[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?

[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.

[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.

[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]

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

[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]

wrote:

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

Radium is a babbling idiot.

See his posts in the sci hierarchy.

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.

[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

[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