pulse audio

Len Ovens len at ovenwerks.net
Mon Dec 19 07:49:52 UTC 2011

Any way we can get rid of pulse audio? Installed todays version of US (no
new problems) to try out some audio stuff. Installed audacity on top for a
quick and easy audio recorder... straight into alsa via pulse. This is my
netbook, so just the on board sound stuff which I had noticed before is
quite noisy. I'm not sure if there is a setting somewhere I can change
this... but two things. I never did get anything out of the built in mic.
(not a big loss as I recall, but pulse does have a switch to switch
between mic and input) It is the standard intel sound, but I guess there
are variations.

The big problem seems to be that pulse tries to be too intelligent. There
is a capture level and a mic boost level according to alsamixer. If I
leave pulse set to line, mic boost is 0 and pulse controls capture...
Good. But as soon as I switch to mic... still with an external mic. Now
the pulse level controls both the capture level and the boost level... it
seems to do them at the same time... the boost level seems to only have 8
setting (16 maybe?) but capture is a lot more (128?) So capture reaches 8
out of 128 when boost is full... BAD really BAD. So I manually set boost
low and capture full so that the meter in pulse shows what looks like a
reasonable level. Ok, now start audacity recording... this opens a port in
pulse, pulse looks at the level it has and translates it to how it does
things and mic boost is now full and capture is half and the recording is
noisy... Yuck! OK, delete track, put audacity in pause and record... pulse
goes nuts... while in pause set my levels... capture full and boost at 1
notch. Hit pause to roll. Sound is much, much cleaner... quite good
considering the mic is one of those things attached to my headset.

What pulse audio should do... is use the capture level from 0 to 128 and
then use the few boost setting on top of that. Too notchy for a good fade,
but that can be done inside audacity or ardour... complete with
automation. Would this be a bug or a design decision in pulse? It seems to
know what the controls it is playing with are as it only uses the boost in
the mic setting. The only advantage I can see is that one gets better
granularity the way they have it. I'll take sound quality thank you.

Problem two (or is that three?) once pulse has been in mic mode and boost
is now high, I change it back to line... boost stays high. I have to use
alsamixer to turn it off. This I think is a bug not a design problem.

Anyway, I personally think pulse is too buggy for input use. Outputs, it's
main reason for being, it does ok.... not commenting on cpu use just that
it seems to handle lots of outputs ok without user input or having to stop
one thing to listen to another.

Assuming an external mixer of some sort, the best setting is capture full
and mic boost off and use the external mixer to set levels. What this
means is that I can not use my netbook for impromptu recording as it sits.
The internal mic doesn't get turned on. This is not pulse but alsa (I
think). Maybe the driver I am using? I have had it working before with
ubuntu netbook or desktop so it can happen. More playing needed. An
external battery powered mixer and a mic or two would be the best deal...
a headset with a mic like I used tonight would get that new tune before I
forget what I was playing by going to sleep and be more likely to be with
the computer. Choices...

Some kind of text editor to write down lyrics would be nice too ;-)  I
know, it's coming.

Len Ovens

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