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-   -   Mitsubishi HS-HD2000 pulsing, clicking sound on linear audio? (https://www.digitalfaq.com/forum/video-capture/12497-mitsubishi-hs-hd2000.html)

blundry 02-04-2022 10:41 AM

Mitsubishi HS-HD2000 pulsing, clicking sound on linear audio?
 
I have a Mitsubishi HS-HD2000U in pristine condition.
Picture quality, tracking, HiFi audio output, all controls and settings seem to function properly.
However, the MONO audio output generates a pulsing/clicking sound a little less than once per second.
I thought it might be mis-tracking, but the picture is very sharp and attempts to manually adjust the tracking do not alleviate the offending sounds.
Since I obtained this deck to transfer a variety of tapes to digital, it would be preferable if it could handle both HiFi and Linear Audio tracks properly. I don't really want to have to use the Mitsu for picture and another VCR for linear audio and edit together - very cumbersome workflow!
I'm hoping someone knowledgeable about this deck can suggest a likely solution.
When I first got the deck, the HiFi audio was also quite poor. At the suggestion of my tech, I had both the main board (which he said tested as being bad) as well as the audio head control swapped. This DID fix the issue with the poor HiFi audio output, but oddly, the problem with Linear Audio still remains.

timtape 02-04-2022 02:35 PM

Hi, this sounds a little unusual. Possibly an electronic fault. Are you able to upload an audio example?

blundry 02-04-2022 08:15 PM

Sample Footage with "helicopter noise" on Linear Audio
 
1 Attachment(s)
I used a brief video sample from a prerecorded film on VHS that has both HiFi and Linear Audio tracks - and you can see the on-screen menu when I'm switching audio modes.
As expected, the Linear Audio has a lot more hiss, but also produces the strange pulsing sound that I referenced in my initial post. When switching to Stereo Audio, the pulsing goes away.

To be clear, I'm not looking to digitize copyrighted material, but am using this tape to simply illustrate the issue, rather than posting footage of my family on the forum.

Some of the tapes I'm looking to transfer have HiFi tracks, and those should probably transfer ok (though I feel like I'm hearing a little loss of detail as compared to HiFi audio played on my Harman/Kardon VCD4000 VCR, which seems to have truly superior audio circuitry). But some tapes in my archive have only Linear Audio, and I obviously don't want to transfer them with this annoying pulsing noise. (The Mitsubishi, with its built-in digital filtering and TBC, produces a much more stable picture than the older H/K VCR).

I always thought that the HiFi audio is the one that is prone to mis-tracking and/or age related deterioration. So I'm perplexed why the HiFi audio sounds clean, and the Linear Audio has this pulsing sound. It isn't noise on the tape, because I don't get this noise when playing the same tape in another VCR.

Thanks for your thoughts on what is causing this issue.

timtape 02-05-2022 04:15 AM

Thanks for the sample. Linear audio mistracking normally presents as muffled audio. But this is not muffled or too badly so. The background pulsing is also not the kind of background noise we'd normally expect from a linear track.

This is further complicated because it seems the average level of the linear track is higher than that of the HiFi track, which could be an intentional decision when mastering to videocassette. Good mastering intentionally processed the linear audio signal to help disguise its limitations. Here I think I can actually hear more low level soundtrack detail in the linear track such as the adjusting of the ropes and some environmental sound than in the HiFi track (along with the expected higher linear tape noise). It's also possible the linear audio playback gain in your Mitsubishi has been misadjusted at some stage.

So hard to say just from this short section if the pulsing is due to a fault in your VCR or is on the linear soundtrack.

Does the pulsing sound in linear audio happen on a range of tapes in that deck? Can you upload the same section played on your other VCR?

blundry 02-05-2022 12:39 PM

1 Attachment(s)
I have added a second portion to the clip of my Harman/Kardon VCR playing the same portion of the tape.
Since it is a much older VCR, and lacks on-screen menus, I added titles to indicate when the audio was switched from NORMAL to HIFI.

With the H/K VCR, we have the somewhat opposite (but more expected) audio results. There is no audible pulsing on the Linear Audio track (which should be the easier audio track to read/track properly) - seemingly indicating that this isn't a pulsing noise present on the Mono track of the tape itself, but rather some misreading or distortion being generated by the Mitsubishi VCR. But unfortunately, the H/K VCR cannot be adjusted to properly track the HIFI audio on this section of this particular tape, so we hear the more commonly recognizable sounds of a fluttering noise on the HIFI track, and some break-up of the sound during the dialogue.

Of note - I wasn't intending to present this as a video comparison between the two machines - and it would be somewhat unfair to do so, because the Mitsu was set on Normal picture sharpness, while the H/K was in Edit mode, resulting in somewhat more picture detail. I suspect the Mitsu is capable of ultimately producing the better picture quality in the Sharp setting, but that is another discussion. My intention here was to try to troubleshoot the audio pulse that the Mitsu is exhibiting on the MONO setting.

I hope this provides a little more data - although I picked this section of this tape completely at random, not realizing that the H/K VCR wouldn't provide clean HIFI output in this instance.

latreche34 02-05-2022 02:00 PM

Are you talking about the pulse sound like a Helicopter? I had to put on my Sony studio headphones to be able to hear it, my laptop speakers could not resolve it. Anyway, it sounds like a bleed from the adjacent video tracks where the head switch signal is recorded but still sounded cleaner than the HK VCR, oh by the way your HK HiFi track has severe head switch interference which coincidently has the same frequency that of the interference in the other VCR's mono track from the head switch signal as well.

timtape 02-05-2022 02:48 PM

1 Attachment(s)
Thanks for the VCR comparison example. Yes on the HK linear playback the low frequency pulse on the Mitsub is gone or mostly. I count it at 10 pulses per second as opposed to the expected 30 clicks per second of the HK HiFi noise. Not sure why it should be at 10 pulses per second. Perhaps just one 10 cent capacitor is allowing an internal signal to modulate the power supply to the linear ("mono") audio amplifier, which has to amplify a very weak audio signal off the tape and was always vulnerable to audible interference electronically and magnetically.

As Latreche 34 says the pulse is quite a deep tone and low level. Probably on many cheaper speakers it wont be audible but it is there and will be most noticeable in quiet soundtrack passages on speaker systems with good bass response.

blundry 02-07-2022 10:57 AM

Thank you timtape and latreche34 for taking the time to help try to diagnose this issue.

I have to disagree that the helicopter noise on the Mitsu mono track is barely audible - particularly when compared to the H/K mono track performance. But I listened through the built-in speakers of a middling flat screen TV, as well as the amplified mini-speakers and sub connected to my computer, and in both instances found the noise very distracting. Both of these may provide greater audio detail (particularly of lower frequencies) than if listening through a small speaker on a laptop of smartphone. (Of course, the H/K HiFi performance on this particular tape is much worse - essentially unusable.)

If I am interpreting what you are each saying correctly, it sounds like there are (at least) two different theories on what might be causing this pulsing noise on the Mitsu mono track.

1) If this is a signal from the video tracks bleeding onto the mono audio track, it could be the result of a slight misalignment of the Mitsu? But given that both these decks were just serviced, maybe it is more likely that many of my VHS tapes - some of which are nearly 40 years old - have physically shrunk to where the VCR audio heads may no longer line up with the tracks on the VHS tape properly, thus causing this audio bleed from an adjacent video track? If this is true, there may be nothing at all wrong with Mitsubishi VCR - it simply may not be able to perform well on certain shrunken, mono-only recordings?

2) There could be a bad capacitor or some other hardware fault in the Mitsu that is generating the pulsing noise on the mono tracks.

I guess I have thus far been dealing with only a very small sample size. I have only attempted to transfer a few (very old) VHS tapes that lack HiFi tracks. I heard the helicopter noise on the Mitsu in Mono, but not on the H/K in Normal, and assumed that therefore there must be something amiss with the Mitsu. But I may have jumped the gun in making that assumption - it may be that there is more variability than I was anticipating in the way each machine will handle the mono audio on old, potentially shrunken tapes.

My rationale in acquiring the Mitsu D-VHS machine was that a newer VCR with built-in TBC and noise reduction was going to completely supplant my older VCR and immediately help me make flawless transfers. But that is beginning to look like wishful thinking, and in some instances, I may have to edit together picture and sound transfers from different VCRs.

I'll close by saying that what I anticipated as being a simple weekend project of digitizing some old VHS tapes of family events to preserve them for posterity has turned into months and months of contending with broken VCRs, faulty and obsolete TBC's, lost and/or dubious eBay purchases, a steep learning curve trying to educate myself about digital capture techniques and technology, joining forums, running back and forth to my local repair shop, and generally pulling my hair out in frustration. And I still don't have any captured footage that I'm happy with!

Sorry to vent, but I had no idea of the rabbit hole I was plunging down when I embarked on this project!

latreche34 02-07-2022 11:07 AM

Serviced doesn't mean anything, As a matter of the fact it could be the cause, If the VCR looses factory adjustment it could never perform as it should.

Both CR's gave mediocre linear audio performance, and the D-VHS has a better HiFi audio with no switching noise, So for HiFi stick to the D-VHS, for linear get another VCR.

lordsmurf 02-07-2022 04:52 PM

Mitsu D-VHS players have notoriously lousy audio, worse than JVCs. The playback was clearly optimized for D-VHS, and then SP mode retail playback. Not really recording, or anything not SP mode. It quickly drops off. Buzzing, humming, etc. Just lots of noise. At least with most JVCs, (usually) all you get is some hiss, though it varies on source.

If you have ancient linear audio, it's essentially a special-needs tape. Other VCRs are needed. The AG-1980 is known for audio quality, but has many other downsides. Various consumer VHS players were fine as well, though not many.

What you often have to do is capture twice: (1) video, (2) audio, and then (3) re-merge in a lossless editor.

Some people whine about "I want a single VCR to do it all, wah", but boo-hoo. (This has been a frequent gripe in the past 2 years, but not in years/decades before. Apparently too many folks are getting spoiled video-wise.) This is almost never realistic, unless you want to live with degraded audio or video. And you shouldn't be lazy like that. Even the 1980 deck isn't perfect, some tapes won't play well. It's why most of us own multiple VCRs, to handle all sorts of tapes.

Correct, "servicing" a VCR can actually screw it up, if the person was hamfisted goon that really doesn't understand VCRs. And if it came from eBay, that's a guarantee -- if serviced at all (far too many lying sellers these days).

timtape 02-07-2022 08:53 PM

Quote:

Originally Posted by blundry (Post 82632)
Thank you timtape and latreche34 for taking the time to help try to diagnose this issue.

I have to disagree that the helicopter noise on the Mitsu mono track is barely audible - particularly when compared to the H/K mono track performance. But I listened through the built-in speakers of a middling flat screen TV, as well as the amplified mini-speakers and sub connected to my computer, and in both instances found the noise very distracting...

Apologies if I gave the impression I consider the VCR's pulsing in linear audio acceptable. I dont consider it acceptable and would be embarrassed to give a customer or friend a transfer sounding like that from the possibly faulty Mitsubishi. I said the noise "will be most noticeable in quiet soundtrack passages on speaker systems with good bass response". Quite correctly you uploaded a quiet soundtrack passage, revealing the noise well.

For various reasons, linear ("mono") audio is often played back at well below its potential, making it sound weaker, often more muffled and noisier than it actually is on the tape. It takes the right VCR and skills to extract the best out of the track, and adding the least amount of extraneous noise. Obviously this is especially important when the linear audio track is the only audio track, or when the HiFi track played as well as possible, sounds worse than the linear track at its best, which can happen.

So I respect your wanting to extract the best out of your linear audio tracks. Apologies that I cant offer a quick, easy solution to that end. I regard having to play the tapes on two separate VCR's, once for the best picture and again for the best sound, as an evil necessity at best rather than a mark of expertise. Some have the expertise not to have to resort to such an expedient which involves at least twice the number of VCR's and twice the transfer time, not to mention the extra time reassembling picture and sound in post.

Of course this assumes that picture and sound should be accorded equal importance at every stage, just as the top people in film and video have always taken as a given.

blundry 02-08-2022 06:53 PM

Thank you all again, for your insights and expertise, which far, far exceed my own.

@timtape - No apologies necessary. I didn't think that you were saying that the amount of noise on the linear track played by the Mitsu was acceptable. My comment that you quoted above was more directed towards @latreche34, who indicated that he had to break out his headphones to hear it, which I found surprising, because to me the "helicopter noise" was both very evident, extremely distracting, and enough to render the transfer unusable.

More experimentation with a greater variety of tapes seems to be called for, in order to truly determine if there is a misalignment issue, or a mono amplifier/capacitor issue with the Mitsubishi. Or if I'm just dealing with a few ancient, shrunken, "special needs" mono-only tapes that are causing the problem. It is also clear that my local repair tech did not test the Mitsu in mono, because he would have needed the remote control to access the menu to switch between Stereo and Mono. And shortsightedly, I hadn't given him the remote, for fear it might get misplaced. So even if he checked the alignment (which is a big if), and/or has the skill necessary to adjust it properly, to the extent that anything related to the linear audio performance requires separate adjustment or alignment, that would have assuredly have been neglected without his having the remote to switch the deck to mono.

The point about the lack of reliable technicians is well taken. I felt fortunate to find a local repair shop that will still work on VCRs at all, as the shops I have used in the past for other a/v gear all have a strict no-VCRs policy! So beggars can't be choosers. There may be better technicians, but then I might have to subject VCRs to being shipped to and fro for repair work. The dangers of doing so probably outweigh the advantages of the more skilled repairmen!

@lordsmurf - I actually read almost all the posts I could find regarding the Mitsubishi HS-HD2000U on this forum and elsewhere, before committing to buy one. Alas, nowhere did I find any criticisms of its audio performance. True, I got it mostly because it has been praised for its digital video features - TBC, Noise Reduction, Comb Filter, etc. It is also simply a generation or two newer than many other high quality VCRs, because D-VHS appeared when VHS media was losing significant traction in the marketplace. I actually preferred the idea of getting a studio editing deck for transfers, as opposed to a consumer VCR, but so many of the studio decks look like they've been dragged from a speeding car or unearthed on an archeological dig. So I tried to make the best choice based on what was readily available to me.

As an aside, I did pick up a Hotronic AP41 TBC, which was a piece of old studio gear. I assumed it had likely been decommissioned from a broadcast facility, or perhaps a college media lab. Imagine my surprise when I found a sticker on it indicating it had come from Folsom State Prison! That TBC did some hard time in the big house! Sadly - and somewhat unsurprisingly - I couldn't get it to give consistent results when hooked to a consumer VCR - even though in theory it doesn't require an external sync generator. It does seem to work, but at a certain point during each transfer, it appears to lose frame sync, and the image either exhibits noticeable vertical jitter, or one can see the flicker of the frame line bouncing vertically through the image. I could not seem to adjust this out, but I have no scope, nor any idea what I'm doing when messing with phase and picture position pots. This was me trying to economize and hoping for the best, as I'm still struggling with the idea of paying $2500 for a time base corrector. But with all the time I've been wasting trying dozens of times to digitize the same material, and being displeased with the results, I am contemplating biting the bullet and just spending the money. Interestingly, the Hotronic did pass consistent video to my Canopus capture device, resulting in no dropouts, lost frames, or capture interruptions, something that the built-in TBC in the Mitsu cannot accomplish.

Yes, I had naively hoped that the Mitsubishi would do everything I asked of it - clean, sharp picture, great sound on stereo and/or mono tracks, consistent tape handling, no need for external full-frame TBC, and no need for repairs. None of these things have actually proven to be true. The picture stability is great, but I'm not convinced the image is as clean or sharp as it could be - that a byproduct of the built-in digital filters and TBC is a softer image.

As I said above, I feel like accomplishing clean transfers of a small collection of VHS tapes has gone from a weekend project, to a months-long thesis, to what now feels like it is becoming a full-time vocation. I do applaud all of you for your helpful advice, without which I would feel even more lost than I do now.

timtape 02-08-2022 07:53 PM

Quote:

Originally Posted by blundry (Post 82692)
...More experimentation with a greater variety of tapes seems to be called for, in order to truly determine if there is a misalignment issue, or a mono amplifier/capacitor issue with the Mitsubishi...

You should find on many commercial pre recorded VHS tapes a silent section at the beginning or end. The 'helicopter" sound if it's from your Mitsub should be very apparent.

Quote:

Originally Posted by blundry (Post 82692)
It is also clear that my local repair tech did not test the Mitsu in mono, because he would have needed the remote control to access the menu to switch between Stereo and Mono...

Normally VHS HiFi VCR's only switch to HiFi in the presence of a HiFi recording. They default to "mono".
A good tech should know this and be able to test both HiFi and linear without a remote.

As for shrunken videotape, I'm not sure. It's not a subject I've seen discussed, but shrunken movie film is a commonly understood problem.


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