Minimum period size of M-Audio Delta 44?

Minimum period size of M-Audio Delta 44?

[Asbjørn Sæbø]

What is the minimum period size of the M-Audio Delta 44 soundcard when 
running under ALSA?  (I am thinking of bying such a card, but would 
prefer the attainable latency to be low.)

Asbjørn Sæbø





-------------------------------------------------------
SF.Net email is Sponsored by the Better Software Conference & EXPO
September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices
Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA
Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf

Re: Minimum period size of M-Audio Delta 44?

[Clemens Ladisch]

Asbjørn Sæbø wrote:
> What is the minimum period size of the M-Audio Delta 44 soundcard when
> running under ALSA?

The snd-ice1712 driver uses a minimum period size of 80 bytes.

> (I am thinking of bying such a card, but would prefer the
> attainable latency to be low.)

The ICE1712 chip uses 40 bytes per frame (ten channels with 32 bits),
so the minimum latency at 96 kHz would be 0.02 milliseconds.

A modern computer might actually survive 48000 PCM interrupts per
second.  ;-)


HTH
Clemens



-------------------------------------------------------
SF.Net email is Sponsored by the Better Software Conference & EXPO
September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices
Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA
Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf

Re: Minimum period size of M-Audio Delta 44?

[Asbjørn Sæbø]

On Fri, Sep 09, 2005 at 03:48:18PM +0200, Clemens Ladisch wrote:
> Asbjørn Sæbø wrote:
> > What is the minimum period size of the M-Audio Delta 44 soundcard when
> > running under ALSA?
> 
> The snd-ice1712 driver uses a minimum period size of 80 bytes.

So the period size is given in bytes, not in frames or samples?
(Well, they are of course closely coupled.)

> > (I am thinking of bying such a card, but would prefer the
> > attainable latency to be low.)
> 
> The ICE1712 chip uses 40 bytes per frame (ten channels with 32 bits),
> so the minimum latency at 96 kHz would be 0.02 milliseconds.

That should suffice ;-)

The Delta 44 is a four-channel device.  If the chip is capable of 10 
channels, what happens to the other six?

Thanks!
Asbjørn



-------------------------------------------------------
SF.Net email is Sponsored by the Better Software Conference & EXPO
September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices
Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA
Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf

Re: Minimum period size of M-Audio Delta 44?

[Takashi Iwai]

At Fri, 9 Sep 2005 16:10:31 +0200,
asbjs@stud.ntnu.no wrote:
> 
> On Fri, Sep 09, 2005 at 03:48:18PM +0200, Clemens Ladisch wrote:
> > Asbjørn Sæbø wrote:
> > > What is the minimum period size of the M-Audio Delta 44 soundcard when
> > > running under ALSA?
> > 
> > The snd-ice1712 driver uses a minimum period size of 80 bytes.
> 
> So the period size is given in bytes, not in frames or samples?
> (Well, they are of course closely coupled.)

It doesn't matter.
The number of channels and the format are fixed on ice1712.

> > > (I am thinking of bying such a card, but would prefer the
> > > attainable latency to be low.)
> > 
> > The ICE1712 chip uses 40 bytes per frame (ten channels with 32 bits),
> > so the minimum latency at 96 kHz would be 0.02 milliseconds.
> 
> That should suffice ;-)
> 
> The Delta 44 is a four-channel device.  If the chip is capable of 10 
> channels, what happens to the other six?

Two are for SPDIF.  Others are not used.


Takashi


-------------------------------------------------------
SF.Net email is Sponsored by the Better Software Conference & EXPO
September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices
Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA
Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf

Re: Minimum period size of M-Audio Delta 44?

[Asbjørn Sæbø]

On Fri, Sep 09, 2005 at 04:18:45PM +0200, Takashi Iwai wrote:

> At Fri, 9 Sep 2005 16:10:31 +0200,
> asbjs@stud.ntnu.no wrote:

> [MAudio Delta 44] 
> > So the period size is given in bytes, not in frames or samples?
> > (Well, they are of course closely coupled.)
> 
> It doesn't matter.
> The number of channels and the format are fixed on ice1712.


> > The Delta 44 is a four-channel device.  If the chip is capable of 10 
> > channels, what happens to the other six?
> 
> Two are for SPDIF.  Others are not used.


OK.  Thanks for the info.

Asbjørn



-------------------------------------------------------
SF.Net email is Sponsored by the Better Software Conference & EXPO
September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices
Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA
Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf