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Hi Eero,  I  always prefer to have access to the original videotape and make 
my own transfer. It  sounds like an azimuth alignment/stability issue, 
possibly spacing loss, or even tape damage but cant be sure. VHS and Beta 
linear audio can be very unforgiving in this respect. Feel free to email an 
audio example.

Cheers,

Tim Gillett
Perth,
Western Australia

 ----- Original Message ----- 
From: "Eero Aro" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, April 26, 2019 12:14 AM
Subject: [ARSCLIST] A weird fading in a recording?


> Hi All
>
> My customer has a digitized audio copy from an old video tape.
> I haven't faced this kind of a problem before and cannot find a solution 
> to it.
>
> There is a fading in the high frequencies at a rate of about 1,5 to 2 Hz,
> the rate is not steady, it varies and it appears only in parts of the 
> recording.
>
> The high frequencies have been repeatedly attenuated and attenuation
> affects down to 6 kHz at places. There is high frequency content in the
> recording up to about 15 kHz.
>
> This sounds very similar to a fading interference that I heard a lot on 
> the shortwave
> when I was listening to SW bands as a radio amateur. Similar fading occurs 
> on
> medium and long waves as well. But this recording was not recorded from a 
> radio,
> it has been copied from a video tape. I don't know if the audio tracks 
> have been linear
> analog tracks on the tape.
>
> Another way I can try to describe the fading is that you would turn your 
> amplifier
> gain knob up and down, but the damping would only affect high frequencies.
>
> It is a bit like a longish "dropout" or a fade-out, but the shape of the 
> frequencies
> in the fade is different to a fade-out in a quarter inch tape.
>
> Does anyone know a way to fix this? I have tried using the Spectral Repair
> tool in RX with no success. It is difficult to define such an area, around
> which the tool could interpolate stuff into the variably shifting damped 
> area.
> Also, doing it in smaller pieces doesn't work too well.
>
> There is a screenshot of a four second sample of the spectrogram in my 
> dropbox.
> https://www.dropbox.com/s/c0n4aojd2w3ou5w/Fading%20screenshot.jpg?dl=0
>
> If anyone is interested to hear a sample of the recording, please email me 
> off-list.
>
> Eero
> ----------------------------
> http://www.tonfiks.fi 


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