What does this mean and how do you achieve it? apparently you can increase the apparent dynamic range of your audio? I've never heard of this? Would someone be so kind as to enlighten me?

Yes most compressors can expand. Its in the ratio like this 1.1:2 will expand. 2:1 will compress. I wouldn't use the word downward though. It is both. The low parts get lower the high parts get higher. dbX use this principle for a noise reduction unit a long while back You record with high compression and playback with expansion. The overall noise is less because the highly compressed audio is recorded hot.

C:

Good for you that John posted first and said it all very concisely.

As John said DE is used to reduce noise and hiss. Essentially bringing lower passages down lower. Kepex and Drawmer gates are examples of outboards that do DE



Drawmer Link Here for more info


-D

Yeah, I just read the term recently reading about Bias's GateEx plug can do it as well...so it has what effect on audio? Whats an example of a situation you want to use this?

Can you say popular CDs LOL. No I thought I gave an example of one way to use it. Its the opposite of compression. Recorded audio is by its nature compressed. No recording has the same dynamics as a live performance. Expansion can put back some of that. Our ears don't clip. But recorded audio can.

Expansion can be both upward or downward. The main idea for using it is to increase the difference between low level and high level signals. Since noise generally dominates in low level signals expansion's main use is in increasing the signal-to-noise ratio. Upward expansion takes signals above a threshold and increases their level by a set ratio. Downward expansion takes signals below a threshold and decreases them by a set ratio. Downward expansion is very similar to a noise gate with an adjustable gain reduction setting except that with a gate the signals below the threshold are reduced by a set amount rather than a ratio.

I have never seen one that was a "downward" expander. Just expanders.

CLICK HERE to see one.

It says a gate. LOL Heck I have a gate. But is not an expander. The dbX 266.

RANE makes a gate with gate, duck, and downward expansion modes: http://www.rane.com/g4.html

They have a description of the process here: http://www.rane.com/note1555.html

Gates and downward expansion are very similar. A normal gate is a downward expander with an infinite reduction ratio (any signal below the threshold turns to silence). Like a compressor with infinite ratio is a limiter.