Conference napalm::guitar

Try adjusting the RELEASE to eliminate "breathing".
Thats what it said in the manual for my Alesis unit.

Rick

    Thanks for the suggestion.  I've tried fooling with the release
    and it does help.   I've also found that once the track is mixed
    with others, the breathing is barely noticable.    Many thanks to
    everybody that replied.
    
    			TCM

	I recently bought an Audio Logic MT66 dual compressor/limiter.
	I did not get a manual with mine, but the dealer is tracking one
	down for me. My understanding of the controls is cursory, but
	her goes:


    gate - If your unit has an integral noise gate, it probably has a
	   gate control to set the level where the gate closes. Most
 	   gates cannot eliminate all noise without causing chattering
	   (breathing) of the gate itself. 

    threshold - This determines at what point the signal will be compressed.
           below threshold, the signal retains a 1/1 ratio between the 
	   input and output dynamic range. Above threshold signals get
	   compressed according to the ratio/attack/release controls.
	
    ratio - This determines how much the dynamic range is reduced. Only
	   signals above threshold will be effected. A few examples settings
	   follow

	   ratio	input			output

	   1/1		10 db above threshold	10 db above threshold
	   2/1		10 db above threshold	5 db above threshold
	   10/1		10 db above threshold	1 db above threshold
	   100/1	10 db above threshold	.1 db above threshold
	   inf./1	10 db above threshold	0 db above threshold

    attack - This determines the rising edge of the signal, and how quickly
	the compressor kicks in. 

    release - This determines how fast or slow the compressor releases as the
	signal fades. 

	Signals with quick rising edges such as drums, Bass pops, etc.
	will require a fast attack in order to track the input accurately. 
	In order to chop off the tail to keep snares, kick drums, etc 
	sounding tight, the release may also be set for a short setting.
	Instuments with a fairly smooth attack and release to begin with
	should be set for slower attacks, and releases in order to keep
	them sounding smooth, not choppy (ie. guitar, voices, etc.

    input level - This determines how hard the compressor will be driven.
	My unit has enough headroom to allow you to plug an instrument in
	directly, and drive it up to line levels. I find that if the comp-
	pressor is set for a subtle setting (ie 2/1 ratio, and slow attack
	release times) I have to drive the input slightly higher to get
	much effect out of the compressor. 

    output level - determines the final output signal level. Again my unit
	has tons of headroom. I generally keep the output right at 0db gain
	and my output is right up there at 1v line levels. 



	Musician magazine put out a special "Guide to home recording"
	a while back which covered all areas of recording including
	controlling dynamic range. They gave a very good expanation of
	how compressor/limiters work. My understanding may be flawed,
	so I suggest you look for additional info. 

	Hope this helps.

	Mark Jacques

    I've got a half a rack space and I want to fill it with a compressor.
    A comp/sustainor would be nice too, or do all compressors allow
    for increased sustain???  I know of the SRD Rockman Guitar Compressor
    for $99.95 and a friend of mine mentioned a dbx half-rack for maybe
    $120.00.  Anybody have suggestions?  I'd like to keep the cost in
    the $100 to $120 range.  Basically, I play rhythm guitar (although
    I do a few leads) and I'm looking for something to smooth out the
    sound.
    
    joe.

    Joe,
    
    In my opinion, so called compressor/sustainers made for guitar
    should be called something else because the word compressor is
    confusing. 
    
    Regular compressor (ie DBX 166, Rocktron A300, etc.) are designed
    mainly for recording use. The idea is to compress the dynamic range, 
    so that the tape will not be over saturated. Saturated tape results 
    in distortion. Actually a simple limiter would accomplish this (chops
    off any signal above a certain level which the user sets). Compressors 
    actually raise the noise floor and limit the upper end of the range, 
    so that quiet passages seem louder, and louder passages seem quieter 
    (resulting in a smoother overall track, which audio equipment can 
    handle with less distortion). This type of compressor does it's
    job as transparently as possible (depending on the quality of the
    unit). This means that the listener will hear little or no differance
    between the original sound, and the recorded sound. With a good
    compressor you can turn the compression ratio up to infinity, and
    the differance in sound is barely noticeable. 
    
    Guitar compressor/sustainers are differant animals. They are not
    designed to be transparent. In stead they are designed so that a
    very noticable differance is affected on the sound. The guitar
    squeeks more, and chords get squashed. Notes seem to hang in the
    air forever.
    
    The only rack-mount guitar compressor/sustainer I am aware of is 
    the SR&D rock module which was just released within the last 6 
    months. I have not seen them in any store, and I have to wonder if 
    they ever got off the ground with this unit. The ads I saw in GP 
    mentioned that the unit has a built-in smart gate to eliminate 
    noise. I'm not sure if the gate would eliminate noise from other 
    sources (ie single coil pickups, other noisy efx, etc), but they
    do promise that the compressor itself is noise-free.
    
    The DBX 163X is the 1/2 rack compressor you mentioned. This is
    for recording purposes, not guitar sustaining.
    
    I have a Boss stomp box compressor CS3. It sustains great, but
    it does increase the noise level of my telecaster. 
    
    You have a rock module eq, don't you. The sustainer would look
    great next to it, and the two units should work great together.
    
    GO FOR IT !!!
    
    Mark Jacques
    
    
    P.S.  What I'd like to know is what kind of compressor/effect
    George Harrison uses to get his squeeky clean slide guitar sound. 
    I'm sure his VOX AC30TB's help to produce that sweet pure sound,
    but he must have some other tricks up his sleeve.
    

RE < Note 1391.5 by ANT::JACQUES >

	I have heard conflicting statements about the differences between
compressors and limiters, and no-one seems to be able to point to any definitive
word from the manufacturers of such units to be able to clear up the confusion.

	What I've heard is that compressors and limiters are different only to 
the extent that their RATIOS of compression differ.  That is, a limiter puts an
ABSOLUTE infinity-to-1 ratio of compression on the incoming signal, whereas a
compressor can be variable from 1:1 on up.  I've been told that anything over
8:1 ratio is considered limiting.

	What I do NOT hear backed up from the manufacturer's literature is the
idea that compressors RAISE the level of quiet passages (perhaps the guitar
devices do this).

	The reason, I think, that people are under the impression that 
compressors RAISE the level of soft passages is because the range from the 
loudest dynamics to the softest when compression is used is so much smaller
that you generally turn up the compressed signal, giving the illusion of
louder 'soft passages'.

	The lines between these two types of devises get blurry in some cases.  
I own a rack mount MXR dual limiter.  It is selectable between a ratio of 4:1
and infintie to 1.  Now according to advise from people I trust that limiting 
starts at 8:1 and up, I would think that what I have is a compressor/limiter
(albeit limited to two settings).  Yet, it is called a limiter.

	Dan

	Oh, and another thing...

	I did once own a DBX 163X and it had a different approach.  You set the
level of sensitivity on it and it would compress at a CONTINUOUSLY VARIABLE
ratio.  That is, the louder the incoming signal, the more it would compress.
The softer the signal, the less it would compress.

	The DBX 463X Noise Gate worked just the opposite - the softer the 
incoming signal, the more it would squash the dynamics, and the louder the 
signal, the less it would squash.  In fact, there was a way you could gang
these two (using a stereo �" plug) that would allow the 463 to become a 163X
in slave mode.

	Dan

    
    Ok, from my experience, a limiter is a compression device that has
    a high ratio and *also* does not turn on until a relatively high threshold
    has been passed, thus it only compresses the peaks.
    
    Compressors can also be built with very *low* thresholds....examples
    are dbx and Dolby NR systems which compress during recording and
    expand on playback.  In both cases, the lower the signal level,
    the more it is boosted during recording.
    
    Guitar stomp box compressors *do* definitely boost low level signals,
    in fact they cause a considerable increase in noise because of that.
    
    There are a couple of factors involved, and expensive studio
    compressors have controls to adjust these....threshold, ratio, attack
    and decay controls let you tweak the compressor to work in a number
    of ways.  Obviously, a stomp box with one knob which adjusts how
    much "squash" you get and the other adjusts the output level has
    been simplified.  Notice that most stomp box companies now are making
    bass compressors which are optimized for bass applications, where
    sustain is less of an issue but controlling peaks is more of an
    issue.  I used a Boss CS2 on bass for awhile and hated it.  Sounds
    nice on guitar though.....
    
    							Brian
    

    I just recieved the literature from DOD on the Audio Logic MT66
    I purchased a month ago. As soon as I read through it, I will
    comment. 
    
    I also have a Boss CS3 compressor/sustainer. The CS3 has 4 knobs.
    It has Vol, Tone, attach, and sustain. I believe the attach knob
    sets the threshold, and the sustain knob sets the compression ratio.  
    This compressor gets a little noisy on high setting, especially with 
    my Tele. I am considering adding an NS2 or something comparable. 
    Whatever I add will have to fit into the BCB6 carry box. Anyone
    know if the Rocktron Hush stomp box is about the size of a Boss
    pedal, of is it bigger ?? The thing I don't like about the Boss
    NS2 is that you can't just stick it in series, you have to set up
    a loop, with your other efx in the loop. I already have a Power
    supply/master switch which sets up one efx loop. 
    
    Mark
    
    
    
                                                                
     
    

    
    The attack control on Boss CS2 and CS3 compressors is just what
    it says, it adjusts how fast the compressor kicks in, so you can
    adjust how "squashed" the attack of your notes get.  
    
    						Brian