[mythtv-users] Weird audio bleed-over with analog recordings

Bob Sully rcs at malibyte.net
Mon Mar 26 21:09:01 UTC 2007

Rod Smith wrote:
> On Monday 26 March 2007 14:09, Bob Sully wrote:
>> Hi all -
>> I recently picked up a full-blown brand-new Creative Audigy sound setup
>> (main sound card, daughter card and external box).  This replaced an
>> Audigy 2ZS card (that wound up going into another box) because of an odd
>> echo I was getting when I was watching LiveTV on one of my two pcHDTV
>> 5500
>> tuners in analog or S-video.  Unfortunately, that didn't change, but I
>> deal with it by using the other tuner for live TV when necessary.  There
>> seemed to be no way to get rid of it using the mixer.
> Have you tried muting the "Duplicate Front" mixer channel? I ran into this
> and
> added a brief mention of it to the wiki:
> http://www.mythtv.org/wiki/index.php/Sound_Troubleshooting#Echo_on_audio_input


Unfortunately, there's no such channel in Alsamixer (and for some reason,
KMix doesn't show the input channels on Audigy cards).  Any other mixers
that you know of which might?  I'm running the Fluxbox WM on this machine
and can use any of them.  In Alsamixer, there is a PCM capture, which I
can lower but not mute - that one seems to be the culprit, but when I
bring up mythfrontend again, the PCM Capture level is back up to where it
was previously (yes, I do save the setting on exit)...I don't know why it
won't stay down.

>> Not only did the new card not fix the echo problem (which does not show
>> up
>> in recordings), but since I installed it,  I am now getting bleed-over
>> of
>> audio from the set-top box into analog recordings (along with the
>> soundtrack of the recorded show - BOTH get recorded).
>> The audio-out from the STB is routed into the audio-in jack on one of
>> the
>> two tuner cards; the bleed-over happens randomly with recordings on the
>> analog input of either tuner, but not with the QAM channels.  The echo I
>> mentioned above occurs while watching live TV on either the analog or
>> s-video input of this tuner only - the other one doesn't echo.
>> Anyone else seen this before and have a fix??
> I may have seen it before, but I don't have a fix. I've got a pcHDTV 3000
> card
> that's got some sort of audio bleed-over when recording via its tuner.
> It's
> possible the audio was intruding from the audio input jacks (connected to
> a
> DirecTiVo on my system), but I hadn't thought to check that specifically.
> As
> I no longer use the card for TV recordings I can't check that very easily.

That was my guess also, but I never had it happen with the Audigy 2ZS
card, so I think it's the sound card's fault...it's also intermittent,
which is the toughest type of bug to squash.  I'd rather keep using this
card, but if I can't get this fixed I'll have to swap it out.  :-(


Bob Sully - Simi Valley, California, USA

Bob Sully - Simi Valley, California, USA

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