recording mic on audacity - strange gaps/pauses

toad · 2009-04-16 13:03:38

Subject says it all. Everything works great using alsa but when I record using the microphone I get strange gaps!?

Not sure which, if any, config files to post. Here my card:

toad@deskarch 301\6 ~ > lspci|grep Audio
00:1b.0 Audio device: Intel Corporation 82801JI (ICH10 Family) HD Audio Controller

R00KIE · 2009-04-16 19:14:38

I don't have a zoomed version of a capture now but does it look like this here http://bbs.archlinux.org/viewtopic.php?id=59505
I can give a description of what happened, imagine you had a perfect sinewave recorded but with some zero samples (just a few) somewhere at periodic intervals.
It was the most annoying problem I had with alsa, at the time I have tried the most up to date version of alsa, I have tried passing all possible options to the hda codec and even tried recompiling the kernel with a different timer value (since the problem was periodic it might be related), tried passing different buffer sizes and timings to alsa through asound.conf but no luck there. Only audacity was able to do flawless recordings and not always.
Then at the time I decided to give OSS a try, same stock kernel, same audio card (its a notebook ^^; ) and same headset, sound was and still is perfect every time. Never figured out what the problem was, I thought it must have been some nasty alsa bug that still seems to be there.

toad · 2009-04-16 20:07:59

Cheers Rookie - that quite simply sounds wild! With me I can talk into the microphone and it just refuses to record for about a tenth of a second or so.

I tried OSS on this 64 bit install but failed first time round somehow (can't remember what I had problems with). So I just went with the old workhorse alsa. I will try OSS and report back (if I can work it )

Last edited by toad (2009-04-16 20:08:27)

R00KIE · 2009-04-16 20:21:16

Mind you that getting OSS to record from my headset required quite a bit of trial and error, specially because the codec (Realtek 660VD I think) is unknown to OSS so I have all controls there with no names that can hint to what they do.
Check here for an example of what I have in ossxmix http://bbs.archlinux.org/viewtopic.php?id=67571

toad · 2009-04-16 20:46:52

Cheers again. OSS plays sound no problem. kmix, however, does not start anymore which was my means of adjusting the volume = bummer!
And I can't record yet. My ossxmix looks a tad different to yours with different colours which serve to confuse me more than anything else, but that is just me and it is new. However, I will persevere for a while 'cos I've got to throw a one hour radio show on linux together in ten days - and it would be nice to have the services of my desktop available to do so

R00KIE · 2009-04-16 21:01:13

Like I said my ossxmix is just an example
As for kmix ... no idea, I use xfce and I use ossxmix for my volume adjustment needs (started with ossxmix -b) although I have to admit that ossxmix is huge and could look better but it works as intended and that alone makes me a happy user

Bysshe · 2009-04-21 04:53:34

I had to switch back to oss, myself. I tried it some odd months ago, also, and switched back to alsa. But alsa just doesn't work really well, and it keeps crashing applications. I experienced the same audio gaps using audigy cards, which is just pathetic, and if a graphic intensive app is running and using sound, the application eventually crashes, which is one thing I know I can pin on alsa.

I suspect it causes general system instability to so much as even be loaded. I experienced this exactly in both Xubuntu, and Arch Linux on pure clean installs without ever entering oss into the equation. Hello Alsa Devs, problem!

I have seen alot of phantom problems "magically" disappear by ditching alsa. I hate to say that, because I'd rather use the default sound system, but then, who cares, oss works. It seems ossxmix comes with oss automatically. In testing, I found my capture slider to be labeled "AC97" in the "record" section. And the window had two sections, if you click the min/max button in the upper right it actually changes the view. You can use audacity for testing to tweak your levels down to minimize mic noise. I really like how it latches onto applications. How it works well with Wine if you uncheck "emulate driver", while sound quality is probably equal to what alsa was when alsa used to work at all some odd months ago.

And if oss survives kernel 2.6.30 and 2.6.31 I'll be convinced, because somewhere in there will be some heavy IRQ handling patches if I read correctly. Not that I know much about that, but I suspect it could amount to something. Changing how the kernel works with the CPU at the interrupt request level?...hmm...

good luck!

toad · 2009-04-21 05:32:18

Cheers (Percy) Bysshe (Shelley ),

I am afraid I've changed back to alsa 'cos I just couldn't get oss to record at all. I am also spoiled by kmix which apparently only plays with alsa. However, as of the latest kernel I am able to use my dirt cheap multimedia keyboard (with alsa definitely) so kmix' ability to control volume may not be so critical any more (if oss plays).

I'll certainly keep on trying oss, but no further functionality plus less accessibility has made me switch back for the time being.

Bysshe · 2009-04-21 22:24:39

Fan of Percy, yes.

But, I found oss to be a pain as much as alsa trying to find what, where, and how with the mixer settings. Familiarity is why I gave up on it the first time, and the window behavior is very odd with how you switch between the two views. I didn't spot it the first time. I also think that the mixer levels are alot more sensitive, so that it may even be possible to have the recording level too high causing too much distortion to record. Therefore, if it's not that it just doesn't work, it needs quite a bit of time to find the perfect settings.

But, gotta use what works best for you. I may be gack to alsa in a few months. Again, good luck

Bilon WW-a · 2009-10-13 18:29:51

hm..nie wyszukuje..OSS-LINUX..niemam windowsa..bo niemoge wyszukac z idle na acpi czy acpi na idle zeby wykrylo windowsa ale to tam juz..;p narazie musze z tym glosem zrobic..!@:D

Arch Linux

#1 2009-04-16 13:03:38

recording mic on audacity - strange gaps/pauses

#2 2009-04-16 19:14:38

Re: recording mic on audacity - strange gaps/pauses

#3 2009-04-16 20:07:59

Re: recording mic on audacity - strange gaps/pauses

#4 2009-04-16 20:21:16

Re: recording mic on audacity - strange gaps/pauses

#5 2009-04-16 20:46:52

Re: recording mic on audacity - strange gaps/pauses

#6 2009-04-16 21:01:13

Re: recording mic on audacity - strange gaps/pauses

#7 2009-04-21 04:53:34

Re: recording mic on audacity - strange gaps/pauses

#8 2009-04-21 05:32:18

Re: recording mic on audacity - strange gaps/pauses

#9 2009-04-21 22:24:39

Re: recording mic on audacity - strange gaps/pauses

#10 2009-10-13 18:29:51

Re: recording mic on audacity - strange gaps/pauses

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