dbx NR tips

  • Thread starter Thread starter lo.fi.love
  • Start date Start date
lo.fi.love

lo.fi.love

Functionally obsessed.
Hey folks,

I thought I'd start a thread with tips on using dbx noise reduction. Please join me and add your own!

So, I noticed something interesting about dbx noise reduction causing compression errors. Remember that dbx NR compresses the incoming signal, and it is prone to causing nasty compression errors if not used carefully.

For example, I'm working on a piece which uses a series of 1/6th second-long tones, coming out of a keyed gate, peaking at -3dBu. When these "beeps" are sent into the dbx unit and onto the tape, monitoring on the playback head shows that I'm causing the compressor in the dbx unit to clamp down really hard on the signal, and it makes an unpleasant "pop" or "thump". Turning dbx off on that channel and relying on tape compression instead produces a very pleasant, smooth, sorta 'soft knee' compressed sound.

On tracks with intermittent surges in volume, regardless of peak level, dbx nr will add nasty compression artifacts. Turn NR off and just EQ the playback signal to taste instead of relying on noise reduction to remove tape hiss.

Anybody else? :)
 
Good topic Lo fi,

Something that would get us off on the best start is to list the equipment and formats, including tape speed and dbx model or Type used.

dbx has issues, but they effect some dbx types more than others;

Questions
1. What tape deck
2. What tape formulation
3. What speed tape travel in ips
4. What Type dbx NR,,, Type-1 or Type-2?

We have to get this basic stuff together before we can observe it in a working system. Much can go wrong by not understanding the different dbx types. For example: dbx 150X is a different animal than the dbx 140X..

So, whataya got? :)
 
Awesome idea for a thread, Cory!;)

Also, keep in mind that head alignment is crucial in encoding/decoding the dbx signal.:cool:
 
Now that I think about it Tim, isn't Type I dbx for 15 ips, and Type II is for 7.5 ips and slower?:confused:

...or do I have that backwards??:eek:
 
Beck said:
Questions
1. What tape deck
2. What tape formulation
3. What speed tape travel in ips
4. What Type dbx NR,,, Type-1 or Type-2?
Click to expand...

My example:

1. Tascam 48
2. EMTEC SM911 (new old stock)
3. 15ips
4. dbx type I, via Tascam DX-4D
 
I used dbx (actually a Bel Electronics clone) with a Tascam 80-8 in my demo studio about 30 years ago.

It behaved fantastically if I kept the levels below saturation (I always kept an eye on the peak indicator LEDs on drum tracks), but one instrument it just couldn't handle was the lowly Tambourine. Similarly to lo.fi.love I always found that it generated unpleasant low frequency artifacts on that instrument, so I simply switched it out on that track.

Regards


David
 
I agree wholeheartedly about the tambourine being a tough instrument for dbx to handle--in fact just about anything really transient-heavy and percussive sounded a little weird to me when recorded with DBX (even when using very conservative levels).

To be honest, I don't really like DBX NR at all (I'm definitely in the minority here on that point). I've tried both the built-in units with my ms16 and external 150x units that came with my 58-OB.
Lately, I've been using alternate means of noise reduction, including
1) hitting the tape a bit harder (When I have time, I like to record a little bit monitoring off the repro head to see how hot the level can go before it saturates, then back off a little).
2) compressing a bit to tape (this can be a huge help)
3) using a subtle gating after the fact on quiet tracks (I love the sound of slightly expanded nylon string guitar)
4) boosting the treble to tape where appropriate (a high shelf on a snare for instance)

Unfortunately, 3 out of 4 of these things require patient musicians. I guess that's a big plus for dbx NR--if you don't have time to get your gain staging perfect, you can err on the side of caution and not get burned too badly.

I also have to concede that Wharton Tiers recorded some amazing albums using dbx NR (Imperial FFRR by Unrest for example, and *I think* part of Dinosaur Jr's You're Living All Over me plus many others) at Fun City in NYC. According to a Tape Op interview, he used a Tascam MS-16 then upgraded to a Tascam MSR24 (the latter, he said, compared favorably to Sonic Youth's Studer 2" 16-track).
 
Pink Floyd's "Animals" was recorded using dbx. Always sounds pretty good to me.

Regards


David
 
Sometimes I'll record bass guitar with and without noise reduction and then when I turn the NR on the one I recorded without it will pump a lot and I'll blend em to taste and it gives a cool pulse to the recording. Not sure if that's totally on topic but its a cool NR trick nonetheless!

-Barrett
 
Assuming tape machine and dbx units are individually and collectively properly aligned, all one needs to do for a clean signal with no nr artifacts is to print light. The more transient-laden the source, the less gain you need to use.
 
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