Hey Beck

  • Thread starter Thread starter Herm
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Herm

Herm

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Ok I know im lazy but I hope someone can answere this so I dont go to all the trouble of hooking up the machines.
My question is If I have a tape on my 38 that was recorded with dbx and I record it into my 388 with out dbx turned on on neither machine and then when I play it back on the 388 with the dbx turned on, Will it decode the dbx that was recorded on the 38 tape.
I hope that makes sense.
 
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I havne't tried it with DBX, but I would expect its a bad idea not to "deprocess" on playback and then "reprocess" on record. The compression circuitry on the two different units is likely to treat the source material differently, and while it doesnt matter if you compress/ expand with the complemenatry circuits in one machine, there will be differences between two machines.
Aslo you would seem to be losing the noise reduction advantage going to the second machine; that is you don't "compress' going in, so you are actually amplifying the second machines noise on playback.
Doea this make sense??
 
I think if you avoid the temptation to crank up the recording levels on the Studio8 when you do the transfer and keep things around -3vu on the meters, it should decode decently on playback.

If you do go too strong or too weak on the transfer level, you will screw up the 0vu swing point and the transfer may pump and breath more so then if you left both dbx nr systems on.

Try out a test experiment of half a song to see how sensitive it is..or isn't. ;)

Cheers! :)
 
Herm,

That’s a great question. I think you may be the one telling us if it works or not. :)

I’ve never tried it, but here are some thoughts. I’m assuming that the tape was recorded at 15 ips with dbx type I (DX-4D?)

The objective is to take a tape that was encoded on a 38, copying it with dbx off to a 7” tape on the 388 and then using the dbx decoding of the 388 to accurately decode what was originally encoded on the 38. (Say that three times fast) ;)

1. We know that we can take a dbx encoded tape made on one machine and play it back on another identical machine also with dbx, such as 38 to 38. But that would be the original tape rather than a copy.

2. I think if we were making a copy from one 38 to another odds are it would work pretty well.

3. Since we are going from a machine that is very different spec wise than the other there could be some issues. The 388 is running at 7.5 ips and has a frequency response that tops out around 16 kHz. While the 38 is running at 15 ips and tops out around 20 kHz. Since dbx is a broadband compander I’m wondering how the decoder on the 388 will react to frequencies that it can’t reproduce. What I’m saying is that the encoding for frequencies above 16 kHz will be copied but the frequencies themselves won’t. It may not be a big deal if there isn’t much information above 16 kHz anyway.

Both machines use dbx Type I, but the different speeds could also be an issue. The dbx companding process is much less forgiving on machines running at slower speeds. The process at 7.5 ips has to pass a tighter tolerance. In fact, dbx initially did not recommend using Type I on anything running less than 15 ips. Tascam successfully did it anyway, but it was accomplished by tweaking the hell out of systems running at slower speeds. So I’m thinking that the encoding that looked just fine to the 38 being laid down at 15 ips will look somewhat sloppy on the copy to the decoder on the 388 – maybe.

So my guess is it will kind of work, but any artifacts commonly attributed to dbx, such as pumping/breathing, misstracking etc, may be exaggerated.

Ghost already mentioned the levels, which will be critical to any success, if it’s doable.

Now take some vitamin B, Ginseng and a few cups off coffee to jolt yourself into mad scientist mode so you can tell us how it works! :D
 
Ok I got the recorders hooked up today and transfered the song like I mentioned and it seemed to work pretty well. I just took and pluged the line outs of the 38 into the line in of the 388 and set all faders to unity.
Here is a sample of the song I transfered. This song is not done so dont get to bent about the mix.

Click on Bend me on this page and it should play.
Thanks for the suggestions guys

http://mysite.verizon.net/resopl6x/
 
I'd say it works. Sounds good -- Great job Herm!

That's good information that a lot of folks will be able to use. It should work going the other way too, maybe even better, and between other machines with dbx.

Someone is probably asking about now, “Why not just transfer with dbx engaged on both machines?”

Bass frequencies around the “head-bump” tend to build up with dbx on during bouncing or transfer. Although the official line from dbx was to leave NR on while bouncing a lot of people back in the day felt it sounded better (more open) to bounce with dbx off. It worked fine when bouncing internally on something like the 246 or 388.

Also if you have a 38 or other machine, but no dbx modules, and want to transfer a dbx encoded tape, this would be a way to do it.


-Tim :)
 
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Herm said:
Ok I got the recorders hooked up today and transfered the song like I mentioned and it seemed to work pretty well. I just took and pluged the line outs of the 38 into the line in of the 388 and set all faders to unity.
Here is a sample of the song I transfered. This song is not done so dont get to bent about the mix.

Click on Bend me on this page and it should play.
Thanks for the suggestions guys

http://mysite.verizon.net/resopl6x/
Click to expand...
Damned hippies! :mad:



:p
 
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