Aha! I actually do remember this being an issue with my old hardware and it was something that was fixed by making sure to plug the audio in directly to the machine and not through a hub. Unfortunately, this doesn't solve the issue on the rPI, but disabling the Ethernet port *and* unplugging my wifi dongle does. The crackling is the USB bus probably not honoring the realtime audio requests of the UA-25 ... which pretty much sucks since I do need networking. This seems to be a recurring thread with *professional* audio cards and rPI.

Basically, it does work in full duplex ... but only if you don't plug anything more then a keyboard in addition to the soundcard.

My old hardware may have been slower, but apparently the USB setup was alot more robust. Hopefully this is something that can be fixed in later rPI firmware updates, but for now I can't run my entire system on a pi without networking :P

On May 5, 2013, at 11:19 AM, Dan Wilcox <danomatika@gmail.com> wrote:

I tried the latest firmware (alsa mmap update) and still the same issue. PD cpu usage seems lower now though, at about 8% with a simple test patch and stereo out.

Don't get me wrong, stereo audio out works with the UA-25 on rPI. The issue is that full duplex (stereo in & out) do not, resulting in crackling audio out. :P

On May 4, 2013, at 12:51 PM, pd-list-request@iem.at wrote:

From: Dan Wilcox <danomatika@gmail.com>
Subject: Re: [PD] UA-25 on RPI
Date: May 4, 2013 12:50:47 PM EDT
To: Antoine Villeret <antoine.villeret@gmail.com>
Cc: pd-list list <pd-list@iem.at>, Miller Puckette <msp@ucsd.edu>


No thanks. The UA-25 is bus powered, has two XLR+jack inputs, phantom power, rca/jack outputs, direct monitor, individual channel gain control, master gain control, and in a road tuff metal case. I have two of them, so it makes sense to dump the PI if I can't get it to work with proven linux friendly hardware especially when the pi costs less.

Too bad. Back to iPad now ... :D

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Dan Wilcox
@danomatika






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Dan Wilcox
@danomatika