VHS-C audio very low

[ido22]

I have a few tens of VHS-C tapes which I would like to capture, and I'm currently experimenting whats the best way.

I do not have the original camcorder which they were recorded on., so I am using a VHS adapter, and playing back on a Sony VCR.
I have noticed that some tapes (more then a few, hard to tell how many, but in no particular tape order), have VERY low audio output.

I have tried playing on a different VCR, with no luck.
I also tried playing with tracking and cleaning the audio head on the VCR.

I have attached a .wav capture from one of the tapes. The piano was right beside the person which recorded, and yet the volume can't be heard unless you take it up all the way.

Could the Adapter be the problem ?
Any ideas on how to fix this ? (I prefer not to do post processing on the audio captured, if possible)

[davexnet]

The sound,as you say, is very low and there's also a great amount of noise, similar to a hum.
If you normalise it so you can hear it, the noise is louder than the signal.
Possibly some bad cables?

How did you capture this file? You haven't described anything about how you got the sound into the PC, for example,.
what capture device or software you used.

[edDV]

VHS camcorders are noisy. They can use linear or HiFi audio tracks. Linear are worse than audio cassette and often lack Dolby B/C. FM HiFi tracks are highly influenced by tracking since they are part of the video track.

Beyond that there seems to be some post capture issues particularly the hum.

The VCR should be switchable to linear or HiFi tracks.

[ido22]

Thanks for the answers:

I haven't described how I captured, since its a cassette/VCR issue. Its low also when I watch the tape on the TV.

As for switching the audio tracks - I'll search for a VCR that can do that. What exactly am I supposed to look for ?

[davexnet]

Most HIFI vcr's defaults to the hifi tracks if they're present. Regardless of that, there's usually
a button on the remote, or a menu item in the VCR that let's you choose which track you want.

If, as you say, the tapes are like that and it's not a problem with the capture, you'll have to clean it up
afterwards in an audio editor if the material is important to you.

[pandy]

First check level on tape, if it is low only DSP can help - however it sounds like or very bad recording or more likely wrong setup - check grounding loop, cables, settings on mixer for input - select low impedance input, connect grounds of computer and VCR with cable, provide power supply to computer and VCR from one point (power bar) - recording is monophonic - record as stereo then ADD two channels together - this should reduce noise and increase level, use some decent DSP software, record few second of silence (no tape played) as noise profile.
Subtract spectrum of such profile from recording.

[davexnet]

Here's a quick a dirty attempt using Sound Forge 8 and Sony Noise reduction.

[ido22]

Thanks for the input everyone.

I just got my hands on a VHS-C recorder. I'll test it tomorrow!

pandy:

- How do I check the volume level on the tape ?
- I don't have a mixer, the VCR is connected to a TBC-1000 and then to the advc-100.
- As I said before, I haven't checked all my tapes yet, but on at least a handful of them, they sound like this one (no particular brand of tape, or time recorder - some older, some newer).
And As for computer-connectivity setup, I suppose its fine, as the rest of the tapes sound great (or am I wrong with this assumption?).


I'm not sure which software works in the way you mentioned (subtracting backround noise profile), however dave's output sounds fine for me (better then before), so worst case I'll just run it through that.

PS: after extracting the audio channel for processing, how can I combine it back to the original .DV video ? (for archiving)

[pandy]

pandy:

- How do I check the volume level on the tape ?
- I don't have a mixer, the VCR is connected to a TBC-1000 and then to the advc-100.
- As I said before, I haven't checked all my tapes yet, but on at least a handful of them, they sound like this one (no particular brand of tape, or time recorder - some older, some newer).
And As for computer-connectivity setup, I suppose its fine, as the rest of the tapes sound great (or am I wrong with this assumption?).

Normal play - just trying to figure potential misconfiguration setup - if during play-out you are able to hear normal audio but when digitized is so low it means some problem with configuration but if audio is poor on play-out and in computer it is simply poor recording and some restoration process is required.

By mixer i mean settings for capture card - for sure you can set "sensitivity" on analog audio - if normal pc audio card in line-in mode is used then you use mixer from windows to set REC source and level.

I'm not sure which software works in the way you mentioned (subtracting backround noise profile), however dave's output sounds fine for me (better then before), so worst case I'll just run it through that.

lot of softwares use this way to deal with noise - they operate in frequency domain not in time domain - for example Adobe Audition, Audacity etc Dave used SF in similar way (i assume)

PS: after extracting the audio channel for processing, how can I combine it back to the original .DV video ? (for archiving)

What software you are using now to perform video operation - usually most video editors offer option to replace or mix multiple audio tracks - thus you should be able to replace old track with new or mix in the way that previous one is not hear able and new one i fully hear able.