Forums > MaxMSP

adstatus and sample size: where?

December 21, 2006 | 6:20 pm

Hello,

In adstatus, I don’t find any argument to report and control the
sample size (16bit, 24bit) of Mac OS X "Built-in Audio".
Is it well-hidden or do I have to set it manually in Audio Setup?

Philippe


December 28, 2006 | 1:01 am

If nobody knows, I guess I have to set it up directly in Audio Setup, correct?


December 28, 2006 | 8:26 am

Open the Audio Status patch and copy and paste what you need from it.

:-)

Trond

Philippe Gruchet wrote:
> If nobody knows, I guess I have to set it up directly in Audio Setup, correct?


December 28, 2006 | 11:25 pm

Trond Lossius wrote on Thu, 28 December 2006 09:26
—————————————————-
> Open the Audio Status patch and copy and paste what you need from
> it.
> :-)

I’d like to! ;-)
There’s nothing in DSP Status to directly setting up the sample size of Built-in Audio.
"Sampling Rate" works fine: any change from Max is automatically displayed in Apple’s "Audio Setup". (1 second later, or 2)
There’s nothing to perform a same task for the sample (or sampling) size: 2ca-16bit < --> 2ca-24bit.
And I really need that when testing some patchers.

Feature request?

Best wishes,
Philippe


December 29, 2006 | 2:46 am

> "Sampling Rate" works fine: any change from Max is automatically displayed in Apple’s "Audio Setup". (1 second later, or 2)
> There’s nothing to perform a same task for the sample (or sampling) size: 2ca-16bit < --> 2ca-24bit.
> And I really need that when testing some patchers.
>
> Feature request?
>
> Best wishes,
> Philippe

excuse me if am ignorant or wrong, but in most cases
24-bit interfaces do not allow to operate in 16 bit mode.

if the chosen hardware driver dos not allow this, you can
set it up like this in an app like max.

-110


December 29, 2006 | 3:30 am

Roman,

> excuse me if am ignorant or wrong, but in most cases
> 24-bit interfaces do not allow to operate in 16 bit mode.

Depends.
Ditto for the sampling rate.
And the sampling rate can be reported in [adstatus sr], not the sampling size.
"Built-in Audio" allows 32, 44.1 and 48 kHz, 16 or 24 bit for these three sampling rates.
If you’re on Mac, let’s see by yourself in Apple’s "Audio MIDI Setup", based on a Texas Instruments soundcard.

> if the chosen hardware driver does not allow this, you can
> set it up like this in an app like max.

You probably meant ‘you can’t’.
Even if we can’t change the sample size, adstatus could report the current value.
With Built-in Audio, adstatus could also control the current value.

I’m asking for this feature because when doing some FFT processing, 48kHz/24bit runs faster than 44.1kHz/16bit.
Around 15-20% faster.

Regards,
Philippe


December 29, 2006 | 7:27 am

MSP is using float representation internally, so any 16bit/24bit
differences would only make a difference when converting back and forth
between digital and analog signals in adc~, dac~, etc. AFAIK 32 bit
floating point representation on both OSX and XP use 24 bits for the
mantissa.

My guess would be that if the sound card supports 24 bits, MSP will use
that. To emulate the sound of a 16 bit card you could use degrade~ after
adc~ and before dac~, but I would be very surprised if you managed to
see this having an effect on the CPU usage of FFT. If you have
experienced differences with FFT CPU load in other applications I
suspect that it is more a question of what the overload is when
converting to/from required floating point representation before and
after the FFT calculation. Maybe this is the case in ProTools, it used
to do processing on int instead of float. I don’t know if that has
changed in the later years.

Best,
Trond

Philippe Gruchet wrote:
>> excuse me if am ignorant or wrong, but in most cases
>> 24-bit interfaces do not allow to operate in 16 bit mode.
>>
>
> Depends.
> Ditto for the sampling rate.
> And the sampling rate can be reported in [adstatus sr], not the sampling size.
> "Built-in Audio" allows 32, 44.1 and 48 kHz, 16 or 24 bit for these three sampling rates.
> If you’re on Mac, let’s see by yourself in Apple’s "Audio MIDI Setup", based on a Texas Instruments soundcard.
>
>> if the chosen hardware driver does not allow this, you can
>> set it up like this in an app like max.
>>
>
> You probably meant ‘you can’t’.
> Even if we can’t change the sample size, adstatus could report the current value.
> With Built-in Audio, adstatus could also control the current value.
>
> I’m asking for this feature because when doing some FFT processing, 48kHz/24bit runs faster than 44.1kHz/16bit.
> Around 15-20% faster.
>
> Regards,
> Philippe


December 29, 2006 | 10:59 am

Quote: Trond Lossius wrote on Fri, 29 December 2006 08:27
—————————————————-
> My guess would be that if the sound card supports 24 bits, MSP
> will use that.

Yes, it does.
About the CPU load, it seems to stay at 7%, 16 or 24 bit.
When playing a guitar pitch-shifted in gizmo~ , I clearly hear a lower latency at 48kHz-24bit than at 16bit: around -10%.
I just used the "latency-test.pat" and it confirmed what I heard.

So, I looked for this setting in [adstatus]…

Best,
Philippe


December 30, 2006 | 5:56 pm

Philippe Gruchet wrote:
> I’m asking for this feature because when doing some FFT processing,
> 48kHz/24bit runs faster than 44.1kHz/16bit. Around 15-20% faster.

Max is always using 32-bit floating point. I don’t know from where your
figures come from… Must be an illusion… Or maybe a programm which
converts after processing and that accounts for the additional time…

Philippe Gruchet wrote:
> Yes, it does. About the CPU load, it seems to stay at 7%, 16 or 24
> bit. When playing a guitar pitch-shifted in gizmo~ , I clearly hear a
> lower latency at 48kHz-24bit than at 16bit: around -10%. I just used
> the "latency-test.pat" and it confirmed what I heard.

This is exactly the difference in the sample rate between 44.1 and 48
kHz… The CPU should be higher though…

Stefan


Stefan Tiedje————x——-
–_____———–|————–
–(_|_ —-|—–|—–()——-
– _|_)—-|—–()————–
———-()——–www.ccmix.com


December 30, 2006 | 11:25 pm

Hi Stefan!
—————————————————-
> This is exactly the difference in the sample rate between 44.1
> and 48kHz…

Yes!
I just tracked the latency through gizmo~ and "Built-in Audio":
4092 samples = 85.25 ms at 48 khz/24 bits
4092 samples = 92.79 ms at 44.1 khz/24 bits
4092 samples = 127.875 ms at 32 khz/24 bits

At 16 bits, I got a higher latency, around +10%.

> The CPU should be higher though…

Ah, probably. I’ll check again with new tests.

Could I get better results at 96 khz with a good audio interface?

Thanks for your insight!

Regards,
Philippe


December 31, 2006 | 12:13 am


December 31, 2006 | 12:38 am


December 31, 2006 | 10:02 am


December 31, 2006 | 11:10 am


December 31, 2006 | 3:43 pm


December 31, 2006 | 4:42 pm


December 31, 2006 | 4:57 pm


December 31, 2006 | 5:17 pm


December 31, 2006 | 5:29 pm


January 1, 2007 | 8:58 pm

Philippe Gruchet wrote:
> At 16 bits, I got a higher latency, around +10%.

How do you switch gizmo~ from 24-bit to 16-bit? I’d try it in 32-bit
should be faster then… ;-)

If your interface (which?) does add latency, keep it in its highest
resolution always, just don’t bother with anything else… (never!)

Stefan


Stefan Tiedje————x——-
–_____———–|————–
–(_|_ —-|—–|—–()——-
– _|_)—-|—–()————–
———-()——–www.ccmix.com


January 2, 2007 | 12:16 am

Quote: Stefan Tiedje wrote on Mon, 01 January 2007 21:58
—————————————————-
> > At 16 bits, I got a higher latency, around +10%.
>
> How do you switch gizmo~ from 24-bit to 16-bit? I’d try it in
> 32-bit should be faster then… ;-)
> If your interface (which?) does add latency, keep it in its
> highest resolution always, just don’t bother with anything
> else… (never!)

I just switch the whole built-in Apple’s soundcard in the "Audio Midi Setup" application.
OMM, I just have 16 or 24-bit, not 96-bit, at 32k, 44.1k or 48kHz. No less, no more.
I think I’m going to pick up another interface this week, 96-kHz/24-bit or even 32-bit. The RME Fireface 400 seems a good candidate.

Thanks a lot Stefan and Jean-Charles!

Best wishes for 2007 ;-)
Philippe


January 2, 2007 | 1:48 am

> Depends.
> Ditto for the sampling rate.
> And the sampling rate can be reported in [adstatus sr], not the sampling size.
> "Built-in Audio" allows 32, 44.1 and 48 kHz, 16 or 24 bit for these three sampling rates.

are you sure that is the actual hw converter setting, an
not the data resolution (sent to coreaudio) when recording?


January 2, 2007 | 2:18 am

Hi Roman!

That’s what I was thinking first: the recording settings.
I’m not sure, but it seems this is applied to the whole hardware AD/DA converters.
Otherwise, I didn’t get so much latency discrepancies.

To be continued ;-)
Philippe


January 6, 2007 | 4:42 am

Hi,

(Not a hype, just a research I did for myself from this thread.)
For people reading French, a good and impartial online review about the RME Fireface 400 at AudioFanzine:

http://tinyurl.com/ykppdw

Bye,
Philippe


January 7, 2007 | 8:46 pm

Quote: Philippe Gruchet wrote on Mon, 01 January 2007 19:18
—————————————————-
> Hi Roman!
>
> That’s what I was thinking first: the recording settings.
> I’m not sure, but it seems this is applied to the whole hardware AD/DA converters.
> Otherwise, I didn’t get so much latency discrepancies.

no … you are still on the wrong path. :)

even if your built-in audio hardware could operate
in 16 AND 24 bit mode, that there is a setting for
32 bit too indicates that this is definetlay not
the hardware setting … because there is no 32 bit
audio IO hardware.
that setting is simply a conversion to coreaudio,
which is irrelevant in MAX/MSP (as well as in quicktime
player)

then, what got resolution to do with latency? normally, nothing.


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