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03-24-2020, 08:23 AM
sublimesed sublimesed is offline
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I'll admit, I don't have prosumer VCR (yet). I'm trying to determine where this audio thumping is coming from before I start spending a ton of money.

I don't seem to hear it if I connect the VCR to the TV using RCA cables, however that may just be the speakers on the TV? I've also cleaned all connectors on the VCR with Isopropyl Alcohol.

VCR
Brand: Symphonic
Model: SL2960
Output: RCA

Tape
Brand: Sony
Model: T-120VF

Capture Device
Brand: Pinnacle
Model: Dazzle DVC-100 v1.1
Input: RCA

Software
Name: VirtualDub
Version: 1.9.11
Video Codec: Lagarith Lossless
Audio Code: N/A
Audio Quality: PCM: 48000Hz, stereo, 16-bit

See Attached Video for the clip. Thanks in advance!


Attached Files
File Type: zip Audio_Thumping_Clip.zip (6.01 MB, 20 downloads)
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  #2  
03-25-2020, 08:53 PM
msgohan msgohan is offline
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Hmm. If you look at the Spectral Frequency Display, at the bottom there are little spikes with a repeating period of about 0.1 sec. I don't know the cause.

Audio_Thumping_Clip (Adobe Audition).PNG

Is it specific to this tape? Try a retail Hollywood movie release.


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  #3  
03-26-2020, 01:01 PM
sublimesed sublimesed is offline
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Quote:
Originally Posted by msgohan View Post
Hmm. If you look at the Spectral Frequency Display, at the bottom there are little spikes with a repeating period of about 0.1 sec. I don't know the cause.

Attachment 11509

Is it specific to this tape? Try a retail Hollywood movie release.
Thanks for taking a look. It's been on every tape I've tried.
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  #4  
03-27-2020, 03:45 PM
dpalomaki dpalomaki is offline
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FWIW: That low level motor-boating sort of sound I hear reminds me a bit of a low grade feedback loop I recall hearing years ago. It was a form of a relaxation oscillator.
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  #5  
03-30-2020, 04:19 PM
sublimesed sublimesed is offline
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Quote:
Originally Posted by dpalomaki View Post
FWIW: That low level motor-boating sort of sound I hear reminds me a bit of a low grade feedback loop I recall hearing years ago. It was a form of a relaxation oscillator.
Sorry, I'm not sure I follow this. Can you break this down in layman's terms?

Also, to add to this, I'm connected to a UPS however the outlet in this part of the house is not grounded. Could this be the feedback loop you are referring to?

Last edited by sublimesed; 03-30-2020 at 04:32 PM.
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  #6  
03-30-2020, 05:30 PM
dpalomaki dpalomaki is offline
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Be careful routing cables, long cables and parallel runs should be avoided as much as possible.

All devices should be connected to the same power strip. If using a camcorder as a player, try battery and then ac power to see if it makes a difference.

Eliminate all connections/cables that are not required for your process. e.g., if capturing s-video, do not connect the composite video jacks, do not connect anything to the VCR inputs, and so on.

Relaxation oscillations happen when a voltage somewhere in the system gradually increases silently, then reaches a point where it discharges creating the quick thump. The process repeats until resolved.
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  #7  
03-30-2020, 06:19 PM
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Something else near the capture workflow is causing it. Maybe same room, same house/building, or even the local power grid.

Remember to put all devices on a UPS, not directly in the wall, not on some pathetic "surge protector". (All surge protectors are junk, regardless of price, promises/marketing, or how much you like it.)

These are nice units: https://www.amazon.com/CyberPower-CP...language=en_US
Beware of the cheapest units.
Bigger units worth the cost, but mostly just gives extra battery life.

- Did my advice help you? Then become a Premium Member and support this site.
- For sale in the marketplace: TBCs, workflows, capture cards, VCRs
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  #8  
03-31-2020, 09:08 AM
sublimesed sublimesed is offline
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Quote:
Originally Posted by lordsmurf View Post
Something else near the capture workflow is causing it. Maybe same room, same house/building, or even the local power grid.

Remember to put all devices on a UPS, not directly in the wall, not on some pathetic "surge protector". (All surge protectors are junk, regardless of price, promises/marketing, or how much you like it.)

These are nice units: https://www.amazon.com/CyberPower-CP...language=en_US
Beware of the cheapest units.
Bigger units worth the cost, but mostly just gives extra battery life.
Thanks for all of the tips. I have the VCR and Computer connected to a CyberPower CP1000AVRLCD.

I guess I'm going to try to move the VCR, capture device and PC further away from each other.

Thanks again. I'll report back.
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  #9  
04-08-2020, 11:41 AM
sublimesed sublimesed is offline
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This seems to have done the trick! I moved the VCR, Capture card and PC away from each other and I don't hear it anymore.

Thanks! (CASE CLOSED)
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