DIE COMPRESSION SICKNESS

[Lonesomedave]

hey guys, got yet another idiot question;

my son's guitar teacher at his school sold us a used roland cube 30 bass amp yesterday. see pic:



it has all kinds of bells and whistles, but my qx relates to the compressor function, knob second from the left on the bottom row of controls.

what exactly does it do? i mean, i think it boosts the loudness of quiet sounds and cuts the volume of loud sounds... right?

what does turning the knob do? does it boost/cut more aggressively as you turn it more?

i am sorry, but i have not had much experience with this particular effect.

any help appreciated.

[rodl2005]

You got it pretty much spot on.
That's what a comp will do. Useful for recording, to even out slapping peaks & troughs etc...
Some say they help give a punchier tone too. You usually have to adjust yr gain/vol after adjusting the comp also

[Saxn]

Yep, the farther you crank that thing to the right the more you squash the signal (less dynamic range.).

[GrowlerBox]

Check out Bongomania's website here for more than you ever wanted to know about compression/compressors.

[anonymous101511]

no, it will definitely not boost the level of softer notes, you would need a 'make- up gain' section of a real compressor to get that. This will only squash notes to varying degree.

[Ezmar]

Yup. It's exactly what it says on the tin.

Imagine a sound that has dynamic contrast, represented by the vertical axis on a graph. Compression "compresses" the dynamic content of a sound, and putting the effect higher will squash it more and more. at theoretical maximum compression, all dynamic contrast is gone, and every sound is the same volume. (That would sound like crap, though, so NOTHING does that.)

What it's used for in bass is to give it a more even sound across different notes, and sometimes to keep the volume from getting high enough to damage the equipment. Some swear by it, many do without it, but all agree that that knob should generally stay below the 10 O'Clock position. (not a hard measurement, just trying to be clever in saying that you should never use too much of it, unless you're cranking it all the way as some sort of effect.)

[Lonesomedave]

ok, i think i'm getting it.

growlerbox- will look at that site.

saxn/vail- ok, what exactly do you mean by the technical term "Squash"

/s/ Dave

[Saxn]

LOL, actually the TECHNICAL term for it is "compress" hence "compressor". All it means when you say "squash" is just what Ezmar says. Let me see if I can break it down a little more.

Say you're recording a part and it starts with a really quiet bit, and then launches into a frenzy of max volume, headbanging madness. Not all that uncommon a thing, really. So you record this part with no compressor and you listen to it... and you think "man I can barely hear that first part of the tune... we need to turn up the volume so that we can hear all the beauty and emotion that went into playing it"

So you do that, and the first part of your tune sounds simply awesome. THEN the second part hits, and your ears bleed and the speakers melt because of the increase in sound you have due to cranking the volume to hear the first part. This is unacceptable... so you need to turn the volume up first to get the light stuff THEN turn it down to keep the heavy parts in check.

This is basically what your compressor does for you. You can turn your volume up for light playing, and as you get louder, the compressor will kick in and knock off some volume for you.

...in a nutshell. There's more to it than that especially in higher end compressors, but that's the basic idea. So when we say "squash" we're talking about what the compressor does when it turns down or "squashes" the signal after it hits that loudness threshold and starts easing the volume down.

Hope that helps.

[alec]

Originally Posted by vail_bass

no, it will definitely not boost the level of softer notes, you would need a 'make- up gain' section of a real compressor to get that. This will only squash notes to varying degree.

This guy's talking about a limiter, but the Roland has a compressor which will boost quiet notes.

This is what the Roland site says

The compression effect found on the CUBE-100 BASS and CUBE-30 BASS reduces (compresses) the dynamic range of the bass sound. At moderate settings, the compression effect will "even out" the bass sound, while at higher settings it adds sustain.

[orfeu]

Not wanting to be a wise guy, and only to specify...

a limiter is nothing but a compressor working at a very high ratio.
It is not the quiet notes that are boosted in compression, but after the compressor has leveled out the louder notes by a certain "ratio", the overall signal is usually raised.
E.g. ratio 1/2: the level of all notes that are above a certain defined "threshold" is halved, result: the dynamic range above that threshold is halved, but still existant. Now you could raise the overall level and be louder without clipping!

A limiter uses very high ratio, so the level of notes above the threshold is reducedby a lot, and dynamic range is reduced to a minimum. No level peaks above the threshold.

Of course, you are right, most compressors have make up gain built in. Some raise the gain automatically which makes them sound louder and subjectively better...

So, my advice for newcomers: if comparing your clean uncompressed signal to different compressed signals, make sure you compare them at subjectively equal levels, otherwise the louder will always sound more powerful...

best
c
PS: please correct me if I'm wrong!

Originally Posted by alec

This guy's talking about a limiter, but the Roland has a compressor which will boost quiet notes.

This is what the Roland site says

[Bassmec]

Originally Posted by alec

This guy's talking about a limiter, but the Roland has a compressor which will boost quiet notes.

This is what the Roland site says

Its a compression effect therefore it has gain reduction same as a hard limiter but with a lower ratio.
Its does not turn up quiet notes it only turns down loud ones.
Make up gain is simply that, a variable gain between the compressor and the output amp.

[2400]

Owning this amp myself, I can say that it does seem to make the quieter notes louder. Emphasis on "seem". I never use it, however. I used to, but then I discovered the power of playing dynamics!

[jason poff]

It's a one knob compressor with auto makeup gain.

The further you turn the knob the lower the threshold for notes that get compressed.

The ratio will typically be affected as well.

Simultaneously, the output is increased so that the relative volume stays in the same ballpark.

Cumulative effect: Louder notes turned down, softer notes turned up, more sustain.

[Bassmec]

Originally Posted by 2400

Owning this amp myself, I can say that it does seem to make the quieter notes louder. Emphasis on "seem". I never use it, however. I used to, but then I discovered the power of playing dynamics!

In that case it must have has a dual gang pot that turns up the makeup gain as the compression turns down the loud notes more and more.
Since a real quality compressor limiter costs a great deal more than the whole combo, I would imagine its not really that great.

[jason poff]

I would imagine it's digital compression. Depending on the algorithm, it can be useful...sometimes.

[ga_edwards]

Originally Posted by Bassmec

Its a compression effect therefore it has gain reduction same as a hard limiter but with a lower ratio.
Its does not turn up quiet notes it only turns down loud ones.
Make up gain is simply that, a variable gain between the compressor and the output amp.

Strictly speaking yes, but the Roland has auto makeup gain in it's algorithm, so it does raise the volume of the quiet notes as well as compressing the louder ones. This is how most one knob compressors work.

[Saxn]

I was trying so hard to make it simple.

[jason poff]

Then why didn't you?

Your response was one of the most complex in the whole thread.

[greenboy]

Originally Posted by Lonesomedave

any help appreciated.

Roland most likely has a lot of its manuals available as downloads. Here's this one: CUBE-30 BASS :: Owner's Manual :: Roland

Now that you've heard from the guys who have the mistaken notion that since they have played with 11-knob compressors that products like this should have them too. And somehow they have missed all the products with built-in makeup gain. You'll want to get your future information from the horse's mouth versus from the horse's --

Strike that thought ; }

[Saxn]

Originally Posted by jason poff

Then why didn't you?

Your response was one of the most complex in the whole thread.

Yeah, I have to admit I have a harder time with "turning the volume down" than with "a one knob compressor with auto makeup gain" or digital compression algorithms.