What crossover for .1 of 5.1?

[Carey Carlan]

I may have to visit the movie sound group for this question.

I've been asked to make a 5.1 program source for a video from one of my
concert recordings. Creating the standard 5 tracks is not a problem. What
frequencies (crossover, rolloff rate) go into the bass track of a 5.1
recording?

I've read about 48048 sample rate recordings for video so that when the 30
fps is translated to 29.97, the audio samples correctly down to 48K.

[Arny Krueger]

"Carey Carlan" > wrote in message


> I may have to visit the movie sound group for this
> question.

> I've been asked to make a 5.1 program source for a video
> from one of my concert recordings. Creating the standard
> 5 tracks is not a problem. What frequencies (crossover,
> rolloff rate) go into the bass track of a 5.1 recording?

Nothing really.

The crossover point is set in the 80-150 Hz range by installer of the
playback system. The usual crossover slope is 12 dB/octave. On occasion the
..1 channel is reproduced as is - with no crossover at all.

It is up to you to mix things so that the pieces fit together when the
playback system does its thing.

> I've read about 48048 sample rate recordings for video so
> that when the 30 fps is translated to 29.97, the audio
> samples correctly down to 48K.

There is like a 1000:1 difference here. Might make a tiny timing difference.
IME the video editing software does any resampling automagically if it is
needed. I'm forever dropping 44.1 KHz material into my videos and the
software (usually Premiere) does the right thing.

[Chris Hornbeck]

On Tue, 04 Dec 2007 03:14:42 GMT, Carey Carlan >
wrote:

>I may have to visit the movie sound group for this question.

And let me go way out on a limb and say that there may not be
a single definitive answer. A "properly set up" 5.1 channel
home playback with have subwoofer management set to play
both the woofs from the main channels and from the LFE channel.

Very many surround receivers arrive defaulted to something
else, and so remain that way. Do you leave your woof in the
main channels, restrict it to the LFE subchannel, or some
of both?

Playback conditions are, sadly, all over the map. THX might
seem like a money-making ad(vertizing)venture except for
their efforts to corral stuff like this.


>I've been asked to make a 5.1 program source for a video from one of my
>concert recordings. Creating the standard 5 tracks is not a problem. What
>frequencies (crossover, rolloff rate) go into the bass track of a 5.1
>recording?

Others will have more definitive numbers, but you can't get too
far off base with four pole crossovers at 80Hz. The alternative
viewpoint is to leave 'em alone and the LFE track empty.

I hope I've declarified the situation sufficiently!
Much thanks, as always,

Chris Hornbeck

[William Sommerwerck]

> I've read about 48048 sample-rate recordings for video so that when the
> 30 fps is translated to 29.97, the audio samples correctly down to 48K.

That's 0.1%. The DAC will have no trouble locking onto the lower frequency
(47052 Hz) .

I have a Sony 601 which outputs an S/PDIF-format signal from a 44.056kHz
digital videotape. (Remember the PCM-F1?) My outboard DAC handled it with no
problem.

[Scott Dorsey]

Carey Carlan > wrote:
>I may have to visit the movie sound group for this question.
>
>I've been asked to make a 5.1 program source for a video from one of my
>concert recordings. Creating the standard 5 tracks is not a problem. What
>frequencies (crossover, rolloff rate) go into the bass track of a 5.1
>recording?

Whatever you want. I suggest if you don't know what it's going to be
played back on tha you don't put anything there. Remember the E in LFE
is for Effects.

>I've read about 48048 sample rate recordings for video so that when the 30
>fps is translated to 29.97, the audio samples correctly down to 48K.

Why do you care? You aren't running timecode, are you? Just get slates at
front and back, let everything run wild, and let the video guys synch it
up. It's their problem, not yours.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Carey Carlan]

(Scott Dorsey) wrote in
:

> Carey Carlan > wrote:
>>I may have to visit the movie sound group for this question.
>>
>>I've been asked to make a 5.1 program source for a video from one of
>>my concert recordings. Creating the standard 5 tracks is not a
>>problem. What frequencies (crossover, rolloff rate) go into the bass
>>track of a 5.1 recording?
>
> Whatever you want. I suggest if you don't know what it's going to be
> played back on tha you don't put anything there. Remember the E in
> LFE is for Effects.

The 32' stop on the massive organ probably qualifies more as an effect than
a musical component. I'll put that in and perhaps a touch of the bass
drum, both duplicated in the main tracks.

[Carey Carlan]

"Arny Krueger" > wrote in
:

>> I've been asked to make a 5.1 program source for a video
>> from one of my concert recordings. Creating the standard
>> 5 tracks is not a problem. What frequencies (crossover,
>> rolloff rate) go into the bass track of a 5.1 recording?
>
> Nothing really.
>
> The crossover point is set in the 80-150 Hz range by installer of the
> playback system. The usual crossover slope is 12 dB/octave. On
> occasion the .1 channel is reproduced as is - with no crossover at
> all.

Sounds like you're describing a standard subwoofer installation. Do I
understand you to say that it applies to all tracks PLUS the .1?

> It is up to you to mix things so that the pieces fit together when the
> playback system does its thing.

Sounds easier all the time.

[Carey Carlan]

Chris Hornbeck > wrote in
:

>>I may have to visit the movie sound group for this question.
>
> And let me go way out on a limb and say that there may not be
> a single definitive answer. A "properly set up" 5.1 channel
> home playback with have subwoofer management set to play
> both the woofs from the main channels and from the LFE channel.
>
> Very many surround receivers arrive defaulted to something
> else, and so remain that way. Do you leave your woof in the
> main channels, restrict it to the LFE subchannel, or some
> of both?
>
> Playback conditions are, sadly, all over the map. THX might
> seem like a money-making ad(vertizing)venture except for
> their efforts to corral stuff like this.

So it is up to the installation as to whether .1 is separate or mixed with
the LF from the main channels.

I just trying to envision a system with proper LF for the mains and a
"sensuround" piston for the .1 -- sounds like fun to build and hear if you
don't go deaf first!

[Carey Carlan]

"William Sommerwerck" > wrote in
:

>> I've read about 48048 sample-rate recordings for video so that when
>> the 30 fps is translated to 29.97, the audio samples correctly down
>> to 48K.
>
> That's 0.1%. The DAC will have no trouble locking onto the lower
> frequency (47052 Hz) .
>
> I have a Sony 601 which outputs an S/PDIF-format signal from a
> 44.056kHz digital videotape. (Remember the PCM-F1?) My outboard DAC
> handled it with no problem.

Not only do I remember, I have one. I output digitally and just pretend
it's 44.1. I suppose I could upsample for absolute pitch accuracy...

[Scott Dorsey]

Carey Carlan > wrote:
(Scott Dorsey) wrote in
:
>
>> Carey Carlan > wrote:
>>>I may have to visit the movie sound group for this question.
>>>
>>>I've been asked to make a 5.1 program source for a video from one of
>>>my concert recordings. Creating the standard 5 tracks is not a
>>>problem. What frequencies (crossover, rolloff rate) go into the bass
>>>track of a 5.1 recording?
>>
>> Whatever you want. I suggest if you don't know what it's going to be
>> played back on tha you don't put anything there. Remember the E in
>> LFE is for Effects.
>
>The 32' stop on the massive organ probably qualifies more as an effect than
>a musical component. I'll put that in and perhaps a touch of the bass
>drum, both duplicated in the main tracks.

Don't put anything in the LFE that is particularly important, because
there's a good chance it will disappear before it gets to the end user.
So the low organ stop and a little bass drum spot would seem reasonable.

It's probably reasonable to put low frequency information into the mains
and let the end user's bass management system to direct it to wherever
it really needs to go. I'm not sure what the actual chances that the
bass management will be properly configured for any given viewer, though.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Carey Carlan > wrote:
>Chris Hornbeck > wrote in
>>
>> Playback conditions are, sadly, all over the map. THX might
>> seem like a money-making ad(vertizing)venture except for
>> their efforts to corral stuff like this.
>
>So it is up to the installation as to whether .1 is separate or mixed with
>the LF from the main channels.

Right. If there is "bass management" employed, some of the LF from the
main channels will be directed to the subwoofer. If there isn't, only
the LFE channel will be directed to the sub.

Which one of these is a reasonable configuration has a lot to do with
what kind of mains are being used and how low they will go without coming
apart.

Unfortunately it is usually up to the end user to configure the system.

>I just trying to envision a system with proper LF for the mains and a
>"sensuround" piston for the .1 -- sounds like fun to build and hear if you
>don't go deaf first!

That's how the system was originally conceived, and it's what you will find
in a typical theatre installation. Three full-range speakers behind the
peforated screen, restricted bandwidth surround speakers on the sides and
rear (NOT on the ceiling), and a fairly narrowband subwoofer attached to
the LFE channel.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Geoff]

Scott Dorsey wrote:
> Don't put anything in the LFE that is particularly important, because
> there's a good chance it will disappear before it gets to the end
> user. So the low organ stop and a little bass drum spot would seem
> reasonable.
>
> It's probably reasonable to put low frequency information into the
> mains and let the end user's bass management system to direct it to
> wherever it really needs to go. I'm not sure what the actual chances
> that the bass management will be properly configured for any given
> viewer, though. --scott

Beats me why they need the extra 1.1 . Use decent speakers and you should be
able to do everything right with just 4 .

And if you want 3D, then 8.

geoff

[Chris Hornbeck]

On Wed, 5 Dec 2007 16:06:59 +1300, "geoff" >
wrote:

>Beats me why they need the extra 1.1 . Use decent speakers and you should be
>able to do everything right with just 4 .

Movies are done differently, and the 5.1 stuff comes from
the movie tradition. For movies, the dialog is put into
the center, sometimes, even most often, *only* the center.

It's the way we were raised, and it works, so it's been
kept. A movie with dialog panned would sound strange; that's
how ingrained the traditional way is.

Thanks, as always,

Chris Hornbeck

[Geoff]

Chris Hornbeck wrote:
> On Wed, 5 Dec 2007 16:06:59 +1300, "geoff" >
> wrote:
>
>> Beats me why they need the extra 1.1 . Use decent speakers and you
>> should be able to do everything right with just 4 .
>
> Movies are done differently, and the 5.1 stuff comes from
> the movie tradition. For movies, the dialog is put into
> the center, sometimes, even most often, *only* the center.

Yep I know. Silly, eh, when a character is hard left and dialogue comes out
the middle. Why not just do mono and be done with it ?!!!


> It's the way we were raised, and it works, so it's been
> kept. A movie with dialog panned would sound strange; that's
> how ingrained the traditional way is.

Ah, tradition....

geoff

[D C[_2_]]

Chris Hornbeck wrote:

>> Beats me why they need the extra 1.1 . Use decent speakers and you should be
>> able to do everything right with just 4 .
>
> Movies are done differently, and the 5.1 stuff comes from
> the movie tradition. For movies, the dialog is put into
> the center, sometimes, even most often, *only* the center.
>
> It's the way we were raised, and it works, so it's been
> kept. A movie with dialog panned would sound strange; that's
> how ingrained the traditional way is.

I have many versions of "Forbidden Planet". One of the VHS versions
employs just that - panning the dialogue depending on who is talking.

[Chris Hornbeck]

On Wed, 5 Dec 2007 17:04:11 +1300, "geoff" >
wrote:

>> Movies are done differently, and the 5.1 stuff comes from
>> the movie tradition. For movies, the dialog is put into
>> the center, sometimes, even most often, *only* the center.
>
>Yep I know. Silly, eh, when a character is hard left and dialogue comes out
>the middle. Why not just do mono and be done with it ?!!!

In a way, that's what is done (for the dialog).

Look, I'm not any kind of expert on the topic, so don't take
anything I say about it as Revealed Truth, but I have a Theory!

My Theory, and What it is, Too, is that having all the dialog
(the really important part of a narrative film) in the middle,
between our ears, has the same magical effect that mono sound
has over headphones - straight into the ol' crainium.


Also, that dinosaurs were small on one end, bigger in the middle,
then smaller on the other end. That is my theory, and what it is
too.

Thanks, as always,
Anne Elke










Chris Hornbeck

[Carey Carlan]

Chris Hornbeck > wrote in
:

> Movies are done differently, and the 5.1 stuff comes from
> the movie tradition. For movies, the dialog is put into
> the center, sometimes, even most often, *only* the center.
>
> It's the way we were raised, and it works, so it's been
> kept. A movie with dialog panned would sound strange; that's
> how ingrained the traditional way is.

There are a few spoken passages. I intend that to be all that's in the
center channel.

If I had used LCR recording for the mains I would repeat that in the video.

One last question. Can I reasonably expect the video editing software to
take my 6 WAV files and convert them to Dolby Digital or the like? Or do I
need to create the surround track before delivering the audio? If so, is
there a reasonably priced tool?

[Arny Krueger]

"Carey Carlan" > wrote in message

> "Arny Krueger" > wrote in
> :
>
>>> I've been asked to make a 5.1 program source for a video
>>> from one of my concert recordings. Creating the
>>> standard 5 tracks is not a problem. What frequencies
>>> (crossover, rolloff rate) go into the bass track of a
>>> 5.1 recording?
>>
>> Nothing really.

>> The crossover point is set in the 80-150 Hz range by
>> installer of the playback system. The usual crossover
>> slope is 12 dB/octave. On occasion the .1 channel is
>> reproduced as is - with no crossover at all.

> Sounds like you're describing a standard subwoofer
> installation. Do I understand you to say that it applies
> to all tracks PLUS the .1?

It's what the surround receivers I've checked out actually do.

>> It is up to you to mix things so that the pieces fit
>> together when the playback system does its thing.

> Sounds easier all the time.

If you say so. ;-)

[Arny Krueger]

"geoff" > wrote in message

> Scott Dorsey wrote:
>> Don't put anything in the LFE that is particularly
>> important, because there's a good chance it will
>> disappear before it gets to the end user. So the low
>> organ stop and a little bass drum spot would seem
>> reasonable. It's probably reasonable to put low frequency
>> information into the mains and let the end user's bass
>> management system to direct it to wherever it really
>> needs to go. I'm not sure what the actual chances that
>> the bass management will be properly configured for any
>> given viewer, though. --scott
>
> Beats me why they need the extra 1.1 . Use decent
> speakers and you should be able to do everything right
> with just 4 .

Having a center channel speaker can be a good idea, even with only 2
channels to reproduce.

[Scott Dorsey]

geoff > wrote:
>Scott Dorsey wrote:
>> Don't put anything in the LFE that is particularly important, because
>> there's a good chance it will disappear before it gets to the end
>> user. So the low organ stop and a little bass drum spot would seem
>> reasonable.
>>
>> It's probably reasonable to put low frequency information into the
>> mains and let the end user's bass management system to direct it to
>> wherever it really needs to go. I'm not sure what the actual chances
>> that the bass management will be properly configured for any given
>> viewer, though.
>
>Beats me why they need the extra 1.1 . Use decent speakers and you should be
>able to do everything right with just 4 .

For effects. That's why they call it LFE, Low Frequency Effects. It's not
intended for music, it's intended for making the ground shake when Godzilla
stomps on the power plant in Kanazawa.

Likewise the center front channel is ESSENTIAL in a large theatre, so the
dialogue stays centered in the stereo image.

5.1 is very specifically designed for theatre sound systems. It was never
intended for home music reproduction, and if you use it for that you have
to contend both with the issues of the format and the issues involved with
playing back music on home theatre systems.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

D C > wrote:
>Chris Hornbeck wrote:
>
>>> Beats me why they need the extra 1.1 . Use decent speakers and you should be
>>> able to do everything right with just 4 .
>>
>> Movies are done differently, and the 5.1 stuff comes from
>> the movie tradition. For movies, the dialog is put into
>> the center, sometimes, even most often, *only* the center.
>>
>> It's the way we were raised, and it works, so it's been
>> kept. A movie with dialog panned would sound strange; that's
>> how ingrained the traditional way is.
>
>I have many versions of "Forbidden Planet". One of the VHS versions
>employs just that - panning the dialogue depending on who is talking.

Panned dialogue was very popular back in the early days of stereo theatre
sound, and there were a bunch of movies done that way. Just about any of
the Cinemascope productions in the sixties had panned dialogue.

Forbidden Planet is a funny sort of exception, because it was originally
mixed in Perspecta, which had a mono track with sub-audible tones that
directed the sound to different speakers. The effect doesn't seem very
natural to me.

Panned dialogue works surprisingly well on a big screen for the folks in
the center, but seems silly on television and doesn't work so well for the
folks at the extreme sides of the auditorium.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Scott Dorsey]

Carey Carlan > wrote:
>One last question. Can I reasonably expect the video editing software to
>take my 6 WAV files and convert them to Dolby Digital or the like? Or do I
>need to create the surround track before delivering the audio? If so, is
>there a reasonably priced tool?

That's a question for the post guy. Ask him what he wants you to deliver.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[William Sommerwerck]

"Scott Dorsey" > wrote in message
...
> D C > wrote:


>> I have many versions of "Forbidden Planet". One of the VHS versions
>> employs just that - panning the dialogue depending on who is talking.

> Panned dialogue was very popular back in the early days of stereo theatre
> sound, and there were a bunch of movies done that way. Just about any of
> the Cinemascope productions in the sixties had panned dialogue.

To the best of my knowledge, the last major film with panned dialog was
Superman II.


> Forbidden Planet is a funny sort of exception, because it was originally
> mixed in Perspecta, which had a mono track with sub-audible tones that
> directed the sound to different speakers. The effect doesn't seem very
> natural to me.

I'm not sure that's correct. To the best of my understanding, it had stereo
magnetic tracks.

[Carey Carlan]

(Scott Dorsey) wrote in
:

> Carey Carlan > wrote:
>>One last question. Can I reasonably expect the video editing software
>>to take my 6 WAV files and convert them to Dolby Digital or the like?
>>Or do I need to create the surround track before delivering the audio?
>> If so, is there a reasonably priced tool?
>
> That's a question for the post guy. Ask him what he wants you to
> deliver. --scott

Turns out that the 'post guy' is a 10-time emmy winner, retired engineer
for NBC. This is getting better all the time!