Topic by pschork

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  • pschork
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  • Registered: 27-01-2011
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Topic: Linux custom suitcase controller - alsa subdevices ignored

First, let me thank the Pianoteq team for building such and amazing piece of rock solid audio software. I've been running Pianoteq on linux x86_64 for a few months now and it has been rock solid! I've even left the same instance running for over 2 weeks with no performance problems, memory leaks etc. Absolutely awesome. Thank you.

I'm building a suitcase controller / live rig using an Atom 550, Ubuntu 10.10 x86_64, Native Instruments Audio2DJ, Fatar TP80 waterfall keyboard. The rig is designed to be used headless (no monitor) and will use midi automation to control Pianoteq.  With this setup I'm getting a performance index of 13-14.

http://i.imgur.com/lSqq3.jpg

http://i.imgur.com/QV9ld.jpg

The only issue I've run into is in utilizing all 4 channels of the Audio2Dj, a 2 subdevice, low latency usb audio interface. Pianoteq will only list the first available subdevice in the Alsa config, whereas on my MacBook, Pianoteq lists all 4 channels for the Audio2Dj (not a fair audio subsystem comparison, I know).

Here is what 'aplay -l' tells me

card 2: Audio2DJ [Audio 2 DJ], device 0: Audio 2 DJ [Audio 2 DJ]
  Subdevices: 2/2
  Subdevice #0: subdevice #0
  Subdevice #1: subdevice #1

I've tried creating virtual alsa devices that included all 4 channels, but Pianoteq will still only list the first available subdevice.

I have been able to route to all 4 channels using Jack, but Jack can be unstable and my attempts at automating channel routing post launch of Pianoteq were not rock solid - there are too many things that can go wrong in a headless environment.  I've also had Jack crash on me many a time - it is not as stable as Pianoteq IMHO.

Does anyone know of any tricks to get Pianoteq to list all Alsa subdevices? That way I could select all 4 channels, save my configuration and leave it.

Thanks,
Patrick

Reply by sawtooth

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  • sawtooth
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  • Registered: 19-05-2008
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Re: Linux custom suitcase controller - alsa subdevices ignored

Nice looking setup.

I don't use pianoteq with ALSA due to latency issues so I normally use JACK.  However, I just tried using ALSA to select additional channels but ran into some difficulties.

Alsa shows my sound card with 6 possible outputs and defaults to using channels one and two.  If I try to check Channel 3 or Channel 5 then Pianoteq unselects the entire audio device.  If I check 4 before trying to check 3 then I can select the four channels and it tends to stick when reloading.  Now, I'm not sure if this is a bug in Pianoteq or if this just has to do with my particular card but I figured I would post this here (tested on 3.6.6 20110117)

Selecting a bunch out of sequence (don't recall exactly as I was just playing around) and as I selected the final channel it unselected channel 1 which I thought was pretty strange as well so maybe the channel selection with ALSA is actually buggy.  Maybe a few other users can check it out.

Reply by johnrule

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  • johnrule
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  • Registered: 21-08-2008
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Re: Linux custom suitcase controller - alsa subdevices ignored

pschork wrote:

I'm building a suitcase controller / live rig using an Atom 550, Ubuntu 10.10 x86_64, Native Instruments Audio2DJ, Fatar TP80 waterfall keyboard.

Wow...looks heavy, but nice work!

pschork wrote:

Pianoteq will only list the first available subdevice in the Alsa config, whereas on my MacBook, Pianoteq lists all 4 channels for the Audio2Dj (not a fair audio subsystem comparison, I know).

What does any other audio software in Linux show you? If other software shows you the same configuration then it is Linux itself (i.e. recognition of the audio hardware).

[edit]

Sorry, I just re-read you post and you mention the ALSA config...

In terms of the default outputs I believe you have to set that in the ALSA configuration file...it doesn't remember by just selecting it in the ALSA gui.

JR

Last edited by johnrule (28-01-2011 14:18)