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  #21  
10-12-2021, 07:42 PM
Teefer Teefer is offline
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Quote:
Originally Posted by timtape View Post
Thanks for the new audio sample. Are you sure this is linear audio recorded in EP? The high frequency response is way too good for LP or EP, and almost too good for SP. But whatever the format, the humming/ buzzing noises are unacceptable. If linear audio, we should hear the tape hiss but not those many tones/harmonics (I counted 27). You might try recording the same sample voice onto your Pana VCR as a comparison. Or even just a playback of this JVC recording on the Pana, event though there will be an azimuth error.

Screenshot attached of the spectral display.
Thanks for the reply.

I made a typographical error! It is recorded in SP. I will modify my post to reflect that typo once the edit button becomes available. I think there's some sort of timer that restricts the edit. I can only confirm it was played back using the 'norm' setting on the OSD. To me, that means the linear audio track is being played back, and it's the only OSD setting that produces this buzzing. It's also the only OSD setting available when playing back all of the tapes in my 80s/90s archive.

I will record the same sample using Panasonic and get back to you.
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  #22  
10-13-2021, 11:47 AM
latreche34 latreche34 is offline
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Here is a sample from my VCR HR-S7600AM from a home recorded tape on an unknown VCR in EP, Note that I boosted the gain slightly to make the noise more apparent, So as you can hear it sounds identical to what your VCR produced on it's own.

I don't know if this is due to filtration capacitors failure in the linear audio playback preamp or JVC stopped caring about linear audio quality at a certain point in the VHS era, I remember hearing the same buzz from CRT TV's from the speaker in the quite passages so it's clearly a blanking pulses noise leakage, I will eventually recap the linear audio section on my VCR's but not in the near future as it is not really important to me.

So even if you proceed with messing the alignment of your VCR's audio head it will not fix the noise. And yes a VCR with Dolby circuit is more devoted to linear audio quality than a VCR who's main focus is Hi-Fi audio.


Attached Files
File Type: mp3 VHS EP Speed Linear Audio.mp3 (1.27 MB, 4 downloads)

https://www.youtube.com/user/latoak34/videos
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  #23  
10-13-2021, 12:33 PM
hodgey hodgey is online now
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I'm hearing (and seeing on the spectrum) far less odd noise/interference in that clip compared to the SR-V101US clips and my XVS20 clips.
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  #24  
10-13-2021, 03:32 PM
Teefer Teefer is offline
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Originally Posted by hodgey View Post
I'm hearing (and seeing on the spectrum) far less odd noise/interference in that clip compared to the SR-V101US clips and my XVS20 clips.
The same type of noise is still audible and its level is high enough to render the recorded audio unacceptable in my opinion.
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  #25  
10-13-2021, 04:54 PM
timtape timtape is online now
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Quote:
Originally Posted by Teefer View Post
The same type of noise is still audible and its level is high enough to render the recorded audio unacceptable in my opinion.
Yes in the higher frequencies which an EP linear audio recording cannot make, the many noise bands are added by the playback deck. They will not be in the original recording.

Notice too the loss of (orange coloured) speech audio centred around 3.5 kHz. In that same area, notice how the added noise bands are now more visible (and audible) because there is no program to mask them. Probably caused by an azimuth misalignment in playback.

Both problems, the added noise and the loss of recorded signal, have contributed to weakened signal to noise ratio, as in your camcorder example.
Fixing one problem will help. Fixing both is best.


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File Type: jpg VHS linear audio EP Latreche.jpg (75.5 KB, 7 downloads)
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  #26  
10-14-2021, 10:38 PM
timtape timtape is online now
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Spectrum stills are not nearly as good as seeing them as a video clip in real time with the synchronised audio. I found out Win 10 allows mp4 video recording of what's on the PC screen. Here's an example. It's the linear audio of a VHS tape recorded off TV in '93.

I tried to highlight the two main problems we've been discussing here in the OP's JVC playback example:

1. Azimuth misalignment. Lost highs.

Near the beginning of the clip I deliberately misalign the audio head's angle and then return it to aligned. You can hear and see the effect together.


2. Noisy VCR audio playback.

At the end I deliberately pause the tape by pulling the pinch roller away from the tape. For a brief second you can see and hear only the VCR's own background noise. Without the program audio from the tape masking it, the horizontal lines - and the other random noise (blue specks) - are clearer. In an amateur camcorder recording with quiet voices, this noise from the VCR playback could totally mask those quiet voices.

The short dark section right at the end is after the VCR muted the audio when it sensed no tape movement.

Please note there is a few seconds' delay at the beginning of the video before I manage to play the file in the analyzer.



Last edited by timtape; 10-14-2021 at 11:23 PM.
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