[LAU] debugging hiss

[Rustom Mody]

On Fri, Mar 14, 2014 at 7:34 PM, Fons Adriaensen <fons at linuxaudio.org> wrote:
> On Fri, Mar 14, 2014 at 07:16:47PM +0530, Rustom Mody wrote:
>
>> No jack (to start with at least when the hiss sound starts)
>> I am using debian -- which meant that there was no pulse until recently
>> Of late I see occasionally some pulse related messages.
>> eg I get these messages when I start audacity:
>>
>> ----------------------------------
>> ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
>> ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
>> ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
>> ALSA lib pulse.c:243:(pulse_connect) PulseAudio: Unable to connect:
>> Connection refused
>>
>> ALSA lib pulse.c:243:(pulse_connect) PulseAudio: Unable to connect:
>> Connection refused
>>
>> Expression 'stream->playback.pcm' failed in
>> 'src/hostapi/alsa/pa_linux_alsa.c', line: 4611
>> Expression 'stream->playback.pcm' failed in
>> 'src/hostapi/alsa/pa_linux_alsa.c', line: 4611
>> Expression 'stream->playback.pcm' failed in
>> 'src/hostapi/alsa/pa_linux_alsa.c', line: 4611
>> Expression 'stream->playback.pcm' failed in
>> 'src/hostapi/alsa/pa_linux_alsa.c', line: 4611
>> ---------------------------------
>
> First of all disable Pulse, or get rid of it. Don't know how to
> do that on Debian.
>
>> Hardware: There is only one connection -- the speaker into the soundcard.
>> No mic, no line.
>> For now, I checked with xfce4-mixer.
>> If I turn down master or front-mic the hiss reduces
>
> So you are sending the mic signal (which will be lots of hiss when no
> mic is connected) to the speakers.

Yes
But how am 'I' sending that signal?
I dont have any .asoundrc

Is there some other place to look for configs?

>
>> However then musescore (my main use right now) also becomes too soft
>
> That should not depend on any 'Mic' settings, only on 'PCM' and
> 'Master'. If it does, that means the upgrade botched your ALSA setup.
> Try turning down (or switching off) anything 'Mic'.

When I turn off Mic my playback shuts off