Question about compressor pedals

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gene12586

Member
I'm trying to incorporate my Boss Compression-Sustainer CS-3 pedal into my effects chain for my guitar playing more and more, but it still confuses me in certain respects... I think the main question is as follows: so the pedal has four knobs (level, attack, tone, and sustain)... Is the pedal already doing compression (i.e., reducing the variation between the peaks and troughs of the signal) before any of these knobs come into play, and then the attack and sustain knobs allow you to adjust the compression even more than is already being done... OR is the compression totally dependent on the knobs?

Thanks!
 
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According to this guy - it seems - the pedal is always affecting the signal even to just a slight degree with less aggressive settings. Assuming he's correct about his assertions - this is a pretty good short tutorial.

It seems that with the sustain turned counterclockwise - the pedal acts as a limiter (very high ratio). As you rotate clockwise it acts more as a compressor (lower ratios).

 
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PorterhouseMusic said:
According to this guy - it seems - the pedal is always affecting the signal even to just a slight degree with less aggressive settings. Assuming he's correct about his assertions - this is a pretty good short tutorial.

It seems that with the sustain turned counterclockwise - the pedal acts as a limiter (very high ratio). As you rotate clockwise it acts more as a compressor (lower ratios).

Click to expand...

Thanks so much for this. Very helpful.
One question: I understand what the threshold and ratio are on typical compressor pedals, but I'm not quite getting what the guy means when he says that the sustain control is actually "preamplification into the pedal to effect how hard you’re hitting the threshold".... My best guess as to what this means is that the more you preamplify the signal coming into the pedal (i.e., turn the sustain up), the more peaks (in the signal) and dynamics you’ll have with your playing (cuz you’re increasing the gain), and therefore you’re going to reach the threshold more... which I guess also implies that you’re going to have a bit less of the peaks being cut out by the compression because the peaks will be higher... Is that correct or am I way off?
 
One thing to note is that a compressor/sustainer pedal is a different animal than a standard compressor. It's also used for a slightly different purpose.
 
ashcat_lt said:
Adding gain before the compression is the same as turning down the threshold. More of the signal goes above the threshold so more of it gets compressed.
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Wait... now rethinking it...
Are you saying the threshold actually gets reduced (e.g., from 40 db to 20 db)?
 
Farview said:
One thing to note is that a compressor/sustainer pedal is a different animal than a standard compressor. It's also used for a slightly different purpose.
Click to expand...
But is it really different in practice? From what I understand, more compression gives more sustain... So it seems to me that you could just as easily call the sustain knob a compression knob.
What is the slightly different purpose you speak of?
 
no..the boss cs sustainer, is not a real downward compressor. it is an upward compressor..no ratio, hold, or release. when the sound fades it turns it up to sustain. it is a stretcher.

and....no, a limiter is a limiter.

level -to maintain gain level
tone- what is a tone circuit doing in a compressor..wtf??
attack - when it pulls up
Compression- amount of stretch..

if you get a real compressor with gain, ratio, attack, release , and hold, and a make up gain(for reductions). there is so much more you can do with it.
if you get a real limiter, you can really brickwall it. extreme knee'd to infinity and beyond.

an upward compressor is particularly awesome for vocals..it is a vocal stretch effect.

if you get a compressor, get a transformer'd one. Transformerless will sound like nothing..transparent.
 
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gene12586 said:
Wait... now rethinking it...
Are you saying the threshold actually gets reduced (e.g., from 40 db to 20 db)?
Click to expand...
No I don’t think that’s what I’m saying. This is a fixed threshold compressor. The threshold never changes. The only way to control how much compression happens is by adjusting the level of the signal going into the compression element. I was pointing out that adding gain before this fixed threshold compressor has the same effect that you might get by turning down the threshold on some other box that gives you that knob. Except…

…With a “studio compressor”, as you turn down the threshold, the final output tends to get quieter. You end up wanting to add gain after to get back closer to your original level. Some comps have automatic compensation for this. That’s not necessary with a fixed threshold compressor because you get more compression y making it louder to begin with. Then the compression makes the really loud parts less louder than the not so loud parts.

I personally don’t think of this as upwards compression. Honestly I think there’s a lot of confusion about what that term even means. This one is really just downward compression with a fixed threshold and you control the amount of compression by adjusting the gain going into it.
 
Pretty much covered above, but here's my description of the controls:

  • Level: drives the signal into the threshold. Higher level means more compression (in terms of overall gain reduction and how much of the signal is affected).
  • Attack: how fast the compression operates on a rising signal. Slower lets things like picking sounds through, faster chops off those transients.
  • Sustain: how fast the gain rises toward "normal" after the signal starts to fall. Timing this to the natural decay rate of notes and chords played on your guitar adds to the sustain. Making it faster could produce a volume swell effect.
 
a downward compressor pulls the louder sounds down to reveal the quieter ones.

a upward compressor boosts the volume of the quieting signal to sustain.

bouldersoundguy said:
the gain rises toward "normal" after the signal starts to fall. Timing this to the natural decay rate of notes and chords played on your guitar adds to the sustain. Making it faster could produce a volume swell effect.
Click to expand...
that is upwards compression, as i was told it was.


20230812_180028.jpg
 
bouldersoundguy said:
Pretty much covered above, but here's my description of the controls:

  • Level: drives the signal into the threshold. Higher level means more compression (in terms of overall gain reduction and how much of the signal is affected).
  • Attack: how fast the compression operates on a rising signal. Slower lets things like picking sounds through, faster chops off those transients.
  • Sustain: how fast the gain rises toward "normal" after the signal starts to fall. Timing this to the natural decay rate of notes and chords played on your guitar adds to the sustain. Making it faster could produce a volume swell effect.
Click to expand...
This is just not how this pedal works.

Sustain is basically gain driving into the threshold and could be called “amount”. Nothing to do with timing.

Attack actually adjusts both attack and release time.

Level and Tone come after the compression.


upward compressor boosts the volume of the quieting signal to sustain.
Click to expand...
Thats not what this pedal does. It’s a downward compressor with a fixed threshold and you can adjust the gain going in.
 
That's right, the level is the post compression trim, kind of the reverse of makeup gain. Sustain is the drive into the threshold. It's been a while since I used one. Guitar pedal compressors tend to operate like "vintage" style compressors, variable drive into a fixed threshold followed by a level control that you typically turn down the harder you drive the input.
 
I have tried three different compressors. Everytime I insert one into the chain, no matter where, different settings, I am getting feedback?
I finally just left them out of the chain. It has been quite awhile since I gave up.
 
ashcat_lt said:
No I don’t think that’s what I’m saying. This is a fixed threshold compressor. The threshold never changes. The only way to control how much compression happens is by adjusting the level of the signal going into the compression element. I was pointing out that adding gain before this fixed threshold compressor has the same effect that you might get by turning down the threshold on some other box that gives you that knob. Except…

…With a “studio compressor”, as you turn down the threshold, the final output tends to get quieter. You end up wanting to add gain after to get back closer to your original level. Some comps have automatic compensation for this. That’s not necessary with a fixed threshold compressor because you get more compression y making it louder to begin with. Then the compression makes the really loud parts less louder than the not so loud parts.

I personally don’t think of this as upwards compression. Honestly I think there’s a lot of confusion about what that term even means. This one is really just downward compression with a fixed threshold and you control the amount of compression by adjusting the gain going into it.
Click to expand...
Thanks so much! This all makes perfect sense.
 
As a follow-up question (please let me know if I should start a separate question here) - How many of you guitarists out there actually prefer to use a compressor pedal for your live stuff? I know it's much more commonly used for recording.
If you use it for live stuff, what type of live stuff do you play? And same question for those who don't use it for live stuff...?
 
dogooder said:
I have tried three different compressors. Everytime I insert one into the chain, no matter where, different settings, I am getting feedback?
I finally just left them out of the chain. It has been quite awhile since I gave up.
Click to expand...
Compressors can certainly make feedback more likely by increasing the gain of the lower volume parts of the signal.
 
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