Jay and list,
On Thu, May 4, 2017 at 9:23 AM, Jay Foster <j...@systech.com> wrote:
>
> On Thu, May 4, 2017 at 8:24 AM, Jay Foster <j...@systech.com> wrote:
>
>> I have encountered a strange problem. About 6 months ago, I added a USB
>> sound adapter and alsa to an ARM based linux system. I used aplay to
>> play wav files successfully.
>> Now, the playback has a crackling noise in it. I can not find anything
>> that has changed. A few units still play with no noise, but I cannot
>> determine any difference between them and the ones with the noise.
>>
>> One odd thing is if I run an application to make the CPU busy while
>> playing the audio wav file, the noise seems to go away. Any ideas on
>> where to look for the root cause?
>>
>> Jay
>>
>>
> I have had a similar experience using an AudioQuest DragonFly and a CuBox
> i4. In my case, errors were reported in syslog. Do you show any errors
> there?
>
> Do you have any other USB sound cards to try out?
>
> I have tried 3 different USB audio dongles (all C-Media chip based). No
> difference.
> No messages in /var/log/messages.
> I had to put the following in my /etc/asound.conf file to get clean
> playback when I originally got this working (the CPU is too under powered
> to do the default rate conversion).
>
> defaults.pcm.rate_converter "linear"
>
> The noise is also present using 'speakertest -c 2 -t wav'. What bugs me
> is that this used to work fine, and still does if I make the CPU busy,
> which seems counter intuitive.
>
>
Hmm. any reason you are doing rate conversions? Have you tried to play
your files with the hw:CARD=???,DEV=??? argument?
--
Chris Hermansen · clhermansen "at" gmail "dot" com
C'est ma façon de parler.
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