How To Determine Soundcards Bit Depth-- 24 or 16

[sconarid]

Hello,
I recently made the transition to Linux (Fedora 16) for audio. I'm using a Lexicon Omega and everything is going well. I am able to record in Ardour without latency issues. Jack recognizes my interface. The one thing I'm not sure how to do is to verify that my interface is set to 24-bit or to verify which bit depth it's currently at. Nor would I know how to change bit depth. I've been babied by Windows, so I'm still learning my way through Linux commands. I have tried lsusb and lsusb -v, but either I missed bit depth settings, or I'm not using the correct commands. I've been googling for info---none acquired. Any help or direction will be much appreciated.
Thanks

[warkus]

Hi there Sconarid, I have a lexicon lambda which always records at 24-bit.
There is a setting "force 16-bit" in qjackctl, I am unsure whether jack is truncating 24-bits down to 16-bits, or if jack is able to set the bit depth of devices with chip sets supported by ALSA. The latter seems more likely and would yield better quality of sound at 16-bits not that i ever record at 16-bits anyway.
May i suggest that you try the "force 16-bits" (i assume it does as the name implies) record something and then again without the option, it may not be very apparent depending on what and how you record. But if your omega is only putting out 16 bits then the 24 bit file should sound exactly the same as the 16 bit file, as the last 8 bits of the 24 bit file will be empty (if your omega is only putting out 16).
I doubt that this is the case, as my lambda defaults to 24-bits but that is one way of finding out without having lexicon drivers for linux.

[Capoeira]

jack shows it when starting. in qjackctl's info window f.e. I got:

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ALSA: final selected sample format for capture: 24bit little-endian

[sconarid]

Thanks, Gentlemen,
I appreciate the responses.
@ Capoeira--- I changed jack message to verbose and was able to see the same info--24bit little-endian. Exactly what Iwas looking for, so thanks again.

Also, I noticed I'm using jack 1. Any good reason to change to jack2? I'm using Fedora's stock install, and so far, jack1 seems to be doing the job---a few crashes every now and again, but that is probably more user error than anything.

[sconarid]

Also, I noticed I'm using jack 1. Any good reason to change to jack2? I'm using Fedora's stock install, and so far, jack1 seems to be doing the job---a few crashes every now and again, but that is probably more user error than anything.

Nevermind that question. I guess it is jack2 that I have installed. Oh well. I'll keep whichever version I have since it works.

[Pablo]

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I guess it is jack2 that I have installed. Oh well. I'll keep whichever version I have since it works.

Good point. However, if you are curious
In a terminal:

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jackd --version

jackdmp 1.9.x is jack2
jackd 0.xxx.x is jack1

The differences between jack1 and jack2 are explained here:

http://trac.jackaudio.org/wiki/Q_differenc_jack1_jack2

An abstract:

So, why would I choose one or the other? For most folks, it doesn't matter.

It is a interesting reading anyway.

Cheers, Pablo

[sconarid]

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jackd --version

jackdmp 1.9.x is jack2
jackd 0.xxx.x is jack1

.

Thanks for the tip.

It is a interesting reading anyway.

Cheers, Pablo

Yeah, I saw Jack 1.9.8 and assumed "There's a 1, it must be Jack1". I'm learning that with Linux it's best not to assume anything, which is a good lesson to learn.
Thanks again.
---Scott