Possible to change HiFi mistracking sound?
 

Let me explain shortly. I've been having a problem with a Hi-Fi VCR which has a beeping/chirping type of mistracking sound audible in almost every audio, but only on the right channel. The problem is not audible in any other VCRs, just this one, but I can find the chirping located above 20kHz, so it's not audible at all on any of those VCRs.

I'm wondering, is it possible to up the up the artifact so it's above the audible range? Maybe there's a screw or something you could adjust?

Spectrogram example attached.

The audio heads can be adjusted, but you must be careful, as it can make tapes not play correctly at all.

Thanks for the jpg but could you also upload an audio sample please? Much more information to go by.

My standard first approach would be a thorough tape path clean (do you know how to do this?) and then check if manually adjusting picture tracking while playing (usually the channel change buttons on the remote) makes any improvement. LP or slower recordings are always more touchy re noise in the HiFi tracks.

@lordsmurf You mean the roller guides? I've tried adjusting those, but reverted the screw positions back, cause it just made the audio more crackly and the picture worse.
But, I hope you're talking about some another adjustment, I've never found any information on how to adjust the hi-fi heads. I'm guessing it's because it's pretty hard/impossible to do, but that's why I'm asking.


@timtape Attached a sample below.

The tape path is completely clean, cleaned with isopropyl (problem existed before cleaning too).

And I always use around 10 clicks of + tracking to reduce that artifact loudness, but it's impossible to improve it any further than those ~10 clicks.

No, not the roller guides. Audio head.

If you misclean the video heads, where HiFi is played, it will distort, crackle, etc. Damaged heads.

latreche and hodgey have discussed taps, screw twists, and pressures "fixing" malfunctioning video head cylinders causing HiFi audio noise. Look for those posts in this repair subforum.

Thanks for the audio sample.

1.The buzzing sound seems not nearly as loud as it can sometimes be.

2. The buzzing seems pretty centralised, ie: equal in left and right channels.

3. A standard audio Declick tool reduces some of the "bite" in the clicks.

4. There is more of a hiss in the right channel than the left. It's centred on about 9 kHz. Not sure if the hiss is in the original HiFi recording or in your playback chain including the VCR.

5. Your digital recording here maxes out at around 15 kHz (32 kHz sample rate?) so other artifacts above that frequency are of course missing.

6. This excerpt sounds to be the tail end of a louder musical section. We dont get to hear the loudest section of the soundtrack so hard to judge what the actual signal to noise ratio is. Subjectively the buzz/clicks are roughly equal in level to the right channel hiss which at normal comfortable listening levels, may not be too distracting. Feel free to upload another sample which presents both a very quiet section and a very loud section from the same source tape.

@lordsmurf
Thanks, will look for the posts.

@timtape
The sample shows the problem perfectly. Loud sections don't have any issues, only the quiet parts, so from sound transitions to quiet parts there is that ~9khz "tone" or "chirping" sound you can see in a spectrogram, which isn't present on any other vcrs with this same tape and other tapes as well. And I'm not bothered by the low frequency buzzing, or the white noise, but only what's in that 9khz range.

For your 4th point, that is the issue I'm talking about. The 9 khz tone, chirping or whatever you may call it is only present on the right channel ONLY when using this VCR. With another VCR, that 9khz tone gets pushed way higher up in spectrogram on the same tape, way over 20kHz, so it becomes inaudible.

So I was wondering, is it possible somehow to adjust the "default?" mistracking tone location so it's not located in 8-12kHz range, but so it sits at over 20kHz?

Yes as the music progressively fades out, the 9kHz area is progressively boosted and actually narrows in bandwidth as per my spectrogram. (The lower channel is the right channel here in my spectrograph). HiFi audio used "compansion" to lower noise, with compression in record and expansion in playback. Possibly here it's a fault in your VCR's right channel playback expander, perhaps tired capacitors which is common in older electronic gear. Not sure if it's a fault worth having a technician attempt a repair.

Sorry for forgetting to mention, but do you think the compansion step is broken if playing back tapes which were recorded on this same vcr don't have the 9kHz problem? The sample below doesn't have the line in quiet parts and also sounds just like the original to me.

Also I had already sent the VCR to repair, but they couldn't find any issues, so I just wasted 50 euros in shipping. Maybe the VCR doesn't like specific tape types or something?..(Don't know if there even are different types).

I guess if it's not fixable, I'll live with it, it's not like a denoiser can't remove this artifact, imperfectly, but good enough.

Yes this sample sounds and looks fine to me. Are you saying this was recorded on this same VCR?
If so, this is sort of to be expected. The compansion is a "mirror image" system. It's designed so that whatever the encoder does to the signal, the decoder does exactly the opposite, cancelling out the encode artifacts. But it's still non standard and will only work with recordings made on that machine.

It's unlikely to be different tapes. If the VCR is playing its own HiFi recordings OK fine that suggests the problem is confined to the VCR. The HiFi system in your VCR while working within itself, is not compatible with the VHS HiFi standard, hence the weird effect when playing a standard VHS HiFi soundtrack. If you played one of its recordings on a fully standard VHS HiFi deck I guess you would also have a somewhat weird playback, again because of the incompatibility, this time of the non standard recording with the standard playback.

Well it probably can be fixed but at what cost? If it was mine and I had other good VHS decks I'd probably still keep it and use it only for normal linear audio playback as used in pre HiFi VHS and many VHS/VHS-C camcorder recordings.

I have one more VCR - a Samsung combo machine which I use for fast forwarding and stuff for footage to do less damage to the Panasonic's heads. While it sounds worse, with sound shifting from left to right just a little bit (you can only tell that on headphones), it doesn't have that 9kHz line.
But on the NV-FS88, any audio sounds perfectly fine, even dual mono recordings have almost the same information on both channels, it's only that on certain tapes (a lot of them) there is a 9kHz mistracking line, and only that.
I made a capture of one same tape a while ago on another Panasonic Hi-Fi vcr which I don't have now. It also had mistracking - wide lines spanning from like 8 to 20kHz when there was sound, but on completely quiet parts the line shifted to over 20Khz, rather than to like 9k. And certain tapes have the line at 9khz, some at 6k, and some even at like 15kHz..

The FS88 playing audio perfectly is more a statement about the quality of certain Panasonic S-VHS decks, and not really a problem with the others.

You have to also remember that it wasn't just CRTs that were inferior, but the speakers in TVs were.

Having bass and/or treble pumped up is a modern situation. And I'm sure you're thinking, "my audio isn't pumped!" But if you were in the 1980s, what you're hearing on a modern computer is deep and loud. Audio was far more muffled, more tinny, back then. So flaws in VCRs were hidden, much like overscan was not noticed until the digital era.

So set expectations accordingly. That doesn't mean that bad/crap decks are excusable, but that tolerating some % of imperfection may be required at times.

Not sure I'd accept chirping, however. Something is wrong there.

It's quite common in the VHS linear (normal) audio track playback to hear multiple interference tones at different frequencies, which are not on the tape but added by certain playback decks, often later models. We've discussed this on the forum at times.

But it's not common in VHS HiFi. There the common issue is "pop and click" sounds, sometimes momentary, sometimes regularly repeating. So what you're describing here seems unusual and I'd not be surprised if it is mainly confined to a particular playback deck in HiFi, or particular HiFi recordings made on the same deck or camcorder.