Expander

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Shanes

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Hi,

I wonder if someone could tell me a little about using an 'Expander'.....thus far I've been using it as a gate. It works OK for me but somehow I think I might be missing the point.
Thanks,

Shane
 
A Gate is a extreme version of a expander.
The gate turns soft parts off while the expander turns in down.
They are smoother rhen a gate when working with lowering levels
For example - you can use a expander to cure a bad compression job
 
Slight clarification...

"...For example - you can use a expander to cure a bad compression job..."

Not quite... with an expander you can restore *some* of the lost signal to noise ratio on an overcompressed signal, but you will never restore any of the signal attack or level peaks that got lopped-off by the compression in the first place.

Bruce Valeriani
Blue Bear Sound
 
Yes. I had only meant the dynamics and even that is only a reasonable fix not a full cure.
 
so is it only the ratio that is altered to turn a gate into an expander?? or the threshold as well?? what sort of differences are there with regard to these two settings between an expander and a gate?? im familiar with setting up a gate , just never really used it as an expander , could someone explain ??
 
Many units will have a slector button to switch between a gate/Expander.

They have the same controls just that an expander will turn the noise down rather off like a gate
 
im using a dbx 266 compressor and all it has for the gate/expander is a threshold and ratio (which only has min-max, i have another one 266XL , the gate/expander on this has a ratio control eg.1:1, 2:1.....). In order to get an expander out of it i suppose instead of having a hard cttoff ratio eg. the max setting on the 266, and 4:1 on the XL ... am i remotely close..? then i would guess by turning the ratios so it offers a slower release and attack this somehow acts as an expander.... ?? a lot of that is guessing , as im sure you can tell...
 
The term "expander" really comes from changing the S/N ratio of the signal, and has nothing really to do with compression ratio - they are two entirely different things.

If you have a heavily compressed signal - you potentially have a poor signal to noise ratio due to the fact that the compression action upped your noise floor.

You can "expand" the S/N ratio somewhat back to its orignal if you set an appropriate signal threshold (which typically would match the noise level of the signal) and apply a signal reduction of x dB at that point. If your track is the same as the noise floor - you've got a big problem but in most cases, the noise threshold is lower so you can expand the apparent dynamic range by pushing the noise floor back down - away from your signal, and "expanding" the dynamic range.

Bruce Valeriani
Blue Bear Sound
 
i was actually refering to the expander/gate section of the dbx compressor.. The compressor threshold, ratio etc.. is seperate.. So in terms of expansion of a signal what would be the typical functions of the threshold and ration knobs on the expander/gate side of the compressor? Would the threshold set the point at which expansion will begin and ratio the amount at which it will drive down the ground noise and increase the dynamic range of the peice?? what exactly is 'expansion' anyway? i spose im still a little unclear as to the differences between an expander and a gate.. I understand a gate is more of a definite cuttoff point where as an expander is a little softer?? is that close... well cheers anyway..
 
The difference between the expander and a gate is the speed of the cut-off (gate is either on/off above/below a given threshold), given an attack control - this would set how quickly the gate responds to a signal. Given a ratio control, I think what you said was correct in that it is the amount in which the gate will drive down the noise floor.

I have another expander unit that is a bit more flexible in that it allows not only a threshold setting, but also a frequency cut-off at which expansion may or may not occur - excellent for for reducing noise while still letting the signal thru... (although I guess this is more of an expander/noise reduction unit!!!)

Come to think of it, I've never seen any unit simply called "expander" - it always seems to be paired with another term (gate/noise reduction/etc..)

Bruce Valeriani
Blue Bear Sound
 
well cheers bvaleria... probly the reason there usually paired is cos, like u said , given the ratio control this gives the option of making it work as a gate or an expander .. Are there any other types of gate/expanders out there ? what about some type of multiband gate/expanders or would these be on a multiband compressor?
 
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