Noise reduction question

[famous beagle]

My Audio Technica AT-RMX64 4-track uses Dobly C NR. And in the manual, it says this:

Dobly encoding is not present at the sub outputs. If you are dubbing from the AT-RMX64 to a second stereo deck, turn on the second deck's Dobly circuits.

I'm a little confused as to what this means, exactly.

FYI, this machine has no "Line Out" jacks. It only has four sub out jacks (and also tape out and two sends), so I'm assuming that you have to use two of those for mixing down. (The manual is very odd in that it shows you a bunch of scenarios for using the mixer in a P.A. situation but only a few examples using it as a recorder! And mixing down is not one of those scenarios.)

Anyway, so ... does this mean that, if I record all 4 tracks with Dobly C engaged, when I send them out SUB 1 and 2 to the mixdown deck it will be as if I hadn't used Dolby at all? Or is it just saying that it's not going to do the work for the second deck and apply NR for it?

I get a little confused with the whole NR decoding/encoding thing. I've never really taken the time to really understand what's going on.

But, for example, let's say I record 4 tracks on the AT with Dobly C engaged and then I mix down to my CPU. Will it sound the same as it did on my AT, or will it all of the sudden sound hissy as if Dobly hadn't been applied?

Thanks!

 

[The Ghost of FM]

Or is it just saying that it's not going to do the work for the second deck and apply NR for it?

Yes. Sub out jacks are aux. program buss outs. So they'll contain the raw signal that traveled through the mixer's channels and buss summing systems.

The noise reduction is the last stage before the signal goes to tape and the first circuit it goes through on playback to decode the NR process. (excluding the tape record and repro calibration circuits.)

So if you're using the AT unit strictly as a mixer for some other external recorder, you'd need to have that separate noise reduction that's part of that "other" deck to be turned on as the Dolby C circuits in the AT are for the exclusive use of its built in recorder.

Cheers!

 

[The Ghost of FM]

But, for example, let's say I record 4 tracks on the AT with Dobly C engaged and then I mix down to my CPU. Will it sound the same as it did on my AT, or will it all of the sudden sound hissy as if Dobly hadn't been applied?

If you recorded the tracks on the AT's recorder with the Dolby C on, they will automatically be decoded with the built in Dolby C circuitry whether you use the mixer's circuitry of the direct tape outputs.

Cheers!

 

[famous beagle]

Ok, thanks. That's what I thought, but I'd never seen a manual state it before. It seemed kind of unnecessary and needlessly confusing the issue.

Just heard back from AT that this machine retailed for $1695 in 1986. Does anyone know what the Tascam 246 retailed for back then? After hearing all the comparisons, I'm curious.

 

[The Ghost of FM]

Yeah, I agree. Their manual seems a bit lacking compared to a Portastudio manuals from the same era.

Not sure about the US retail price for a 246 but it was probably a bit lower then the AT, maybe by a couple hundred at the most. But I wouldn't read a whole lot into that, as TASCAM had an established and efficient production structure in place, and as such, could produce very decent gear more efficiently then a start up company making a first run product. Tooling up a factory is an expensive proposition.

Cheers!