Clicks and Pops playing music.

[Nikolas Britton]

Jorge Mario G. wrote:

> --- Nikolas Britton <freebsd at nbritton.org> escribió: 
>  
>
>>After switching my main box from windows to freebsd
>>I have notice a shit 
>>load of clicks and pops when playing my mp3s. I have
>>have a relatively 
>>nice sound system setup on my computer (SoundBlaster
>>Live!, high end 
>>Yamaha 2.1 speaker system, and my mp3s encode at
>>150KB VBR) and this is 
>>really annoying me.
>>    
>>
>What exateley do you mean by clicks and pops? and when
>did they occur?
>A blind tip> try enabling virtual channels
>
>Jorge Mario
>
>  
>
Thanks jorge, I had maxautovchans=4 already set but you spurred me on to 
read the man page for snd and figure out what all the sysctl's do. In 
the man page I found this:

"hw.snd.targetirqrate:
Set the default block size such that continuous playback will achieve 
this IRQ rate.  This value can be tuned to improve application 
performance.    Increase this value when the sound lags and decrease it 
if sound stutters or breaks up."

On a whim I change this from 32 to 48 via /boot/loader.conf and 
rebooted. This (so far) seems to have done the trick, I have not heard 
any clicks, pops, or other abnormal artifacts when playing my music.

So, for anyone that uses the  SoundBlaster Live! and Audigy cards 
(snd_emu10k1) you might want to try this, here are my settings:

$ sysctl hw.snd
hw.snd.targetirqrate: 48
hw.snd.report_soft_formats: 1
hw.snd.verbose: 1
hw.snd.unit: 0
hw.snd.maxautovchans: 4
hw.snd.pcm0.buffersize: 4096

/boot/loader.conf:
## Sound Support
#sound_load="YES"
#snd_emu10k1_load="YES"
#snd_driver_load="YES"
hw.snd.maxautovchans=4
hw.snd.targetirqrate=48

Kernel config file:
# Sound Support
device          sound           # PCM audio device infrastructure
device          "snd_emu10k1"   # SoundBlaster Live! and Audigy PCI 
bridge device driver

$ uname -a
FreeBSD spectra.intranet 5.3-RELEASE-p2 FreeBSD 5.3-RELEASE-p2 #0: Thu 
Dec  2 19:09:20 CST 2004     
nbritton at spectra.intranet:/usr/obj/usr/src/sys/SPECTRA  i386


now... I just need to figure out how to disable Line-in and Mic for a 
better SNR, any takers?