sound problem a7v266e and avermedia tv card recordings

[michel]

hi there all
hope someone can explain this... I have an asus a7v266e and use the
onboard cmedia audio. I also have a tv card (avermedia tvcapture98).
watching tv channels the sound is fine and clear, recording (using
either the avermedia software or third party software such as
showshifter, windvr, aviio etc) also seems to be clear sound while in
record mode but the recorded files come out all hissie (it is the only
way i can describe it but the noise is more than just hiss, maybe like
a bad AM radio reception) - doesnt matter what compression i use, even
with uncompressed audio and video it still the same. It is even the
same if i try to use the windows sound recorder while tv is playing.
it seems to me that the problem is with the cmedia chipset as if it
was from the tv card i should have had the problem anytime i watch tv.
I also tried to connect a portable cd player to the line-in on the
soundcard and get similar results (but not as bad i think) when trying
to record. when connecting the cd player to the mic-in, the recorded
wave file is much better but when triong to connect the tvcard audio
output to the mic-in you cant hear any sound (with the mic booster
option in the mixer it comes out very very faint)
any ideas?
cheers
michel

 

[News Reader]

Hi,

I have had very similar problems with Hauppauge WinTV and A7S333 onboard
CMedia AC97 chipset. Very bad background hiss on TV audio recordings.

I likewise suspect this is a cmedia ac97 chipset issue as the WinTV used to
give faultless audio recordings in a previous computer using a PCI SB16
soundcard. Have also tried substituting the microphone for input but is not
a great deal better (although is perfectly audible).

As with your configuration, listening is crystal clear, only when recording
does the hum get added to the sound file.

I have also tried shifting the card into different PCI slots and adjusting
PCI latency timer in BIOS to no effect.

I hope someone in this newsgroup knows something about this and / or a fix
for it. It is a shame to let such a problem let down an otherwise excellent
piece of equipment.

However, I somewhat suspect that at the price (cheap) of these CMEDIA AC97
on-board sound chipsets / codec driver combinations, the quality of
recording may not be deemed a number one priority. Almost certainly, the
much smaller group of us with TV cards needing improved recording quality
(especially avoiding cross-channel interference / cross-talk between
different circuits / paths for data / electricity), is unlikely to represent
a sufficiently important demand for Asus or CMedia to work out a fix for
this / upgrade their hardware accordingly.... maybe in time.... but sadly I
don't envisage they will be providing backward compatible updates / support
for older / existing hardware.

Here is hoping / waiting!


All feedback welcome.

 

[michel]

Dear Ed
thanks for the link - it kind of explains it though the technical
terms seems to fly over my head...
just a quick question, would it work if i put the two capacitors you
recomended on the audio cable between my tv card and the soundcard?
BTW my Tv card is a pci avermedia and my video card is a ati 7500
radeon but i assume that the problem is in with the tv card although
your posting seems to suggest theproblem lies with the ati chip...
cheers
michel

 

[michel]

not sure if the last post gone through so i send this qyestion again
(appologies if its a repeat...)
Dear Ed - thanks for the warning but my question is still standing, do
i attach the capacitors to the audio lead connecting the two cards or
do i need to put them on one of the cards themselves?
cheers
michel

 

[Ed M.]

Michel -
You can do whatever is most convenient.
Ed.