Recurring audio thumping noise when digitizing?
 

Hi everyone,

I've been digitizing some VHS tapes for a certain time now and this audio problem just seem to occurred recently.

I can describe the glitch sound itself as a 4 times pulsating thump and it's a constant problem that is recurring at intervals of 1 min 30s'ish of the footage, for almost all the tape duration (60 min)

I've joined two samples -which I edited to make it short- of the audio containing the problem itself at 3 different time. (Note that the second wav named "denoise" is just the same audio but with high level pitched down to hear a bit more the frequency of the "pulse".)

Attachment 15351

Attachment 15352

Glitch sound like something electrical interference, am I right?

My setup (it's not perfect, due to budget) go like this:
JVC HR-S9911U > Sony RDR-HX750 > Intensity Shuttle USB > Mac laptop (running OS X El Capitan).
Everything is going through s-video cable from vcr to shuttle for video. RCA Cable for the audio

Beside owning a desktop PC running Win10, I don't own any other hardware... Main reason I wanted to digitize with a Mac is for the Prores422 codec, plus it give me the opportunity to leave the PC to do other jobs (editing, photoshop, etc) while I digitize long tape and nothing else.

I hear this problem on different kind of digitized tapes (used, re-recorded, almost new, camcorder tape...), and sometimes on other tapes there is no problem at all... It's confusing me. Is the tape the problem? Is my setup the problem? Both?

So if you have any input to where to start to look at for this problem, I'd be more than happy to hear.

What I plan to test eventually, in order is:
Plug the VCR in a different wall outlet, alone;
Plug the Mac in a different wall outlet, alone;
Clean the VCR heads;
Change the cables?;
Buy a lottery ticket, win, then buy better gear...

Thanks for everything!


I also attach the screencap of the intensity setup.

Attachment 15353

Attachment 15354

Attachment 15355

Attachment 15356

Attachment 15357

By the sound of it, it could be some external interference like from a cell phone periodically sending out a signal. I would check that no such device is close to the VCR when playing.

We can't tell you what that noise is, you are the only one that have access to the tapes, Troubleshooting is a process of elimination, start from the source and walk your way out. When you have several devices in chain you will never be able to find a solution. Isolate them by starting from the first device which would be a VCR or a camcorder.

If it's only on some tapes it sounds more likely that it's some vcr issue or is on the tapes but hard to say for sure. Does it happen with both hi-fi and linear audio, and does it happen at the same spot every time?

If it's on the tape itself, it's likely to happen at the same spot on every play (and if linear audio, e.g camcorder tape not contain higher frequencies).

If it's consistent on all tapes, next thing would be to test things in isolation as noted - does it happen when no tape is playing, when vcr audio is not connected at all, without sending audio via dvd-recorder, with a tv/headphones rather than via computer etc.

As an aside, having used the rdr-hx750 + intensity shuttle setup myself, I found using component to work better than s-video with the shuttle usb as the s-video input on the shuttle seemed to have some weird noise, but YMMV.

Could it be some vibrations of the reels inside of the cassette ? inducing it's way onto parts of the audio cirquitry ?
take a close listing near the vcr… scan the area near the vcr with a MediumWave pocket radio, for RF noise..

btw. ProRes422LT is enough for capturing VHS, saves you GPU/CPU processing time, and filesize volume. (works perfect)

Could be a fault of the Intensity Shuttle, quality of composite or component is better than the s-video input,
so component is the best way to go, (only PAL gives progressive mode option to capture) with Hifi sound switched off in the BMD driver, i found audio volume a little too low, with both channels linked i raised the volume a bit, which is a good overall volume for most tapes, With HiFi on VU bars go in to the red area (clipped)

WiFi routers, microwave ovens, anything too close. Assuming it's not baked on the tape, from record time.

Correct. :congrats:

False, nonsense. :rolleyes:

Composite is composited (see dictionary). That means the entire video signal is squashed down to a single carrier, and it is usually degraded (due to the device quality, not compositing in theory).

Component is essentially RGB, and requires processing to get there. Internally, most devices with component actually composite it first, ugly. And with NTSC it's generally tied into HD, upscale, and deinterlace. Nasty stuff.

s-video is Y/C, how the data was recorded onto the tape. That's what you want.

in case of a conflict, i had, once using s-video, s-video gave me bad picture quality with the combination of the Intensity Shuttle so this could be at fault with this BMD device, for that moment, not generally, i thought i made that clear, just read it again, quote me correctly, please.

that's odd !!! the VCR or the capture device ? that makes no sense ! you've got that straight ? explain !

Ah, okay.
No, not clear.

Now bad card processing I believe, that happens. :congrats:

But the solution is to get a better card, not degrade the video to appease a crappy card. :wink2:

I would certainly agree with the advice of using the process of elimination to find out if it's the tape, the player, etc. If it happens in the same places on the tape consistently and in more than one player (with a basic player to TV only type setup), that would seem to make it the recording itself.

I can relate my experience to the original poster with some camcorder footage I worked on years ago. It was a different format than VHS, but the point is that the camcorder had a very irritating, pulsing type noise it made every so often while recording. The sound was mechanical in nature, meaning the machine itself made the sound during recording, and the audio recording picked up that noise. In my case, the noise was much louder, and very difficult to do anything about. The 3 or 4 pulses of noise in the attached sample does have some similarity to what I experienced with said camcorder's recordings. I haven't worked on much camcorder footage to know if this is a common problem. In my case, all the tapes that were made from this specific camcorder had this consistent sound that occurred throughout every tape made by that machine.

If you find the noise is embedded in the tape and cannot be fixed by changing from say the HiFi audio to the linear audio track. It would be very tedious, but you may be able to remove the noise if you used a tool such as Audacity or Sound Forge to take a sample of that noise and then use it to try and remove/diminish that noise. It's the same kind of technique used to remove Tape Hiss by selecting a sample of the audio when there is nothing or as little other sound as possible, then have the software generate a pattern to apply to the audio you select to reduce audio that matches that pattern. I won't get into all of that here. But there are other forum posts that I used to learn how to do this with Audacity or Sound Forge.

Exactly ! the elimination process should not be that difficult, also, Davinci Resolve has some great audio editing options

Thank you all for your time and answers and sorry for the late reply. Did not have much time to test lately...

For the record, I don't have the original tape with the glitch (which I extracted the audio from the wav) ... gave it back to the owner and that's a shame I did not spot it before...

I have modified a bit my setup, distanced my VCR from other units for now. I don't own a cellphone (!Yes it's true!) but I do have some wifi devices near (keyboard, mouse, internet), I switched to wired, turned off some wifi devices and also cleaned the head of the VCR. I have digitize some tape since with no glitches...

Oh yes, I've switched to LT. Thanks.

Noted! I did some test with component, bit softer... maybe, noticed more detail in white, the black where lifted a bit.

https://cdn.knightlab.com/libs/juxta...b-6595d9b17862

I'm working with what I have... but I will definitely keep my eyes open to find better card for sure.

Some people confuse crappy with picky…. if you have no dropped frames with the IS it means you have a super steady clean video signal from the Sony, there's nothing wrong if you're using composite or component from the IS.
With your Sony, you could also do an all Blackmagic Design hardware capture, using also their semi-pro HDMI recorder(s) to SD/SSD flash storage.

Well, yes and no.

Composite as a carrier is actually not terrible. It doesn't have to be really soft, or have any real noise. Unfortunately most devices are crappy at implementing composite. And I mean like 99% here, not some lower number. I have seen very few devices in the past 30 years of doing video (at a serious level) than didn't just outright suck. Soft, noisy (dot crawl especially), etc. The root cause is probably the off-the-shelf parts that comprise most devices with composite. Few have in-house custom, thus the 1%.

So while you're right, you're also NOT going to get such things from standard mass market items like Blackmagic cards, and especially not on anything low-margin.

As always, realize I don't like this fact either. But it is what it is. I acknowledge it, I don't bury my head in the sand over it ("it's fine"), don't apologize for it (make excuses).

Composite itself is just bad, i have a Sony Bravia LCD TV, using composite is indeed crap to watch that way, component is just fine, with BMD converter to HDMI is also fine on this tv, only more detail/noise is visible, what can't be seen on a Panasonic CRT tv.