[mythtv-users] Strange Audio Behavior - Static in One Speaker

[Tom Burt]

On Sunday 22 January 2006 17:13, Dave Bixler wrote:
> I've been searching the lists for the last few days trying to find out
> what I may have done wrong to cause the behavior that I'm experiencing
> with no luck so I finally decided to ask for help here.
>
> Everything is working very well and my system is stable.  I can watch TV
> using the TV Viewer in Redhat FC4 and if I un-mute the line in, audio is
> flawless.  Sound/music also plays flawlessly.
>
> So, I have the patch cable from the Hauppauge WinTV Go Plus to the line
> in of my Diamond Monster Sound audio card.  When I run MythTV and select
> Watch TV, it fires up fine.  However, only the right speaker has audio.
> The left speaker starts having a tiny amount of static.  This static
> then starts getting louder about every second preceded by a small "pop"
> sound.  Each time, it's as if the volume of the static is doubled until
> it becomes so loud it just distorts horribly.  If I use kmix and slide
> the balance all the way to the right speaker, I still hear the audio
> from the TV card fine.  If I slide it all the way to the left, it's pure
> static.  Does anyone have ANY suggestions whatsoever?  I'm including
> potential hardware info at the end of this message and if I've forgotten
> anything, or can include additional information, please let me know.
> I'm dying to have this working, it's such a sweet application!
>
> Thanks in advance for any insight!

I think I have a very similar problem to yours except that I have TV audio on 
the left hand side. I'm still testing my problem and trying to find a 
solution. My findings so far:
- if I unmute line in, audio is perfect with tvtime
- if I mute line in, I get sound from the left speaker in myth. However, sound 
from the right speaker is not simply static, it is recording form the mic! 
Yes, that's what is happening: left input is line-in, right input is from the 
mic at the same time! Please check if this is your case, too. I have two mic 
plugs, one in the front, one on the rear side of the machine, so if you 
happen to have a similar PC, you might need to also select the correct mic in 
kmix to check this.
- I can reproduce the "pop" sound getting louder, can't remember which setting 
influences this in kmix, but by playing around with controls I could easily 
get rid of this problem. I cannot check this right now, as a longer recording 
is in progress on my box.
- the problem does not seem to be related to myth however: if I eg. record 
sound from line in with krecord, the same thing happens: the left side is 
recording from the line input, the right side from the mic.

I suspect the problem is that the sound driver is incompatible with the mixer 
circuit in the integrated sound card. My motherboard is an ASUS A7N8X-X 
(nforce2 chipset). Recording works perfectly under Windows, at least.

I have no idea where to go next, already tried google, without success. But 
I'm not an expert in Linux...

Tom