Well, I'm finally going to get around to hooking this up and have some questions about taping. Mine in a 3BX III and has Pre and Post positions for expansion. It says to use "Pre" to expand before the recording and to use "post" for most applications as it is after the recording (records, FM, etc).

My question is then: If I use pre when recording, I don't need to use post on playback as the tape has already been expanded once and to use post would double it up?

Also, is there anyway to hook this up so I can use it on 2 decks (cassette and RTR), as it only has on set of Tape connections (switchbox?). How does the Dbx 200 and 400 audio path controllers or whatever they are called work here.

Lastly, how well does the 224 work for noise reduction?

As always, TIA,

The DBX noise reduction compresses the recorded signal then expands for playback. It works very well, but in my experience the resulting tapes are best when played back on the same machine that made them. Some people do liketo play the compressed tapes in the car, I don't.

Originally posted by Andyman
[B]Well, I'm finally going to get around to hooking this up and have some questions about taping. Mine in a 3BX III and has Pre and Post positions for expansion. It says to use "Pre" to expand before the recording and to use "post" for most applications as it is after the recording (records, FM, etc).
[QUOTE]

I always thought the 3BX dynamic range expander was strictly to be used as a playback only enhancement. Considering the limited dynamic range of the analog tapes of the day, wouldn't any expansion either overload or get lost in the mud?

[QUOTE]
Also, is there anyway to hook this up so I can use it on 2 decks (cassette and RTR), as it only has on set of Tape connections (switchbox?). How does the Dbx 200 and 400 audio path controllers or whatever they are called work here.


Its been a while since I had a DBX200 switcher but IIRC they had a seperate loop for NR. It could be switched to any tape deck on the unit.

OK Andyman- excuse this short response, but it's been 20+ years since I've used a DBX system, and my memory just ain't what it used to be...

I never had much success in pre expansion- too easy to overload the cassette tapes (what I recorded on then), and they really didn't do well outside the system used to record them.

Had the best luck using the DBX on tape/analog playback, setting the level control so that most of the expansion occurred downwards- removed the residual noise floor from playback. Setting the level such that the overall output level increased led to bad sound and overdriven problems.

I was happiest with just a bit of expansion- almost more a feeling of increased dynamics rather than an easily discernable difference.

Just my input from faulty memory- only had the unit for a couple of months, traded it for other equipment. Some who owned the units swore by them, others at them.

The noise suppressor worked after a fashion, allowed some scratched vinyl to become listenable, but the unit I tried seemed to have problems separating noise and music- the more aggressive I was with noise reduction, the more music I lost along with it. JM almost 2c...Ray

Unlike Dolby if you record with DBX you must replay with DBX or the sound would be horrible:yuck:

The 3BX III is not meant to act as a noise reducing component in recording. It expands the dynamic range of the music. The III also added "impact restoration" to the mix of little miracles it could produce vs. earlier 3BX's.

That said you might choose to expand it "pre", if the source material you were recording lacked dynamics and/ or punch, e.g., FM broadcast material. But more likely you would chose post.

For reduced noise recording you'd want to compress the music (raising the level of the soft passages above that of the ambient tape noise) and then re-expand it during playback (reducing the level of the soft passages and the tape noise). dbx made stand alone processor for taping and a few tape deck manufacturers, including Akai I believe, put out some decks with dbx built in...

There were also a number of dbx encoded albums once upon a time, but that's another story...

I finally hooked up the 3BX today and found it to be quite nice; it really adds some "air" to FM, tapes and vinyl. The sound seems more open and crisp, probably "liviler" overall. The lights indicate that I'm adding about 9-12 dB of dynamic range at 30% expansion. I had to swap out the cables to my RTR, so I haven't done any taping yet, but will let all know how that turns out.

To clarify my first post, I do realize that the 3BX and 224 NR unit are two different animals. My question on taping was basically trying to find out if I could use the "PRE" setting to expand vinyl and FM prior to taping it so the recording would have expanded dynamic range. And if so, then I would not need to play them back in the "POST" mode, as the recorded signal already had been expanded.

I'll dig up some more cables tomorrow and see how it goes taping some varied vinyl.

Gotcha... As you have found, the 3BX III is a great little box. What it can do to expand material without inducing "pumping" is very nice indeed...