Is an Overdub into a Previously Recorded Track Possible? (Teac80-8)

[xynox]

I am working with a Teac 80-8 and wondering if it would be possible to overdub into a previously recorded track just by turning down the Erase Bias? For instance if I have a guitar track already recorded, can I lay overdubs down on the same track without erasing the original?
I guess I know it works to some degree since I had to turn UP EB on several tracks in order for it to actually erase what was already there, but other than the threat of not playing properly- are there any real drawbacks?
Surely I'm not the only person to think of this but am asking you fine folks since I've never heard of anyone doing this other than by mistake.

 

[sweetbeats]

Interesting…yeah I think you could do that. Alternatively you could just bounce the pre-recorded track to a new track summed with the new source, but is this a case where you want to preserve the 1st generation quality of the original track and/or there is no track available for bouncing?

 

[rob aylestone]

We used to do that on stereo tape. In your case the snag is that you could simply switch off the erase head, and then you would simply over-record the new overdub on one of the tracks. The problem of course is that it is a one shot trick. I have never had one of those machines up close so I assume it has the usual record head that can be used as a sync head so you hear the other tracks in sync?
We used to do this on 2 tracks with a little mu-metal shield that was a push fit over the erase head that prevented it erasing the tape, but was nice and smooth and the tape just slipped over it. If I was going to do it, I would dump all the tracks to digital before I risked it. Your overdub has to be perfect, the in and out point perfect and the balance between the old and added recording has to be perfectly balanced. I don't know how you would do it other than record a demo track, then adjust the balance by trial and error, then go to the real track and hold your breath. Far too stressful for me!

 

[TalismanRich]

If it was me, I would do it with a bounce. All it takes is one screw up and the whole track is blown. The 80-8 was pretty good, especially with the DBX. You can either bounce and add to a second track, or record a second track and bounce them both to a third, so you can adjust any mix/level issues.

The success rate of doing a perfect take with perfect levels seems to be rather poor to me.

 

[rob aylestone]

I couldn't replicate it with my Tascam as it blew up last week, but I tried it on a Revox 2tr to see how easy it was to adjust balance between old and over-recorded and it's very odd. I tried first two tones, that worked pretty well, but with music it was a bit random - bass notes already on tape, loud, overshadowed everything - and quieter material (ac guitar in this case) tended to vanish. A few back and forths and the quick and dirty test convinced me it's too blunt a technique. Worst thing is that recording a dub with no audio, lowers the level that was on tape already - especially at HF. The bias current in the recording head actually erasing some of the stuff on tape.

Absolutely not something I am going to even consider - far too risky in every area.

 

[xynox]

A few back and forths and the quick and dirty test convinced me it's too blunt a technique. Worst thing is that recording a dub with no audio, lowers the level that was on tape already - especially at HF. The bias current in the recording head actually erasing some of the stuff on tape.

yes, this is what I was wondering- if it would ruin the OG recording. I was considering it mostly to emphasize some weak notes on the guitar track- nothing too technical, and seeing as 6 of the 8 tracks are already used and VOX has got to go on another, I was hoping it might be a slick way of saving tracks, but the variables add up fast and if it affects the original then it certainly isn't worth it. Maybe something worth trying on a more experimental project- suppose I'll stick to the good ol'bounce-down for now