questions about compressors

[plexi12000]

what's the basic idea behind using a compressor? i just play for personal enjoyment, i dont have any 'live' experience..so there's obviously a lot of stuff i dont know! lol

i dont understand...why would you want to 'compress' your sound? thanks-

[williams485]

what's the basic idea behind using a compressor? i just play for personal enjoyment, i dont have any 'live' experience..so there's obviously a lot of stuff i dont know! lol

i dont understand...why would you want to 'compress' your sound? thanks-

It's about levelling out your sound so that any peaks in volume are compressed and any low volume sounds are amplified.  As a result of the compression, you get more sustain too.

[Transmogrifox]

Sustain is the main thing that comes to mind.  Compared to most other effects compression is subtle.

The proper term is "dynamic range compression".  It isn't like a mu-law compression used in telephone line transmission.  That kind of compression would actually sound like distortion if applied to a guitar signal.

Overall a compressor can help the sound of your guitar "come alive" on clean tones.  It can be nice also as a booster to push your amp hot channel from mild overdrive "up to 11" so you can kick it on after a rhythm section and do some nicely sustained leads.

[Fast Pistoleros]

One classic use of the compressor is for vintage guitar guitars where the pickups are older and not equal in sound output , or just low in general and a compressor helps smooth out the guitar tone amplifying the magnets equally .

Another is to help sloppy notes/sloppy playing from ringing out too much over the good stuff lol

[Mark Hammer]

1) To some extent, the history of rock is embedded in broadcast technology, and for years AM (and likely FM as well) broadcast studios used hard limiting and compression so as to not overtax their transmitters.  Recording studios used limiting to keep the tape from saturating and the phono-cartridges from being bitch-slapped.  Compression IS the sound of rock'n-roll.  Overdriven amps introduce compression of dynamic range when they clip.

2) As has been mentioned above one of the perks of compression is that it can be used to "even out" differences between levels of different pickups.  This is helpful not only when balancing different makes/brands/positions of pickups but also for balancing out the often-substantial difference in level between both coils of a humbucker, and the coil-cancelled setting of the same pickup.

3) Compression can provide a tamer and more "predictable" level for some subsequent effect.  So, for instance, it may help with a phaser that clips easily, or provide a less chaotic sweep of an envelope-controlled filter, or nail a consistent clipping tone in an overdrive pedal.

4) It's no secret that strings sound different, depending on how hard you pick/strum them.  Unfortunately, getting the tone you want from the string may obligate you to a level you don't want.  Compression will let you pick as hard or soft as you need to, and maintain the same level.

5) If one is a rhythm guitar player, backing a singer, you don't want your enthusiastic strumming to accidentally drown out or overpower the singer.  Compression lets you strum madly while singing harmony and not have to worry about  inadvertently being louder than someone else.

All in all, pretty handy.

[blackieNYC]

I have a simpler outlook on compressors: Compression is a sound effect, when it comes to guitar. Like any other.
Yes it reduces peaks, and makes two pickups put out the same level. Yes, it's output level..peaks...threshold...ratio...blah,blah.  I read about them before ever touching one.
Turns out, studio engineers use them to get "that compressed sound".  Whether it's early Mark Knopfler (rumors abound as to "which", but not "if") or those Tom Scholz Boston guitars, it's a sound effect on its own. They have become so widespread in use that engineers (most of whom understand the textbook definition) patch them up long before they take the time to see if the peaks are jumping out too much, or this drum is louder than that drum.
  Crank one up with a clean guitar, and listen to that country chicken pickin' sound.  By all means, know how it works. Experiment with different designs. They aren't all the same- but -It's just another box we step on to make the guitar sound cool. I don't see much point in thinking of it any other way.

[plexi12000]

awesome--  thank you guys for all the great explanations.  i really appreciate it.  i felt dumb for asking....but i just never knew! -lol 

so ya gotta ask to learn