At Mon, 12 Jan 2009 17:16:15 +0100, Krzysztof Helt wrote: > > On Sun, 11 Jan 2009 08:28:13 -0500 > "Theodore J. Allen" <tjallen@xxxxxxx> wrote: > > > The Soundscape Elite does work, but after a reboot > > I noticed that there is an oddness in that there's > > a little "pop" before playing sounds with aplay and > > a series of short spike pops before the sound plays > > with xmms, which uses the old oss interface. > > > > I traced this and the "pop" sound is caused by two > things: > 1. Codec autocalibration every time a new sound is > started (even when sound is muted it produces > the "pop" on AD1848). > 2. Muting sound on and off every autocalibration. > > The OSS code from the 2.4 kernel states that > autocalibration produced that "pop" so it got > disabled. This solves two problems at once > as the muting on and off is not required then > (and is not done in the code). > > I am not audiofile so I cannot comment how > audible the lack of autocalibration is. Most > codecs require it after they are powered up > (and most of them except the oldest ones > actually force it after powering up). One can > autocalibrate the codec only once > during a card/codec initialization. Yes, this sounds like a reasonable solution. > I can prepare a patch which disables the > autocalibration. This is the only solution > as I tested others like slow volume muting > but all others still produce some noise. In case it really matters, this can be controlled either via a kernel config or a module option. But, I have no ISA device (more exactly, a machine with ISA slot) now for testing, so it's really up to you guys... Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
