Date: Sun, 30 Sep 2012 23:54:30 -0700 From: Doug Barton <dougb@FreeBSD.org> To: matt <sendtomatt@gmail.com> Cc: freebsd-current@FreeBSD.org Subject: Re: squealing/whistling audio Message-ID: <50693E26.4020207@FreeBSD.org> In-Reply-To: <5059636B.4020902@gmail.com> References: <5059194F.4090002@FreeBSD.org> <50595E93.9080908@gmail.com> <50595F83.9030008@FreeBSD.org> <5059636B.4020902@gmail.com>
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On 09/18/2012 23:17, matt wrote: > On 09/18/12 23:00, Doug Barton wrote: >> On 9/18/2012 10:56 PM, matt wrote: >>> On 09/18/12 18:01, Doug Barton wrote: >>>> Sometime in the last couple of months an old problem has resurfaced on >>>> HEAD, a sort of squealing/whistling sound in the audio, even without >>>> anything playing. The sound is similar to the wind whistling through >>>> something. >>>> >>>> Before I blindly go off on a bisecting spree, does anyone have a >>>> suggestion as to where I might look? >>>> >>>> Doug >>>> >>>> >>> Electrically that's usually oscillation (too high gain or too much >>> electrical feedback) or an unshielded input. >> Sorry, I should have been more clear. This problem doesn't occur in >> windows, or linux, and last time I checked, didn't occur in freebsd 8. I >> have everything irrlevant zeroed out in mixer. >> >> Doug >> > It was worth a shot. It is possible that each OS (and version) is > setting the associations up properly though except HEAD on your machine. > Is it a laptop or a desktop board? Desktop. > Any difference in the nid configuration between freebsd 8 and HEAD? No. > Does changing any of the hw.snd sysctls (latency, exact rate, vpc_0db) > have any effect on the sound? It doesn't affect the squeal. > http://freshbsd.org/commit/freebsd/r230551 might be worth a look. Didn't help. > I > couldn't find anything newer that looked like it would have an effect. > Their are some earlier commits around January that are dealing with > signal gain that could also have an effect. > > Otherwise, I'm not sure where else to look. Thanks anyway. Doug -- I am only one, but I am one. I cannot do everything, but I can do something. And I will not let what I cannot do interfere with what I can do. -- Edward Everett Hale, (1822 - 1909)
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