[PD] audio output AND input with the Rpi?

Wed Oct 30 01:58:24 CET 2013

There's good info on http://puredata.info/docs/raspberry-pi covering this,
if you haven't seen it.

There seem to be a limited number of interfaces that work.  And some people
have to slow down the USB port to get clean audio (myself included, using
the iMic (
http://www.amazon.com/Griffin-Technology-iMic-Audio-Device/dp/B000BVV2IC).
 And I have to use a wireless keyboard/mouse if I'm not connecting via ssh (
http://www.amazon.com/gp/product/B004KSQANO/).  It's not ideal, and a
little annoying that the accessories are more than the cost of the
Raspberry Pi.  But it works.

The USB port is slowed down by adding "dwc_otg.speed=1" to /boot/cmdline.txt

-Theron
^

On Tue, Oct 29, 2013 at 12:03 AM, s p <sebpiq at gmail.com> wrote:

> Same here ... I tried with 2 different usb interfaces, and I got no luck.
> In both cases I got "some" sound input, but there is a lot of popping
> sounds.
>
>
> 2013/10/28 Chris Jack <christopherdanieljack at gmail.com>
>
>> Hey folks,
>>
>> Apologies as this post is not strictly about Pd, though Pd will be a
>> crucial part of my final setup so whatever solution I find ought to work
>> with Pd. Also, there is a chance the issue might lie with Pd. I just don't
>> know.
>>
>> I'm looking for a usb bus-powered audio interface for the Rpi that can
>> take a stereo input and provide stereo output *at the same time.*
>> * *
>> I have tried a couple different images and a couple different audio
>> interfaces, to no avail. Perhaps there's something can be done with one of
>> these setups to get it working?
>>
>> First, the Pd-LA custom Raspian (v1) image and Pd 43.2:
>>
>> ..with Behringer UCA202 (at 44100khz):
>>
>> Alsamixer picks the device up but the input section shows nothing.
>>
>> Pd (gui) audio preferences allows selection of the interface for both
>> input and output. Output only is lovely and clean but as soon as the device
>> is selected for audio input the audio quality drops horrendously (vaguely
>> recognisable from the original signal)..
>> ..although what gives me hope is I CAN software monitor the input
>> (poorly) in 'Test Audio and MIDI' with this arrangement.
>>
>> ..with Behringer UCA202 (at 48000khz):
>>
>> Output only in Pd is poor (beating and popping sound - possibly sounds
>> like a samp rate conversion issue).
>> When device is selected as Pd input software monitoring is possible and
>> oddly, though the result is still poor, there is effectively no drop in
>> quality from having the device selected only for output and the monitored
>> signal sounds drastically better than at 44100khz.
>>
>>
>> ..with Turtle Beach Amigo II* (at 44100):
>>
>> Alsamixer shows both input and output and allows to change gain of both.
>> If plugged in from boot and only the output is selected in Pd it works
>> but with a lot of jitter. Selecting the device for input too causes a
>> further drop in audio quality although again I can software monitor the
>> input in 'Test Audio and MIDI'
>> If plugged in after boot the OS crashes.
>>
>>
>> The Satellite CCRMA (operating via ssh) and Pd-extended:
>>
>> ..with Behringer UCA202 (at 44100 and 48000):
>>
>> Alsamixer picks the device up but again the input section shows nothing.
>>
>> If I have the device plugged in from boot then I get the same behaviour
>> with it as I do in Pd vanilla on the Pd-LA Raspian image, ie. software
>> input monitoring but at an extremely poor quality.
>>
>> If I don't plug the device in from boot I see it in Pd audio prefs but
>> get this:
>>
>> ALSA input error (snd_pcm_open): No such file or directory
>>
>> ALSA output error (snd_pcm_open): No such file or directory
>>
>> from the Pd terminal and this
>>
>> ALSA lib pcm_hw.c:1401:(_snd_pcm_hw_open) Invalid value for card
>> ALSA lib pcm_hw.c:1401:(_snd_pcm_hw_open) Invalid value for card
>> oops: ALSA cards not reported in order?
>>
>> from the ssh terminal.
>>
>>
>> ..with Turtle Beach Amigo II* (at 44100khz):
>>
>> Alsamixer shows both input and output and allows to change gain of both.
>>
>> If plugged in from boot and then only output selected in Pd I get clean
>> audio out. If I try to select the Turtle Beach as audio inout in Pd then Pd
>> stalls indefinitely when I try to 'Test Audio and MIDI' or make anything in
>> a patch.
>>
>> Same direct input monitoring by default.
>>
>> Also get
>>
>> ALSA input error (snd_pcm_open): Device or resource busy
>>
>> ALSA output error (snd_pcm_open): Device or resource busy
>>
>> from the Pd terminal if I don't have it plugged in from boot, though no
>> message in ssh terminal.
>>
>> *It also appears that by default the Turtle Beach does direct input
>> monitoring of some sorts, the output stage sending out a clean copy of
>> whatever signal is going into the input stage whenever the device is
>> plugged into a usb port. With the Pd-LA image this occurred simultaneously
>> while input monitoring in Pd. I guess this is part of the design of the
>> Turtle Beach, though their documentation is devoid of any useful info
>> regards this. If this is the case then this ain't the sound card for me,
>> though clearly some might find this a very useful feature.
>>
>> Just to give a bit more info about what I'm attempting: I wish to run the
>> stereo input from the Turtle Beach through Pd, play with the audio signal
>> using data from an accelerometer (not nearly there yet) and then send the
>> audio out through the Turtle Beach's stereo output.
>>
>> Apologies for the essay. Hopefully my findings are useful for others and
>> hopefully I can get my rig working! Help muchly appreciated. I've probably
>> left out some crucial bit of info so please shout me if I have!
>>
>> Cheers,
>> Chris Jack.
>>
>> Chris Jack
>>
>> *art/research*
>> http://itsmrjack.com/
>>
>> *discus jockeying/sound art*
>> http://soundcloud.com/itsmrjack/
>>
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>
>
> --
> *Sébastien Piquemal
> *
> *
> ** *-----* @sebpiq*
>  -----* *http://github.com/sebpiq*
> *
>  ----- http://funktion.fm
>
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