TV-card audio NOISE

[antzen]

Hi,

I bought myself a "Hercules SmartTV Stereo" to try the capture "phenomenon". After testing aroud I found out that there were really bad sound quality. First of all, the frequency cuts off at around 16kHz (not nicam stereo as announced?). Secondly, there's some strange noise (static) in the audio. I've recorded this static and it can be found here
http://industrial.mine.nu/noise.mp3 (617kb). I can clearly hear some white (?) noise as well as some strange regular "beat" which has a bpm of around 162. I've no idea what this can be...

Any suggestions about what's causing this. Some ideas I have are the components in my box (see my profile for details).

Thanx!
/antz

PS! Yes, I'll return this card since the quality is just too bad and I'm aiming towards an external usb2 unit instead...

[Sosai X]

Sounds like you might be getting RF interference from something. Maybe one of your fans is dying?

[antzen]

yes, some kind of interference.. a fan u say.. hmm.. maybe, there's alot of fans in the box.. I tried using my vcr as a tuner instead of the on-board tv-tuner, and guess what, the video interference suddenly disappeared... this makes me to conclude that the environment for tv-cards within my box isn't at all preferrable... I will definetly return this tv-card.. and get myself something external instead...

thanx for the answer tho'

/antz

[Browney_wigan]

That defiantly sounds like interference from your hard drive to me

[antzen]

Yep, you could be right about the harddrives, I got 4 x 7200 rpms in there.. I tried to connect my VCR's tuner to the tv-card composite, and guess what, the audio noise is gone...

Although, I don't want to have to use the VCR so I'll probably get myself a USB2 "tv-card" instead, perhaps Pinnacle PCTV deluxe... ( I don't want to spend a fortune on this, $200 seems affordable)...

Thanx

/antz

[Browney_wigan]

I don't know why connecting it to the composite video in would effect the sound

i have an external usb sound blaster extigy so i don't get any audio noise i would recommend it to anyone who does a lot of capturing.

[tito13kfm]

I've noticed this on my capture card as well where the coax provides WAY too much noise, but if I use the component capture for the video, and then use my sound card for the audio the noise is gone. I took the capture card apart (just removed the shielding around the coax input and noticed it was about a 1mil thick piece of tin(foil?) ) so I guess that would be the explanation.

By the way, I was able to construct a crude interference blocker out of an old cd-rom drive and a dremmel and it cut out about 90% of the noise.

you could just purchase a rf modulator(or demodulator, or whatever this would be) that accepts coax as input and outputs as component. Input Video to the cap card and audio to ur sound card. You'll need a RCA->Stereo 1/8 plug converter, which you can buy at radio shack for like $6.

Grr.. Composite not component..

[antzen]

Browney_wigan:

You misunderstood, the audio-noise only occurs when I use the internal TV-tuner. The card itself has a audio-out that should be connected to line-in on the soundcard (Audigy btw), and I know that there's nothing wrong with the soundcard since I use it in other applications without any problems. It's the onboard TV-tuner that's being interfered by other hardware in the computer (as I believe anyways).

tito13kfm:

You wouldn't happen to have any pictures of your mod? It would be really interesting to see exactly what you've done.. (pm me about email if so...)

I will buy an external thingy instead since I really think this will help removing any interference (not counting atmospheric stuff etc etc)..

thx
/antz

[tito13kfm]

Nope, no pictures of the mod.. it's in a closet somewhere.. with my box of other things I did for no apparent reason except that I can. Basically I just built a large metal Shield around the whole capture card ( I was just proving my theory to myself that it was interfierence from my computer, and not the cable like the guy at radio shack insisted, and wanted me to buy MONSTER cables.)

I dissasembled the CD drive to get the thick metal shell off, cut some holes for the inputs to stick out of.. soldered some more metal on the back, attached it to the capture card with some duct tape, had to SHOVE it into the slot, but it sorta fit and bingo most of the noise was gone. I guess if I wanted to I could have modded it with an exhaust fan and such, filled in some of the gaps, or used thicker metal to really reduce the noise, but screw it I had a working solution that was a lot less hassle.

Now this is getting totally off topic so any more discussion of this will have to be by PM