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-   -   Remove audio hiss during VHS capture? (https://www.digitalfaq.com/forum/video-capture/10642-remove-audio-hiss.html)

loveclairebearx 05-19-2020 03:24 PM

Remove audio hiss during VHS capture?
 
I'm capturing VHS-C tapes in a JVC deck using S-video with red & white composite cables for audio.

There's an audio hiss in both playback and capture. Any thoughts on ways to remove this? I already tried switching from stereo to mono settings and while the hiss is less noticeable, it's still there.

latreche34 05-19-2020 04:04 PM

In HiFi stereo there is no hiss, probably the VCR is just stays on mono linear track all the time since most low budget camcorder didn't record HiFi stereo anyway. One place to start is try to clean the fixed audio head with q-tips and alcohol.

lordsmurf 05-20-2020 12:06 AM

Quote:

Originally Posted by latreche34 (Post 68815)
q-tips and alcohol.

Never cotton swabs! :mad4:

Q-tip branded or generic/others.

Chamois, non-cell foam, or dSLR sensor swabs only! :old:

loveclairebearx 05-21-2020 02:48 PM

I'm hesitant to open it up since the deck was sent to me in good working condition and I'd hate to damage anything.

I fiddled around with adjusting the Sound Settings on capture, ultimately reducing the gain helped lessen the hiss, but doesn't fully eliminate it.

Doing a bit further research it seems like analog audio has fluid audio waves that don't perfect line up with our digital audio playback. Essentially this randomization in analog audio plays back as a low white noise (also called the noise floor). So I'm not convinced this is a hardware issue anyhow.

Ultimately this is something I can further limit when I make my proxy H264 files in an editing platform with an iZoptope denoiser plugin, but was hoping to further reduce or eliminate it while capturing the masters.

lordsmurf 05-21-2020 03:13 PM

Quote:

Originally Posted by latreche34 (Post 68815)
In HiFi stereo there is no hiss, probably the VCR is just stays on mono linear track all the time

This is possible. But sometimes you need to verify VCR settings, verify it is set to HiFi. Sometimes you'll find that only 1 channel is bad, so you'll capture only L or R HiFi channel.

Quote:

Originally Posted by loveclairebearx (Post 68883)
I'm hesitant to open it up since the deck was sent to me in good working condition and I'd hate to damage anything.

This was one of my decks that you have. It works perfectly, no need to open it whatsoever. Non eed ot clean or whatever.

Quote:

Doing a bit further research it seems like analog audio has fluid audio waves that don't perfect line up with our digital audio playback. Essentially this randomization in analog audio plays back as a low white noise (also called the noise floor).
Where did you read that? It sounds like tecnobabble nonsense.

Quote:

So I'm not convinced this is a hardware issue anyhow.
It's not.

Quote:

but was hoping to further reduce or eliminate it while capturing the masters.
Capture audio at 50% levels in the capture software (or OS controls). I'm still not fully familiar with this newly-discovered ATI 600/clone Mac setup you're using, so careful observation is needed to fully tweak correctly. If capture audio levels are too high, hiss will overpower actual audio (and actual audio will be distorted).

Quote:

Originally Posted by loveclairebearx (Post 68813)
There's an audio hiss in both playback and capture. Any thoughts on ways to remove this? I already tried switching from stereo to mono settings and while the hiss is less noticeable, it's still there.

All VHS has hiss to some degree, both linear and HiFi. Some decks do better that others, but it also depends on the tapes. I have mono tapes that hiss loudly in JVC, but not Panasonic. Some in Panasonic, not JVC. Some hiss regardless of deck.

latreche34 05-21-2020 03:59 PM

You may have come across a tape with some mold on the edge and that will clog the audio head, I've seen it and dealt with it, Yes you may have bought the VCR in pristine condition but it doesn't mean you will never have to maintain it again, If you don't feel comfortable doing the very basic transport cleaning pay someone to do it for you otherwise you will have to live with low quality captures.

Eric-Jan 05-21-2020 04:02 PM

What is used as capture device ?

loveclairebearx 05-21-2020 08:25 PM

Quote:

Originally Posted by lordsmurf (Post 68885)
This is possible. But sometimes you need to verify VCR settings, verify it is set to HiFi. Sometimes you'll find that only 1 channel is bad, so you'll capture only L or R HiFi channel.

Looking at the VCR settings, it is showing Hi-Fi R. Which I assume is right only I'm not seeing anywhere in the VCR Manual (JVC_SRMV40) or on the remote how to switch it to stereo. Any advice on how to go about checking this?

Quote:

This was one of my decks that you have. It works perfectly, no need to open it whatsoever. Non eed ot clean or whatever.
Fantastic - this is what I thought

Quote:

Where did you read that? It sounds like tecnobabble nonsense.
From the blog by iZotope: https://www.izotope.com/en/learn/dig...bit-depth.html It's towards the bottom, if you keyword search white noise, you'll find the paragraph. Perhaps I misunderstood.

Quote:

Capture audio at 50% levels in the capture software (or OS controls). I'm still not fully familiar with this newly-discovered ATI 600/clone Mac setup you're using, so careful observation is needed to fully tweak correctly. If capture audio levels are too high, hiss will overpower actual audio (and actual audio will be distorted).
I think the capture levels that VideoGlide defaulted to were definitely too high initially. As I mentioned, dropping them did stop the hiss from being overpowering, so this at least has made it much better.

Thanks for the insight.

loveclairebearx 05-21-2020 08:25 PM

Quote:

Originally Posted by Eric-Jan (Post 68887)
What is used as capture device ?

ATTI 600 USB clone

Eric-Jan 05-22-2020 06:54 AM

So, i guess there's no way to adjust any level during capture ?
then only to "remaster" the audio in post... remux ?

dpalomaki 05-22-2020 07:01 AM

Hiss is noise, and present in all recordings whether analog tape or digital, the question is at what level and what is the source. In good digital recordings the source of the hiss is mainly the self noise of microphones and amplifiers used ahead of the A/D conversion and should be generally inaudible if the person making the recording used good gear and technique. Recording made with gear that used automatic level control on the audio inputs may pump background noise and electronic generated hiss during the quieter portions of the recording. Cheap condenser microphones (including those often found in consumer camcorders) are especially prone to hiss. With analog recordings you can add the hiss generated by the tape and tape recording/playback process. (Direct-to-platter analog recordings, found mainly before the 1970s had similar issues.)

Relatively high levels of hiss is a characteristic of linear audio tape recording. Some tape formulations are more prone to hiss than others. Narrow audio tracks are more hiss-prone than wide audio tracks. Dolby audio recording was invented to help manage hiss. Recordings on the video tape Hi-Fi track will have a much lower level of recording/playback-generated hiss than linear track recordings because it is recorded using FM technology, similar to the benefits of FM vs AM broadcasts. As a notional comparison; hiss introduced by the recording/playback process in a VHS analog linear track without Dolby might be -40 dB, in the Hi-Fi track around -65 dB, and with digital around -90 dB. As noted above many VHS tapes will only have the linear track (sometimes called the "normal audio").

On to your problem, one approach to reducing hiss in the captured file is to use noise reduction filters in a program such as Audition. Applied with care the filters can clean up the sound appreciably without causing undue harm to the desired program material. However it is easy to over do it and end up with a weird Sci-Fi sounding audio recording.

A poor mans solution is to use tone controls or a graphic equalizer to reduce the treble. (This is very much like the "scratch filter" in old time audio amplifiers used with records.) However, while this approach can work OK with voice, it hurts musical program material. You could pass the audio signal through graphic equalizer when recording to do this as well.

Or yo could invest is something like this Rek-O-Kut unit, but that is not a poor man's solution
https://www.esotericsound.com/NoiseReduction.htm

Using a different playback machine "might" give some slight improvement, or might sound worse, depending on its equalization settings and the condition of its audio components including linear audio heads and head alignment.

Eric-Jan 05-22-2020 07:32 AM

Phase shift each channel somehow so the noise will cancel itself out ? the problem is that the hiss is in the recording itself...
you should have an audio processing device between player and capture device, during the capture, you loose sound quality in the high frequency range anyhow. (you might boost some of the lower frequencies, but that's a matter of taste.)

hodgey 05-23-2020 08:33 AM

I would suggest posting a clip of it, that makes it easier to hear if it's inherent tape noise or something wrong with the VCR.


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