtopic.php?t=2961


>BTW, terribly unecessary work. I downloaded them onto a PC and auditioned
>them with a PCABX program, using the PC's internal "Vinyl AC 97" audio
>interface and a pair of Audio Technica ATH-A700 headphones.


I was assuming you might have wanted to listen to the files on your
main stereo system.
In most cases, this would involve burning a CD first.

But it is irrelevant, your conclusions below are entirely correct.


>>>> Here are the direct URLs to the files:
>>>> Track 01:
>>>> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/1.wav
>>>> Track 02:
>>>> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/2.wav
>>>> Track 03:
>>>> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/3.wav


>>> Painfully simple

>>> First off I ABXed them to see if they even sounded
>>> different. They did. I then compared them in pairs to
>>> see which were easiest to distinguish. The sonic disease
>>> I heard was a combination of general mud, and a general
>>> shapening of timbres. I listen to a fair amount of live
>>> flute and violins, and that helped.

>>> As a result of ABXing, I knew how the files stacked up
>>> as compared to each other.

>>> The form of distortion was probably mostly even order
>>> distortion, probably of a low order.


Correct, 2H.


>>> The second file is the cleanest, the first is the
>>> dirtiest, and the third file is somewhere in-between.


Also correct.
The second file was unchanged, the third file had a max of 5% 2H,
the first file was modified in such a way that parts of the track
reached distortion figures of 20% 2H.


>>> Show these files to a bunch of tube bigots, particularly
>>> SET fans, and they will probably fall in love with the
>>> first file. Yecch!


Not really.
A survey showed that file 3 was preferred by most, when casually
listening

Assuming you havent' done this already, run the files through a wave
editor or something and look at the properties.

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Arny Krueger]

"Sander deWaal" > wrote in message

> "Arny Krueger" > said:
>
>
>>>>>> Burn the 3 tracks from the first post by Jacco in
>>>>>> this thread to a CD:
>>>>>> http://zelfbouwaudio.nl/forum/viewtopic.php?t=2961
>
>
>> BTW, terribly unecessary work. I downloaded them onto a
>> PC and auditioned them with a PCABX program, using the
>> PC's internal "Vinyl AC 97" audio interface and a pair
>> of Audio Technica ATH-A700 headphones.

> I was assuming you might have wanted to listen to the
> files on your main stereo system.

IME good headphones are tops for critical listening.

> In most cases, this would involve burning a CD first.

But, not for me. I have a digital link.

> But it is irrelevant, your conclusions below are entirely
> correct.

>>>>> Here are the direct URLs to the files:
>>>>> Track 01:
>>>>> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/1.wav
>>>>> Track 02:
>>>>> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/2.wav
>>>>> Track 03:
>>>>> http://amorgignitamorem.nl/Audio/5ProcentTHDexperiment/3.wav

>>>> First off I ABXed them to see if they even sounded
>>>> different. They did. I then compared them in pairs to
>>>> see which were easiest to distinguish. The sonic
>>>> disease I heard was a combination of general mud, and
>>>> a general shapening of timbres. I listen to a fair
>>>> amount of live flute and violins, and that helped.

>>>> As a result of ABXing, I knew how the files stacked up
>>>> as compared to each other.

>>>> The form of distortion was probably mostly even order
>>>> distortion, probably of a low order.

> Correct, 2H.

>>>> The second file is the cleanest, the first is the
>>>> dirtiest, and the third file is somewhere in-between.

> Also correct.


> The second file was unchanged, the third file had a max
> of 5% 2H, the first file was modified in such a way that
> parts of the track reached distortion figures of 20% 2H.

The distorted files should have almost sounded worse than they did. ;-)

>>>> Show these files to a bunch of tube bigots,
>>>> particularly SET fans, and they will probably fall in
>>>> love with the first file. Yecch!

> Not really.
> A survey showed that file 3 was preferred by most, when
> casually listening

OK, so they liked half-a-Yecch. ;-)

>run the files
> through a wave editor or something and look at the
> properties.

The files aren't all that different, visually. There are slight differences
in the residuals below 30Hz. and the more distorted files tend to have
slight extensions of some of the peaks. Not knowing for a prioiri which was
the least distorted file made that hard to interpret conclusively. ABX
listening told the story.

I'm not sure this was the worst case music to show the sonic effect that was
involved.

http://www.pcabx.com/technical/nonlinear/ Provides similar listening
opportunities. The master was 24 bits, so the page could be augmented with
24 bit test files. But, the inherent NL distortion of 16 bits is already
zero. The dynamic range of those files is about 70 dB which is very good for
a real-world recording.

I'm not sure this was the worst case music to show the sonic effect that was
involved, either. In fact I know that neither of these musical samples are
anywhere close.

[Sander deWaal]

"Arny Krueger" > said:


>I'm not sure this was the worst case music to show the sonic effect that was
>involved, either. In fact I know that neither of these musical samples are
>anywhere close.


It was just a casual experiment to see whether (untrained) people
could identify 5 % 2H reliably.

They mostly couldn't, and the majority preferred the 5% distortion
files.

I agree the choice of music was umm.....probably not the best one.

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Don Pearce]

On Thu, 16 Nov 2006 18:45:07 +0100, Sander deWaal >
wrote:

>"Arny Krueger" > said:
>
>
>>I'm not sure this was the worst case music to show the sonic effect that was
>>involved, either. In fact I know that neither of these musical samples are
>>anywhere close.
>
>
>It was just a casual experiment to see whether (untrained) people
>could identify 5 % 2H reliably.
>
>They mostly couldn't, and the majority preferred the 5% distortion
>files.
>

If the majority preferred the 5% distorted version, it is fair to say
they could identify that difference - it was the ability to articulate
the nature of the difference they that they lacked.

d

--
Pearce Consulting
http://www.pearce.uk.com

[Sander deWaal]

(Don Pearce) said:


>>It was just a casual experiment to see whether (untrained) people
>>could identify 5 % 2H reliably.

>>They mostly couldn't, and the majority preferred the 5% distortion
>>files.


>If the majority preferred the 5% distorted version, it is fair to say
>they could identify that difference - it was the ability to articulate
>the nature of the difference they that they lacked.


Thanks, that's a better way of saying what I actually meant to say.

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Arny Krueger]

"Don Pearce" > wrote in message

> On Thu, 16 Nov 2006 18:45:07 +0100, Sander deWaal
> > wrote:
>
>> "Arny Krueger" > said:
>>
>>
>>> I'm not sure this was the worst case music to show the
>>> sonic effect that was involved, either. In fact I know
>>> that neither of these musical samples are anywhere
>>> close.
>>
>>
>> It was just a casual experiment to see whether
>> (untrained) people could identify 5 % 2H reliably.

Hardly a definitive test of that.

Playing various tracks off of a CD is relatively awkward. Can be expected to
desensitize the listeners.

>> They mostly couldn't, and the majority preferred the 5%
>> distortion files.
>
> If the majority preferred the 5% distorted version, it is
> fair to say they could identify that difference - it was
> the ability to articulate the nature of the difference
> they that they lacked.

One uncontrolled variable is the real possibility that the listeners thought
they preferred the last alternative that they listened to.

There are many advantages to listening tests where the listeners can readily
switch between the alternatives at will

[Mr.T]

"Arny Krueger" > wrote in message
. ..
> Would there be money in adding nonlinear distortion to commercial
recordings
> and selling them to tube bigots? ;-)

Didn't Aphex make a business out of that decades ago?

MrT.

[Eeyore]

"Mr.T" wrote:

> "Arny Krueger" > wrote
>
> > Would there be money in adding nonlinear distortion to commercial
> > recordings and selling them to tube bigots? ;-)
>
> Didn't Aphex make a business out of that decades ago?

They didn't just sell it to toobies though.

Graham

[George M. Middius]

Poopie said:

> toobies

Do you really want ppl* to remember you as The Donkey Who Was Deathly
Afeared of Tubes?

_______________________

* Not intended as condescending




--

Krooscience: The antidote to education, experience, and excellence.

[Eeyore]

"George M. Middius" wrote:

> Poopie said:
>
> > toobies
>
> Do you really want ppl* to remember you as The Donkey Who Was Deathly
> Afeared of Tubes?

The only thing about toobs that afears me is the damn voltages used !

Graham

[Mr.T]

"Eeyore" > wrote in message
...
> > > Would there be money in adding nonlinear distortion to commercial
> > > recordings and selling them to tube bigots? ;-)
> >
> > Didn't Aphex make a business out of that decades ago?
>
> They didn't just sell it to toobies though.

Of course not, they wanted to make real money, and did. Of course there are
similar plug-ins available now for digital "mastering".
It's not just toobies that are suckers obviously.

MrT.

[Sander deWaal]

Eeyore > said:


>The only thing about toobs that afears me is the damn voltages used !


Aww, c'mon Graham, 200V with 470 uF on a preamp is less harmful than
plus and minus 100V with 100,000 uFs on a PA amp (when you grab both
PNP and NPN collectors right after switch-off, as happened to me
several times).

From there, the step to 400V is not that scary.

Hey, I'm still alive ;-))

--
"Due knot trussed yore spell chequer two fined awl miss steaks."

[Arny Krueger]

"Sander deWaal" > wrote in message

> Eeyore > said:
>
>
>> The only thing about toobs that afears me is the damn
>> voltages used !

Wise man keeps one hand in pocket, wears insulating sole shoes.

> Aww, c'mon Graham, 200V with 470 uF on a preamp is less
> harmful than plus and minus 100V with 100,000 uFs on a PA
> amp (when you grab both PNP and NPN collectors right
> after switch-off, as happened to me several times).

It is all enough to kill you.

> From there, the step to 400V is not that scary.

I've been tingled by 300vdc (those radars, and home tube projects) and 416
vac/400 Hz (radars).

> Hey, I'm still alive ;-))

Greasy skin has its moments.

[Randy Yates]

"Karl Uppiano" > writes:

> "Randy Yates" > wrote in message
> ...
>> "Karl Uppiano" > writes:
>>
>>>> The acoustic sum should result in 6 dB as well. The acoustic sum
>>>> is not a power sum. Thus there should be no difference in summing
>>>> electrically or acoustically.
>>>>
>>>> And by the way, even a pressure sum (or voltage sum) won't result
>>>> in 6 dB gain unless the two voltages are perfectly correlated.
>>>
>>> With stereo speakers, if you don't like the mix, move your head to the
>>> left
>>> or the right one wavelength. :-)
>>
>> True. So if this is the reason the engineer boosts center channel
>> material, then it has nothing to do with voltage sums versus power
>> sums but with listening position anomalies.
>
> Perhaps, although I doubt an engineer could predict (and mix for) the
> geometry of all possible listening environments. Moving your head left or
> right by one wavelength, all joking aside, is frequency-dependent and path
> dependent.

Then why *would* the center-channel material be boosted? For what reason?
--
% Randy Yates % "I met someone who looks alot like you,
%% Fuquay-Varina, NC % she does the things you do,
%%% 919-577-9882 % but she is an IBM."
%%%% > % 'Yours Truly, 2095', *Time*, ELO
http://home.earthlink.net/~yatescr

[Arny Krueger]

"Randy Yates" > wrote in message

> "Karl Uppiano" > writes:
>
>> "Randy Yates" > wrote in message
>> ...
>>> "Karl Uppiano" > writes:
>>>
>>>>> The acoustic sum should result in 6 dB as well. The
>>>>> acoustic sum is not a power sum. Thus there should be
>>>>> no difference in summing electrically or acoustically.
>>>>>
>>>>> And by the way, even a pressure sum (or voltage sum)
>>>>> won't result in 6 dB gain unless the two voltages are
>>>>> perfectly correlated.
>>>>
>>>> With stereo speakers, if you don't like the mix, move
>>>> your head to the left
>>>> or the right one wavelength. :-)
>>>
>>> True. So if this is the reason the engineer boosts
>>> center channel material, then it has nothing to do with
>>> voltage sums versus power sums but with listening
>>> position anomalies.
>>
>> Perhaps, although I doubt an engineer could predict (and
>> mix for) the geometry of all possible listening
>> environments. Moving your head left or right by one
>> wavelength, all joking aside, is frequency-dependent and
>> path dependent.
>
> Then why *would* the center-channel material be boosted?
> For what reason?

(1) Mono compatibility in the sense that the recording sounds similar when
reproduced either way.
(2) Effective listening when the listener can only hear or predominately
hears only one of the two channels. A common example relates to the driver
and passenger in an automobile with speakers that are mounted way off-center
in the car. IOW, each sits right on top of one speaker, and a good distance
from the other.

[Randy Yates]

"Arny Krueger" > writes:

> "Randy Yates" > wrote in message
>
>> "Karl Uppiano" > writes:
>>
>>> "Randy Yates" > wrote in message
>>> ...
>>>> "Karl Uppiano" > writes:
>>>>
>>>>>> The acoustic sum should result in 6 dB as well. The
>>>>>> acoustic sum is not a power sum. Thus there should be
>>>>>> no difference in summing electrically or acoustically.
>>>>>>
>>>>>> And by the way, even a pressure sum (or voltage sum)
>>>>>> won't result in 6 dB gain unless the two voltages are
>>>>>> perfectly correlated.
>>>>>
>>>>> With stereo speakers, if you don't like the mix, move
>>>>> your head to the left
>>>>> or the right one wavelength. :-)
>>>>
>>>> True. So if this is the reason the engineer boosts
>>>> center channel material, then it has nothing to do with
>>>> voltage sums versus power sums but with listening
>>>> position anomalies.
>>>
>>> Perhaps, although I doubt an engineer could predict (and
>>> mix for) the geometry of all possible listening
>>> environments. Moving your head left or right by one
>>> wavelength, all joking aside, is frequency-dependent and
>>> path dependent.
>>
>> Then why *would* the center-channel material be boosted?
>> For what reason?
>
> (1) Mono compatibility in the sense that the recording sounds similar when
> reproduced either way.

That doesn't make sense. For mono compatibility - you'd not boost,
you'd keep center-channel material 6 dB down, if your objective was to
make the mono mix sound correct. This is the exact problem we're
discussing.

> (2) Effective listening when the listener can only hear or predominately
> hears only one of the two channels. A common example relates to the driver
> and passenger in an automobile with speakers that are mounted way off-center
> in the car. IOW, each sits right on top of one speaker, and a good distance
> from the other.

That makes sense.
--
% Randy Yates % "I met someone who looks alot like you,
%% Fuquay-Varina, NC % she does the things you do,
%%% 919-577-9882 % but she is an IBM."
%%%% > % 'Yours Truly, 2095', *Time*, ELO
http://home.earthlink.net/~yatescr

[Peter Larsen]

Randy Yates wrote:

>>> Then why *would* the center-channel material be boosted?
>>> For what reason?

>> (1) Mono compatibility in the sense that the recording sounds
>> similar when
>> reproduced either way.

> That doesn't make sense. For mono compatibility - you'd not boost,
> you'd keep center-channel material 6 dB down, if your objective
> was to make the mono mix sound correct. This is the exact problem
> we're discussing.

The larger difference between stereo and mono summing thereof is what
happens to stuff that differs in phase angle between the channels,
mostly but not only the reverb and ambience. The outcome, as well as the
center-zone boost, is likely to be beneficial for the listening
situation of probable mono-listeners, as long as major phase angle
differences between channels are not a problem, which basically is a lot
more of what mono-compatibility is about.

> % Randy Yates


Peter Larsen

[Arny Krueger]

"Randy Yates" > wrote in message

> "Arny Krueger" > writes:
>
>> "Randy Yates" > wrote in message
>>

>>> Then why *would* the center-channel material be boosted?
>>> For what reason?

>> (1) Mono compatibility in the sense that the recording
>> sounds similar when reproduced either way.

> That doesn't make sense. For mono compatibility - you'd
> not boost, you'd keep center-channel material 6 dB down,
> if your objective was to make the mono mix sound correct.
> This is the exact problem we're discussing.

(1) I frequently mix multitrack (16-24 track) masters, and so my comments
are based on about 3 years of practical experience.

(2) As you increase the center channel level, you make the mix more and more
mono. 100% of center channel that is L+R = mono.

>> (2) Effective listening when the listener can only hear
>> or predominately hears only one of the two channels. A
>> common example relates to the driver and passenger in an
>> automobile with speakers that are mounted way off-center
>> in the car. IOW, each sits right on top of one speaker,
>> and a good distance from the other.

> That makes sense.

[Randy Yates]

"Arny Krueger" > writes:

> "Randy Yates" > wrote in message
>
>> "Arny Krueger" > writes:
>>
>>> "Randy Yates" > wrote in message
>>>
>
>>>> Then why *would* the center-channel material be boosted?
>>>> For what reason?
>
>>> (1) Mono compatibility in the sense that the recording
>>> sounds similar when reproduced either way.
>
>> That doesn't make sense. For mono compatibility - you'd
>> not boost, you'd keep center-channel material 6 dB down,

That was actually a mis-statement, or confusing at least.

If you have a given stereo mix, you'd simply sum if your objective is
to get the same level of center-channel material in the mono mix as
you would perceive acoustically from the stereo mix under certain
assumptions.

>> if your objective was to make the mono mix sound correct.
>> This is the exact problem we're discussing.
>
> (1) I frequently mix multitrack (16-24 track) masters, and so my comments
> are based on about 3 years of practical experience.

Don't take my comments as an assault to your experience. I'm simply
speaking logically. If the goal is to make the center channel material
in the stereo mix sound the same volume in the mono mix, you would
simply sum. That is a fact established by acoustics and mathematics,
at least as I understand it. If my understanding is flawed, then
let's discuss that; otherwise, it's a given.

There well may be other reasons that you've learned from your
experience which shows that this is not "best" in some sense, but they
have nothing to do with the first principles of acoustics and the
statistics of the signals.

> 100% of center channel that is L+R = mono.

I don't understand your statement.
--
% Randy Yates % "Rollin' and riding and slippin' and
%% Fuquay-Varina, NC % sliding, it's magic."
%%% 919-577-9882 %
%%%% > % 'Living' Thing', *A New World Record*, ELO
http://home.earthlink.net/~yatescr

[Randy Yates]

Randy Yates > writes:
> [...]
> "Arny Krueger" > writes:
>> 100% of center channel that is L+R = mono.
>
> I don't understand your statement.

Here's how I would model the situation. Let

L = C + Lp
R = C + Rp,

where Lp denotes the "phasey" information in the left channel (i.e.,
the information that is not completely correlated with the right
channel) and Rp similarly for the right channel. C is the
center-channel info that is the topic of this discussion.

Both acoustically when listening to stereo (under some assumptions,
like anechoically and with perfect symmetry) AND electrically when
summing, we obtain the following (using one receiver, which isn't
actually what's happening with our head/ears, but let's simplify):

L + R = Lp + 2C + Rp.

It is this "2C" information I would consider the center channel
information in the mono mix, but it's also the center channel
information we hear acoustically from a stereo transmission.

If there is center channel buildup, it's not from this simple
operation, since the same thing happens acoustically as
electrically. The only alternative is that there is something wrong in
the assumptions here.
--
% Randy Yates % "Rollin' and riding and slippin' and
%% Fuquay-Varina, NC % sliding, it's magic."
%%% 919-577-9882 %
%%%% > % 'Living' Thing', *A New World Record*, ELO
http://home.earthlink.net/~yatescr

[Geoff]

Randy Yates wrote:
>
> Then why *would* the center-channel material be boosted? For what
> reason?

Why *is* there a centre channel ? Is it to compensate for ****-poor
imagining of average junky FL and FR speakers ?

geoff

[Randy Yates]

"Geoff" > writes:

> Randy Yates wrote:
>>
>> Then why *would* the center-channel material be boosted? For what
>> reason?
>
> Why *is* there a centre channel ? Is it to compensate for ****-poor
> imagining of average junky FL and FR speakers ?

When I say "center-channel material" I'm not referring to a 5.1
system but to a stereo system and the signal C that is common
in both channels, i.e., the stereo signal is modeled as

L = C + Lp
R = C + Rp,

where Lp and Rp contain no completely correlated component.
--
% Randy Yates % "And all that I can do
%% Fuquay-Varina, NC % is say I'm sorry,
%%% 919-577-9882 % that's the way it goes..."
%%%% > % Getting To The Point', *Balance of Power*, ELO
http://home.earthlink.net/~yatescr