Annoying whitenoise sound coming from snd_hda enabled chipset

[Christoph Mallon]

Garrett Cooper schrieb:
>     I don't know how else to describe it, but when I turn up my
> speakers enough (50%+) and don't have any sound playing, I hear a
> whitenoise hiss coming out of them. When I change webpages (nvidia
> driver is GIANT locked) or do something else kernel intensive it stops
> for a brief second, but apart from that it's an annoying trill sound
> almost like a mosquito humming around me waiting to be swatted.
>     It's really driving me insane... Hopefully helpful snippets follow:
> 
>     vendor     = 'Intel Corporation'
>     device     = '82801IB/IR/IH (ICH9 Family) HD Audio Controller'
>     class      = multimedia
>     subclass   = HDA
> pcib2 at pci0:0:28:0:      class=0x060400 card=0x82771043 chip=0x29408086 rev=0x02
> hdr=0x01
> 
> [gcooper at orangebox /usr/home/gcooper]$ uname -a
> FreeBSD orangebox.gateway.2wire.net 8.0-CURRENT FreeBSD 8.0-CURRENT
> #1: Mon Feb 16 20:50:56 PST 2009
> root at orangebox.gateway.2wire.net:/usr/obj/usr/src/sys/ORANGEBOX  i386
> 
> Comments?
> -Garrett

Try setting kern.hz="100" in loader.conf.