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View Full Version : High Pitched Whine on TV Tuner

EateryOfPiza
21st October 2007, 04:33
Hello all, I've been playing around with a TV Tuner card I just got, and I've been noticing a high pitched whine on all of the recordings. You can hear it especially on periods of silence during a show, and it is quite annoying.

This file is a 5mb wav sample of what I'm talking about. Here is the source chain: Cable TV -> WinTV-HVR-1600 -> Beyond Tv 4.6, which outputs a .mpg -> DGIndex (Extract all audio streams) which outputs a .mpa -> Audacity (grab a small sample) outputs a .wav

Sample here: http://mihd.net/e52uyg

I don't know if this affects anything, but here are my computer specs: Intel Core 2 Quad Q6600, Gigabyte GA-N680SLI-DQ6, EVGA 8600GTS Superclocked, 2GB Patriot RAM 4-4-4-12, running Windows Server 2003 R2 Enterprise x64 SP2.

How can I get rid of this whine?

Thanks in advance
laserfan
21st October 2007, 16:06
Assuming the tuner card itself is not bad, it sounds possibly like an interference/internal noise issue. I would try first moving the card to different PCI slot(s), and you might also look in your BIOS for a "Spread Spectrum" setting and change it (looky here (http://www.lostcircuits.com/advice/bios2/13.shtml)).
EateryOfPiza
21st October 2007, 17:49
Oh I forgot to mention that when I recorded OTA HDTV, I heard no such whine. If it were a card issue, wouldn't the OTA HDTV also have been affected?
laserfan
21st October 2007, 22:13
I've been noticing a high pitched whine on all of the recordings.If it's not "all" then which is the whine on--analog (NTSC)? Then it surely must be interference--digital TV i.e. HD is not susceptible to the same effect. You might get pixelation & audio "breakups" but not "whine".
EateryOfPiza
21st October 2007, 22:24
Ohh i see what you mean. Since the digital HDTV is a a bitstream, electrical interference cant mess with it. Since the analog cable is electrical, these can be slightly changed with nearby the presence electrical fields.

Is this a correct interpretation?

Also, is there anything I can do now with my current recordings to restore the audio?
Coolpplse
22nd October 2007, 04:15
Ohh i see what you mean. Since the digital HDTV is a a bitstream, electrical interference cant mess with it. Since the analog cable is electrical, these can be slightly changed with nearby the presence electrical fields.

Is this a correct interpretation?

Also, is there anything I can do now with my current recordings to restore the audio?

You could extract the audio out of your recorded file, filter the frequencies that emits this noise, resave and mix back into your recording and volia :)
laserfan
22nd October 2007, 19:17
Since the digital HDTV is a a bitstream, electrical interference cant mess with it.Well, it can, but what you'd see w/Digital TV is pixelization, vs. "noise bars" on Analog TV. And for audio, digital audio would probably suffer dropouts, while analog gets buzzing or whining as you have heard.

Yes you can demux the audio track, clean it up, and re-mux it again but this is certainly non-trivial to do. I would focus at this point on getting the "whine" out of your new recordings first.

BTW have you put a TV on the cable going-in to your WinTV just to make sure the noise is not originating on the CABLE and not in the WinTV board?
EateryOfPiza
23rd October 2007, 01:10
I dont have a television set, but I'll try to scrounge one up from a freind
EateryOfPiza
29th October 2007, 04:29
I borrowed a friend's TV, and I was able to hear the interference. I guess there is no hope then?

Spread spectrum:

I looked through my bios for the spread specturm settings, and I found this:
CPU Spread Spectrum -- Center Spread
PCIE Spread Spectrum -- Auto
MCP PCIE Spread Spectrum -- Auto
SATA Spread Spectrum -- Disabled
LDT Spread Specturm -- Auto

I didn't see what I needed to change, so I left it as is.

I didnt move the card's slot becuase I figured it would be useless if the interference comes from the source.
Mug Funky
29th October 2007, 06:03
depending on what kind of noise it is, you might get away with a notch filter.

maybe look for some software with a spectrum analyser. if the noise is what i think it is, then all you need to fix it is to filter out the TV pilot tone (15625Hz for PAL, ~15734 for NTSC - line rate * frame rate) with a narrow notch filter.
EateryOfPiza
29th October 2007, 12:53
depending on what kind of noise it is, you might get away with a notch filter.

maybe look for some software with a spectrum analyser. if the noise is what i think it is, then all you need to fix it is to filter out the TV pilot tone (15625Hz for PAL, ~15734 for NTSC - line rate * frame rate) with a narrow notch filter.

Would this be pre- or post-processing? Sounds like post processing to me, if so, would Audacity do the trick? After a quick Google, I found a plugin listed here: http://audacity.sourceforge.net/download/nyquistplugins

do a find for Notch filter.

I'll try it out when I get home from school.
laserfan
29th October 2007, 22:12
I would try to fix the source, checking first all my connections, right to the antenna. If you live in an apartment building or something maybe you can talk to a neighbor to see if they have the "whine"? The superintendant?

Sure you can filter it out later but... this takes time and it is always a compromise i.e. you will lose some audio quality in the filtration.
EateryOfPiza
29th October 2007, 22:21
I would try to fix the source, checking first all my connections, right to the antenna. If you live in an apartment building or something maybe you can talk to a neighbor to see if they have the "whine"? The superintendant?

Sure you can filter it out later but... this takes time and it is always a compromise i.e. you will lose some audio quality in the filtration.
Other people have the whine, and I've opened up a case with the housing staff. I doubt they'll do anything though.
EateryOfPiza
22nd December 2007, 04:26
Sorry for the tardy reply but school has been owning me in the face.

Anyways, I tried a notch filter at 15736 Hz, and it did not work. I tried a low pass filter at a cutoff frequency of 10000 Hz to try to reduce the volume of the tone, and the tone was still there. This leads me to believe the tone is not at that frequency.

I found a few seconds of the audio with only the tone and pulled up Audacity's Frequency Analyzer. I've attached a Exported text file (spectrumNOISE.txt) and an image (noiseOnly.jpg) showing what the Analyzer showed me.

spectrumALL.txt lists Analyzer export output from the first 32 seconds of audio.

EDIT: Seems the mods are a bit slow at doing the attachments, so i uploaded the noiseOnly.jpg to here: http://tinypic.com/view.php?pic=730hruq&s=1

(They are currently pending moderator approval)
EateryOfPiza
20th January 2008, 22:45
bump, this issue is still with me =(