Compression, Limiting, and Gating

[Michael Jones]

I think I have these three figured out, in theory at least.
In the simplest definitions:

Compression- allows for gain reduction of a given frequency response (actually, my compressor allows for gain reductions over multiple frequency responses at the same time)

Limiting- inhibits db output across a wide range of frequency responses.

Gating- allows frequencies, above and below set values to pass freely through the signal chain.

Yes?

If so, my question isn't really understanding how these work, but why you would want to use them? If an instrument is putting out a frequency, be it direct or sympathetic, why remove that frequency? It is, after all, comming from the instrument. Why inhibit that?
Where are these typically applicable?
I record a lot of solo piano, and orchestral type of music primarily in the Classical and Neo-Classical genres. Where would it be applicable in this situation?

 

[Blue Bear Sound]

None of these are frequency-related at all, unless you make it so by using a side-chain circuit, but that's another story.

A compressor's job is to change the dynamic range of a given signal. A limiter is basically a compressor set to a high or "brickwall" ratio - meaning the signal gets to a certain level, then will not exceed that point. Essentially "capping" the dynamic range.

A gate cuts off a signal below a given threshold. This can be considered an "expander" in terms of "increasing" a signal's dynamic range (as defined by the signal to noise ratio!)

Bruce

 

[Shazukura]

I'm sure there is a technical description in my manual, but I'm interested in more of a layman's explenation for this one:

what is an "enhancer"?

It's a feature on my Autocom Pro. There's a lot more to this beast than the compressor I was playing with 10 years ago... time to get out the reading glasses!

-Shaz

 

[dr.colossus]

i got my autcom yesterday, so i haven't figured it all out yet... what the enhancer does on this unit is it boosts the high frequencies on the output signal, because some of this is lost in the compression...i've got mine set on about 1.5, it can make the signal a little harsh... i like the gate on this thing, although it would be nice to have more control of the release...

 

[Michael Jones]

None of these are frequency-related at all, unless you make it so by using a side-chain circuit, but that's another story.
Bruce

HMMM,,, OK. Maybe I don't know then!
Take a look at the attachment. Note the left hand side of the graphic, see the scale along the bottom? Those are frequencies.
That's why I thought it was frequency related.

 

[EZP]

What you have here is a multiband compressor which are essentially three compressors for the three frequency BANDS. So when you set the left most compressor to a ratio of, say, 3:1 Only the bass (0 Hz to the end of this band, in your picture's case approx. 260 Hz) gets compressed (above the threshold) with 3:1. The rest of the spectrum remains untouched.
Why this technique is so usefull is still kind of a mystery to me to, as I didn't get the chance to work with ons yet. I think these babies are popular as main compressors, ie. on the main mix.

EZP.

 

[Blue Bear Sound]

Yes... exactly....

Multi-band compression is frequency-related that limits its compressor functionality to a given frequency range.

But that's not the common reference when you use the simple term compression (which implies full-frequency application).

Multi-band compression is the correct term.

Bruce

 

[Jeroleen]

Enhancer

I am no expert but...I believe an enhancer is a device that either accentuates certain harmonics or even adds certain high harmonics that tend to get lost in the recording process. I have an Aphex 204 which has an aural exciter and something called "big bottom" (I've known some women by the same name).Anyway, this seems to be what that device does. The exciter adds high harmonics and the "big bottom" adds low harmonics thereby "enhancing" the overall sound in these ranges. I have read that these devices should be used sparingly like a cooking with a special spice. you would not want to overuse the spice, put it in everything, it would simply loose its meaning or become overbearing or worse, insead of enhancing you food, it would ruin everything.

That is what I have learned so far.....

Jeroleen

 

[Shazukura]

Jeroleen,

Thanks. That helps me understand it! I'll need to mess around with my cheap cables and see what type of "effects" I can get going with it.

-Shaz

 

[MISTERQCUE]

What is an "enhancer"?

It's a feature on my Autocom Pro. There's a lot more to this beast than the compressor I was playing with 10 years ago... time to get out the reading glasses!

-Shaz

The purpose of the AutoCom's enhancer is to restore lost
freq's above 35hz when you incorporate the "SC-Filter" or
engage the limiter function of the Autocom.

 

[Lopp]

What you have here is a multiband compressor which are essentially three compressors for the three frequency BANDS. So when you set the left most compressor to a ratio of, say, 3:1 Only the bass (0 Hz to the end of this band, in your picture's case approx. 260 Hz) gets compressed (above the threshold) with 3:1. The rest of the spectrum remains untouched.
Why this technique is so usefull is still kind of a mystery to me to, as I didn't get the chance to work with ons yet. I think these babies are popular as main compressors, ie. on the main mix.

EZP.

As you noted, multiband compressors are used to compress certain frequencies while not compressing others. For example, this is useful on the main mix where you don't want your kick and bass compressing the sustain of your cymbals. Thus, your mixes are clear and clean when compressing the lower frequencies.


Matt