S-VHS audio problem

[JJ47]

Hello everyone, I am new to this forum and had a question regarding an S-VHS audio issue. I recently had a local company attempt to digitize some S-VHS footage to a SSD as .avi files which I had shot for for a documentary project originally in 1992. I cannot recall the exact brand of camera used, however basic lavaliere type, clip on microphones were used to record the audio. The S-VHS tapes used were Maxell ST-126 BQ / SE-180 BQ and to the best of my recollection the footage was recorded using the highest quality recording setting of "SP" I assume as it would be commonly called.

The machine used to digitize this footage was a Panasonic AG 7750 and unfortunately there was a noticeable audio noise heard upon playing back all the footage.
The best I can describe it sounding is like a predominant electrical buzzing sound in the background, with the dialogue audio also sounding at times pretty choppy.

After shooting the footage in 1992 I remember playing it back directly from the camera on a TV and there was no noticeable audio issue, apart from some however minor electrical hum and certainly nothing to the extent of the issue heard now.

Thankfully I also made duplicates of all the footage, recording from the camera to a VCR on the same Maxell tapes, but in regular VHS recording mode.
I have been able to verify that these duplicate, VHS recorded tapes do not contain this apparent audio problem.

I am now going to contact another local company and attempt the digitization again to see if the problem persists ideally perhaps using a different S-VHS machine. If it does I will most likely then be forced to use the better sounding audio from the VHS recorded duplicates and basically try to sync it up with the S-VHS footage, as the visual portion of the S-VHS footage appears fine. From what I understand however the audio contained on the regularly recorded VHS duplicates is not in "HI-FI" mode and does sound however much perhaps somewhat comparably quieter to the S-VHS audio with the problem. Yet I am hoping that I will basically be able to sync it up in Adobe Premiere satisfactorily and even perhaps simply normalize it if needed, as again thankfully it does sound much better.

My question is whether anyone may have any good idea of what this audio issue heard playing back off the Panasonic AG 7750 in S-VHS may be attributable to? At first I assumed that it may be perhaps due to the machine itself and or possibly even the XLR cables used, however the video guy I worked with tested another customers, apparently S-VHS recorded tape (not Maxell I believe though) on the same machine and it did not seem to have any similar audio problem.

This issue is heard generally throughout all the tapes and yet is only somewhat perhaps less noticeable on a few tapes and more on others.

I stored the S-VHS tapes in a cool basement and had them rewound and along with the VHS duplicates which again do not seem to have this apparent audio issue, I have no reason to believe any of the tapes have deteriorated to such an extent as to perhaps cause this problem.

Any advice or insights to this issue would be greatly appreciated. Thank you very much.

[JVRaines]

It's probably just a tracking error on playback. VHS hi-fi audio is read by the helical scanner, so it's susceptible to tracking problems. A tech who is deaf to audio will think everything is fine because the picture looks good, when in reality, the tracking needs a small manual tweak to clean up the sound. I used to work in radio so these audio issues always stand out to me.

[JJ47]

It's probably just a tracking error on playback. VHS hi-fi audio is read by the helical scanner, so it's susceptible to tracking problems. A tech who is deaf to audio will think everything is fine because the picture looks good, when in reality, the tracking needs a small manual tweak to clean up the sound. I used to work in radio so these audio issues always stand out to me.

Thank you for this information. I initially had also generally suspected it may be a tracking related issue as well. However I became less certain after the video guy I went to then popped in another customers tape for comparison purposes which was apparently also recorded in S-VHS mode and it both looked and sounded fine without any needed tracking adjustment. So therefore I then began to assume it was something wrong with my tapes. However I am hoping it is the tracking and could perhaps be however easily fixed.

[Brad]

Wouldn't your typical Hi-Fi tracking error be crackling rather than buzzing?

At any rate, you shouldn't have to resort to synching the VHS dub-downs even if the S-VHS Hi-Fi track is unsalvageable. Just have them capture with the S-VHS linear track in that case.

[JVRaines]

I initially had also generally suspected it may be a tracking related issue as well. However I became less certain after the video guy I went to then popped in another customers tape for comparison purposes which was apparently also recorded in S-VHS mode and it both looked and sounded fine without any needed tracking adjustment.

S-VHS is a standard but every machine is just a tiny bit different. That's why there is a tracking adjustment in the first place. Nine out of ten tapes play fine on my JVC deck with automatic tracking but the tenth will require manual adjustment for the audio.

Wouldn't your typical Hi-Fi tracking error be crackling rather than buzzing?

At any rate, you shouldn't have to resort to synching the VHS dub-downs even if the S-VHS Hi-Fi track is unsalvageable. Just have them capture with the S-VHS linear track in that case.

On my deck it's more like a cyclic buzzing or sizzling. The big clue is that JJ47's audio cuts in and out, another typical symptom. If the safety dubs were made around 1992 it's highly likely that they have Hi-Fi sound which is far preferable to linear audio.

[Brad]

Oh, whoops. For some reason I read the VHS dubs as being linear.

[JJ47]

Thanks very much for everyone's input. In testing to determine what was the apparent cause of this audio issue, the video guy I did in fact notice toggle a switch on the AG 7750 from the Hi-Fi audio position downward to the normal position. Yet the audio problem still was present in both positions. However he didn't make any manual tracking adjustments at this time from what I could see. So again I am still hoping this audio issue is fundamentally due to the tracking as suggested.

[JVRaines]

You really want to avoid the linear audio track if at all possible. Its frequency response tops out around 8 kHz versus 20 kHz for Hi-Fi.