Subject:Improve VHS Linear Track Sound Quality

Posted by: johnmeyer

Date:5/3/2006 1:21:53 PM

I have a bunch of old VHS tapes to restore. They are recorded in the 6-hour mode (EP) and were recorded before "Hi-Fi" audio, so they only use the linear soundtrack. I believe the frequency response for VHS linear using the slow mode was well under 6 kHz.

Obviously I cannot create what isn't there, but are there any industry-standard acoustic trick that can be used to create a little more life to this muddled sound?

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: jackn2mpu

Date:5/5/2006 12:43:38 PM

Best thing you can do is to clean the heads of the VCR. That should give you a LOT clearer sound (and picture to boot). Other than that, try some shelving EQ.
Jack

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: maylee

Date:5/5/2006 7:19:57 PM

Perhaps something like the old Aural Exciter, a hardware box that synthesises harmonics of what's already there, giving the illusion of a brighter sound, or software plugin called Sonic Maximizer, can be found on the Sonar or Cakewalk web site. I believe it's still available.

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: johnmeyer

Date:5/5/2006 7:37:00 PM

try some shelving EQ.

That's what I've done so far. It helps.

I've looked at the Sonic Maximizer. I'm trying to find some before/after examples to download to hear if it is going to do the trick. Thanks for that tip.

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: rraud

Date:5/5/2006 8:46:40 PM

I forget who makes BBE Sonic Maximizer plugin. (PSP?) but, Beware: In my opinion, the software plug of the BBE Sonic Maximizer does not sound anywhere near as good as the great sounding hardware 862/462.

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: johnmeyer

Date:5/7/2006 9:36:50 AM

Had pretty good luck with the following:

1. Used Spectrum Analyzer to confirm that nothing above 8 kHz was anything but noise.

2. Used Paragraphic EQ to kill everything above 8.5 kHz.

3. Next used Noise reduction to kill hiss. One pass was sufficient, and I stayed well below 20 dB of NR.

4. Put a small +3dB bump back in at about 4.5 kHz. Didn't take much, and I had to listen to many different sections of the video to make sure I had it right.

Did an A/B with the original videotape when I was finished, listening on the big theater system. Results were much better than I had hoped for. Definitely not CD quality, but no longer sounds like EP linear audio.

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: plasmavideo

Date:5/11/2006 9:21:04 AM

John,
You might also look for a free DirectX Plug-in called RGC High Frequency Stimulator. I think I found it on Tucows, but it's been a while.

It recreates some high frequency information by generating some controlled harmonics from the high freq info that is there. You can adjust parameters like drive and cutof frequency so that the harmonic content is controlled and less harsh than you might expect from harmonic generation.

Also, if you have the full Nero, it's little audio editor has a band extrapolator filter that not only does the same sort of thing to hf content, it generates subharmonics of the bass frequencies as well.

There is one other from a German company that I tried their demo of and it worked well. I think it was Virtos. If I find the link to that one I'll send it to you. If you can't find the RGC filter, let me know and I'll email it to you. It is a freeware. I've had good luck with it.

Tom

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: johnmeyer

Date:5/12/2006 12:25:13 PM

Couldn't find the RGC plug-in (rumor was Cakewalk bought the code), but I do have Nero and, based on your advice, played with their "band extrapolation" filter. Doesn't sound too much different from just adding a little bump, although it is perhaps a little more natural. I'd have to do some A/B with my approach just to make sure. I have another similar project coming up next week and I'll try it on that. Your advice was REALLY good and MUCH appreciated. Unless you think the RGC or Virtos filters would be significantly different, I'll go with what I've got for now. (Actually, I just looked at the Virtos site, and based on the UI, it looks to be identical to the Nero plugin).

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: plasmavideo

Date:5/12/2006 1:31:38 PM

John,

I think you are right about the Virtos/Nero connection. I looked at the demo again and compared it. They are both German companies, so making an educated guess . . . . . . . .

Looks like the RGC plugin is no longer available. I found several sites saying as much and confirming the Cakewalk purchase. It offered a little more control of parameters and a slightly different sound than the Nero plugin.

Sometimes I've found that doing a 3 step process works better than a single pass with that type of enhancement. I've done a run with the cutoff at around 5 or 6K, then done a mild noise reduction to get rid of the hiss and then applied a second enhancement with the cutoff around 8K.

As you say, there might not be a big difference between that and just bumping up the high end, but playing around with a combination of both might net you a more open, airy sound.

The advantage to using the RGC filter is that I can chain it with the vinyl restoration, eq and a second pass of RGC in one filter chain in SF and check the total effect out, whereas I would have to dump out of SF and go to Nero to apply the HF stimulator. I haven't checked yet, but is the Nero filter a DirectX plugin? If so, maybe there is a way to get it into SF. I just purchased the full Nero several weeks ago, and I hadn't thought about checking out that possibility yet.

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: rraud

Date:5/12/2006 3:56:01 PM

Some of the nero plugs are VST. Not sure about the specifics.

The RGB HF-exciter works really well, (when used in moderation) and in my opinion sounds better than the software version of the BBE Sonic Maximizer.
The only problem I have with the RGB HF-E is it will not work in the chainer with SF-6, 7 or 8.
I have the RGB HF installer.exe around someplace... if someone wants it, I could find it.

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: MarkWWW

Date:5/13/2006 3:03:58 AM

Although the RGC:HighFrequencyStimulator is no longer mentioned on the old RGC website, it is still available to be downloaded from there.

As has been mentioned, these kinds of processors work by adding some harmonic distortion to simulate the information in the higher frequency areas that is missing for whatever reason. They have to applied judiciously to avoid overdoing things and just sounding distorted, but properly applied they can restore some of the edge and zip to an otherwise dull recording.

Mark

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: plasmavideo

Date:5/13/2006 10:25:19 AM

Interesting - I just confirmed that I could use the RGC plugin within a chain in SF 7. I used RGC, Vinyl Restorer and Wave Hammer in the chain.

T

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: rraud

Date:5/13/2006 6:18:56 PM

Thanks Plasma,
Maybe it's an issue with my system. RGB -HFX works fine in Vegas but crashes in a SF chain and requires a app. re-start.
This has been since SF 6-8d.
I'm confussed... and my PC is a DAW only.

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: johnmeyer

Date:5/14/2006 9:33:17 AM

Sometimes I've found that doing a 3 step process works better than a single pass with that type of enhancement. I've done a run with the cutoff at around 5 or 6K, then done a mild noise reduction to get rid of the hiss and then applied a second enhancement with the cutoff around 8K.

That is almost exactly what I have been doing. I use the Spectrum Analyzer to help decide what cutoff frequency to use and then apply a fairly severe cutoff above that frequency. I then take my Noise sample and do a noise reduction. Finally, I apply a bump, or use the Nero plugin you recommended.

I haven't checked yet, but is the Nero filter a DirectX plugin?

Yes, it is, and it shows up in the Vegas and SoundForge plugin list. However, when I click on it to load, it will not load. So, for now, it looks like it is a two-step process to use this filter. Not a huge deal, but obviously it would be a lot nicer to just load it in the chain and use it.

Subject:RE: Improve VHS Linear Track Sound Quality

Reply by: Multitech

Date:5/15/2006 11:23:29 PM

Also consider your VHS playback unit. I work frequently with transferring VHS. Some of the latest models of JVC's have serious issues with good linear playback and you will hear a background whine when no Hi-Fi track is available. This occurs on JVC's latest SR-V101US and a number of the consumer models. I trust my Panasonic AG-1980 much more when transferring linear tracks the whine is not there. Interestingly enough older JVC's(older than a few years) don't have this problem.