Extensive compressor reviews and FAQ

 
"It killed my tone and my dynamics."
I see this line pretty often. There are several factors that can cause this experience:
 
First, it really is an unfortunate reality that many compressors roll off some of your high frequencies, and our ears/minds hear that as a deadening of the tone. With units like that, the only easy solution for brighter, livelier sound is to get a different compressor. The more challenging solution would be to modify the unit you have with a better op-amp or wider-range input or output filtering, if you are experienced in that sort of work. Don't bother adding an EQ or an enhancer/maximizer after the compressor, as those devices cannot actually "put back" any frequencies that have been cut off.
 
Second, some compressors can alter your tone when you set them to heavier compression settings. If you don't like the tone you hear from your comp, try using a lower ratio and a higher threshold. How much that helps will vary widely depending on the specific unit you're using. Also, try lowering the level of the signal going into the comp- that can help because some units use the input gain to determine the threshold. I find that the majority of complaints about dead tone result from not understanding the relationship between the output level of your instrument and the threshold (sensitivity) and ratio of the pedal.
 
Another aspect of the heavy-compression problem is that a large part of what we hear/feel as "huge deep low end" is actually due to very tall amplitude spikes in the very low frequencies, because it takes exponentially more energy to make a low frequency wave "sound loud" compared to a higher frequency. If your speakers can take the resulting power spikes, then there's nothing wrong with rocking those huge wave peaks as much as you like. If you're at all concerned about blowing speakers, then strong compression (limiting) is the tool you need to use, and losing the sound/feel of a pants-flapping low end is a necessary sacrifice. But even if the speakers are not such a concern, you may like what a "medium" amount of compression does for your tone in the highs and mids, but hate what it does to your lows. That's why multi-band compression was invented; see my article about that. It's also something that can be corrected by putting an EQ in the sidechain of the comp, to make the comp less sensitive to low frequencies.
 
Most people who have had these problems with comps robbing the low end of its strength have never spent time working with either the multi-band or sidechain systems. That's a normal situation, so my point here is not to put those people down, but instead to let you know that not all comps behave the same way, and there are better tools out there than the ones you may have used before.
 
As far as "killing the dynamics"... that is 100% a result of using too much compression. Compression is all about modifying your dynamics, that's the point. But if it "kills them", for your purposes or tastes, then you've got it set too strongly. Raise the threshold and lower the ratio. Or if your pedal just has two knobs, dial back the one that controls the amount of compression. In the case of something like the Boss CS-3, you'd dial back the "Sustain" knob, and also reduce the level of the signal going into the pedal in order to raise the threshold. You may have to turn down the output volume on your bass to make that happen.
 
Part of the problem is that people expect to hear the compression working, or hear some magic improvement to their tone (extra "fatness" for example), so they turn it up until they can hear a big change. But most of the time the correct setting of a compressor is found when you can't hear it working. Extreme compression can be useful and cool-sounding in some specialized circumstances; but the vast majority of the time you'd actually benefit most from a transparent "invisible hand" keeping your levels under control without messing things up. And that requires lighter settings. If there will be any tonal improvements from the compressor, expect them to be very subtle.
 
When people post that they hate compression because they are "very dynamic players", or because they prefer to "really hear the difference between light playing and loud playing", I respond that if they were using compression properly, the audience would actually hear their dynamics even better, that in fact compression is a tool not for killing dynamics (unless you want it to) but for making dynamics even more articulate and audible. Here's how that works:
 
When playing with wide dynamics, there are two main things that "change sound" going from light touch to heavy strike: the strings, and the clipping of the amp rig (for example tube/transistor distortion/compression, speaker driver compression, and transformer sag).
 
The strings obviously vibrate differently as you play differently, and may rattle against the frets. They will make all of their tone changes completely regardless of whether you have a compressor in line--those changes are controlled entirely by your hands, and have no direct relationship to the level of the signal. You can change the volume without altering the tonal effect of dynamic playing of the strings.
 
The amp gets more or less distorted or compressed in normal operation, without necessarily having any obvious overdrive effect or compressor feature. The amp will clip/sag based entirely on the level of the signal. So for people who play tube amps loudly for example, a compressor really will have a negative impact on the dynamic sound that player is accustomed to. But for people who play clean, expecting no amp distortion, there's no impact. So my comment about making dynamics easier to hear is aimed at clean-tone playing, not clipped-amp playing.
 
Given a clean amp, with all dynamic tonal changes coming from the strings, you then have your "quiet tone" playing at a very low actual volume level, and your "aggro/strong tone" playing at a very loud actual volume level. But you want the audience to hear both of those equally well! You don't want the quiet stuff to be lost unheard, and from a practical standpoint you don't want the loud stuff to blow your speakers. Compression, done properly, brings up the audible level of the quieter playing, making it easier to hear subtle details, without taking away the "feel" and tone of softer plucking. And by reducing the height of the stronger signal peaks, you get the freedom of really digging in to the strings for an even more dramatic dynamic string tone, without as much concern about damaging your cones, and without "making" the soundman turn you down in the PA mix.
 
In other words dynamic playing is as much about tone as it is about volume, and getting the most out of your dynamic playing can mean maximizing the amount of tonal change your audience actually hears and appreciates--and that can mean reducing the changes from maximum to minimum volume, with compression.

 
 
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