[mythtv-users] tinny high pitch audio in recordings

Tom Walsh tom at openhardware.net
Tue Nov 1 09:23:49 EST 2005

Joel Oliveira wrote:

> Hi everyone -
> I just got my first myth box setup (finally) using a year old dell 
> dimension box and a pvr-150 ... thanks to Jared everything was pretty 
> much a snap.  A few things crept up here and there but nothing I 
> couldn't figure out.  
> One thing I've noticed since recording my shows, though, is that the 
> mpeg2 files, when played back on both the mythbox and my windows 
> machine, have audio that sounds a bit off.  There's a high pitched 
> whine in the background of the audio as well as a tinny effect on 
> voices.  I figure this might have something to do with the audio 
> processing of the PVR-150? Maybe the recording volume on that device 
> is too high?
Sounds to me like you've got some stray signal coupling somewhere.  
Possibly a sound card mounted close to the PVR-150 and the PVR-150 is 
"hearing" the electronics of the other card?  You may have something 
where some oscillator on the motherboard is running at the IF 
(Intermedite Frequency) of the tuner module on the PVR-150.

This type of problem has not been much of one in recent years, but ask 
any Ham Radio operator how badly some motherboards will interfere with 
his radios.


Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."

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