DBX Noise Reduction Plug-in

[mampam]

Never say I didn't give ya'll something.
I just had to decode some of my old tapes from 1982-83. The were DBX Type 1 and we had just sold our two channel unit last year.
I came up with this for the Dyn 3.0 Expander/Gate and it works pretty darn well....the setting are based on 18dbfs=0dbvu.
Enjoy
DBX De-Code.tfx

I just realized I can't attach anything here.
If you would like this eamil me
[email protected]

We all need to help each other.

[Pirate Post]

I think the old DBX NR box was a straight 2/1 compression ratio with a pre emphasis curve.

[minister]

Pirata Capo is quite right. if you REALLY want to do the DBX thing, you need the preemphasis curve that it uses to get the compansion right.

there is a simple bandpass filter ahead of the entire DBX record/play back process which has a 3db roll off at 27Hz and 27kHz. essentially it is a flat +5dB between 100Hz and 1kHz. At 1kHz there is a rise to +10dB at 7kHz -- don't know how wide the Q is. Above 7kHz, there is a bell that descends from +10dB(7Hz)to 0dB at 20kHz. Below 100 Hz it rolls off to -3dB at 20Hz.

DBX 150 TYPE I AND MANUAL

[mampam]

You sir, are absolutely right. However, the problem with the emphasis curve is that it is constantly changing based on the input. What happens is that the input is fed into a separate amplifier chip this is then used to control a VCA chip which constantly shifts the threshold of the EQ curve. I found it less distracting to do a simple lo-pass filter at 12db/octive. This is just a starting point for getting us with no DBX hardware available to do a quick de-code.
Thanks for your input!

[Craig F]

would you consider posting the preset here:
http://www.digitalaudiorock.com/
it would let anyone download it with out heeding to e-mail you

[mampam]

would you consider posting the preset here:
http://www.digitalaudiorock.com/
it would let anyone download it with out heeding to e-mail you

I'd be honored to do that. I check that site all the time and have found a lot of the pre-sets very helpful.

[Bob W.]

I realize that this thread is more than 6 years old, however, if anyone is still interested in decoding dbx noise reduction using standard Pro Tools plugins, I have developed a method based on the original pre-empasis curves published by dbx.

Most of the information above is essentially correct, but incomplete. dbx noise reduction decoding requires a pre-emphasis EQ curve in the control (trigger) path of the 1:2 expander, as well as a de-emphasis EQ curve in the audio path after the expander.

Visit this webpage that I have posted to get all the details in my article:

A Method For Decoding dbx Noise Reduction Using Standard Plugins