Repair/Recover distant audio, remove buzzing noise

[realmrsdrjim]

I don't know if it is possible to correct my problem, but I thought I would ask folks that know more than this beginner.

I am digitizing old reel to reel tapes that belonged to my father, of a radio program he ran during the '70s. Most of them are still in excellent condition and sound beautiful, but a few appear to have started to decay. With these reels, in long sections of the reel the voice suddenly becomes "distant" or muffled, and there is a strange buzzing noise (it is not a constant level, but appears to match the the voice). When I look at the waveform, the negative half is either missing entirely or is significantly missing (note attachment - blue section is normal, then red section the problem starts).

I would like to try and recover as much of what's missing as possible, even if I could just get rid of the buzzing. It wouldn't be the same quality of audio, but at least it would be more understandable.

Any suggestions would be appreciated.

[Gale Andrews]

If the buzzing only occurs when the problem starts, and is never audible on its own, you probably cannot do much except look at an example of it in Analyze > Plot Spectrum and try Effect > Notch Filter.

If you wanted to you could upload a small audio sample, maximum 1MB (use "Upload attachment" underneath where you post) just in case someone had any ideas about playing with the phase then hearing what it sounded like.



Gale

[realmrsdrjim]

Hmm, yeah.

Thanks for your input.

I've uploaded a very short clip in case anyone can suggest anything else.

[kozikowski]

That's not a foreign signal like a buzz. That's what happens when you have intense distortion in a voice track. The voice creates its own damage. I don't know that I've ever heard an audio tape do that, but I've seen plenty of audio amplifiers do it. I wondered about your other sample, the one on the left. That one's not in too great a shape, either. I suspect what's really happening is low level voices get trapped in the distortion and higher level ones have enough volume to punch through.

That kind of damage is not typical of anything computers or interconnects do. In my opinion you need tape machine servicing. We cannot help you. There's not enough voice in the show to recover.

Koz

[kozikowski]

Just to cover the bases, you went right around the method you use to connect the tape machine to your computer. How did you do that -- in detail.

Koz

[realmrsdrjim]

Forgive if I was using a term that means something specific, I was merely using the word "buzz" in a descriptive sense.

The other sample is actually the same person speaking, within the same sentence, you can see how suddenly the problem starts: where the waveform starts to appear quite poorly is exactly where the audio starts being distorted, and the span between acceptable quality and distorted is between words. It is only a few specific reels where this is happening, and the problem is consistent on replay (same spots where the problem starts/stops). With the others the sound quality is significantly better, and the waveforms generally look healthier (though none will look/sound studio quality because this was a home-grown program).

Line-out on the tape machine to line-in on computer (yes, it is line-in not the mic jack) via a dual rca to 3.5 jack cable. I don't have a pre-amplifier to use. On the os, Line-in is set at 50% and Audacity is set to record Line-in specifically.

But, it sounds like I'm 2 for 2 saying there's nothing I can do to recover what's lost.

[PGA]

If you can hear the faulty sound when just listening to the tape playback from the tapeplayer (without recording it again into Audacity) then the problem lies in the original source and it is not going to be recoverable. You cannot recover something which isn't there. 3 for 3, sorry!

[kozikowski]

We might should gotta go back further. I have made "throw-away" copies of shows I've been involved with. They're not official and sometimes they were never checked after the show. Do you know for sure that these were the "air tapes?" They could very easily have mistakenly been produced on a broken recorder "in case I might want to listen later, but it's not important."

Koz

[realmrsdrjim]

While I haven't gone through all the reels yet, I am fairly certain they were air tapes, as the reels have type-written labels both on the box they were in and on the reel itself. There's even pen markings on the box label made by whomever actually played the reels at the station as to when they would play it.

Thanks for the responses, I appreciate everyone's time. Hopefully I won't encounter (too many) others ruined by whatever happened with these.