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OK, So I guess I just don't get compression
Old 30th May 2006
  #31
Lives for gear
 
RedWallStudio's Avatar
 

Although I feel slightly like Im jumping on a train that is blasting by at around 90, can someone explain Hard Knee or Soft Knee. I keep hearing that term, but have never had it properly explained. Thanks!
Old 30th May 2006
  #32
Gear Maniac
 
cheeky b's Avatar
 

here's an explanation http://www.astralsound.com/compressors.htm

Soft knee can often be a little more transparent - but you don't want it on if you're taming transients.
Old 30th May 2006
  #33
Gear Addict
 
rlnyc's Avatar
 

Quote:
Originally Posted by dbm
Man, what the hell....... This sucks

I was under the impression that the fundamentals were the same in all compressors and the thing that gave them their character was the extra "stuff" they introduce to the signal. You set a threshold, anything that goes above that threshold gets reduced a number of decibels dictated by the ratio. Attack was how fast it jumps on it and release was how long it holds it. Wtf, so now it sounds like Im hearing that some compressors restrict the frequencies on which they work or something? (e.g. only look at certain bands)
in an ideal world, that is, in Utopia, what you describe is what a compressor does. But nothing is a pure window. Stuff goes through wires and transformers etc.. It does not come out the same as it went in. Some people like that a lot, I being one of them.

It is not uncommon for recording engineers to use compressors as line amplifiers. Because a compressor reduces the volume on signal above the threshold by whatever ratio it is set at, it needs to make up that volume with an additional amplifier. Well, no amplifier on earth is neutral, so various compressors will impart qualities to the sound.

That is a separate issue than the issue of compressors affecting the frequencies as a result of the compression. That might happen also, and if you were to think about it deeply it would be easy to see. Take a musical instrument -- it is not a synthesizer producing pure tone, but has fundamentals and overtones which add together to give a timbre, or distinctive quality to the tone. As not all of the overtones are of the same volume, some are going to stick out more than others. When you add compression, you're going to change the relationships between the overtones and the fundamental. This is going to alter the quality of the sound much like an EQ would. Clearly it is a subsidiary effect -- when you compress something you're not looking for EQ, but you are going to get a little -- no way around it.

Is this making sense to you? There's no reason to get freaked out because you find out that compressor imparts artifacts along with its stated goal of dynamics control.

What do you mean by "stuff", anyway?

Best regards,
rlnyc
Old 30th May 2006
  #34
Lives for gear
 

Nah, what "sucked" was the fact that my initial concepts of compressor functionality were absolutely wrong. However, what "rules" is that I think all those misconceptions have been cleared up in this thread. Additionaly, I have had other concepts that I have read about reinforced here.(e.g. The bit about what compressors can do to drums *thanks ubik* )

Obviously compressors having their own "character" is a great thing. Just more colors for the palette.

While we are at it though, the concept of what a transient is has been giving me problems. Is the transient the peak in decibels? Always the loudest part of the sound? Here is the Wikipedia definition as it relates of audio *chuckle*

"A transient is a short-duration signal that represents a nonharmonic attack phase of a musical sound or spoken word. It contains a high degree of nonperiodic components and a higher magnitude of high frequencies than the harmonic content of that sound. Transients do not directly depend on the frequency of the tone they initiate."

Umm........yeah..........

Maybe easier would be to describe what the transients generally are on various instruments(snare, bass, acoustic guitar, etc..)

Finally, Ubik, Im not sure I know what you mean by this:

"too much attack and there'll be too much pop and you won't be able to push the fader enough to make things rock."

Does this mean that if you set the attack too slowly, the pesky loud transients will still be shooting through and you wont be able to turn it up loud enough before clipping? I ask because my mix volume was waaaaaaay to low because I couldn't turn it up without clipping, so compression was the recommended remedy.

Thanks
Old 31st May 2006
  #35
Gear Guru
 
u b k's Avatar
 

Quote:
Originally Posted by dbm
"too much attack and there'll be too much pop and you won't be able to push the fader enough to make things rock."

Does this mean that if you set the attack too slowly, the pesky loud transients will still be shooting through and you wont be able to turn it up loud enough before clipping? I ask because my mix volume was waaaaaaay to low because I couldn't turn it up without clipping, so compression was the recommended remedy.

i wasn't talking about clipping, although what you're referring to is common, but the usual solution is limiting. i was simply referring to the fact that, with too slow of an attack, when you push the fader on e.g. the snare, you'll get to an appropriate level but it'll be all pop and no sustain, so the drum will lack size and impact... there and gone, there and gone. if you push the fader more to bring up the sustain, there'll be too much pop and it'll sound distracting.

tighten up the attack, and the transient begins to sit more in the mix, increasing the proportion of attack to decay. it's quite a thing, finding that balance: the right attack time, the right ratio, the right threshold, and the right release, coupled with the right fader level, the right eq, the right verb, the right amount of verb, yada yada.

the good news is, there are actually a lot of "right" choices you can make. the bad news is, there are about 1000 times as many wrong ones.

enjoy the hunt!


gregoire
del ubik
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