Understanding Dynamic Processors (Compression)

WeissSound

Engineer
Ditto...great post.

Thanks man. I want to talk about more things you can do with compression specifically - but there's SO MUCH. Maybe some people can ask some questions and get the ball rolling.

I'm working on a mix right now that's got about 150-200 tracks, not including the reverbs, delays, and parallel tracks I will build. There's all sorts of compression all over the place doing all sorts of different things.

There's six different kick drums that all come in at different times at different patters - I'm using compression to even out the dynamics so it never feels like there's a huge variance in kick drum energy. I'm using compression to bring out the attack on some kicks, and the lows in others. I have some heavy duty compression and saturation on the bass to bring out the overtones and weight off it, while still tucking it behind the kicks volume wise. I have compression on the vocals to help them cut through the layers of synths.

brain...over...whelmed....
 

BruddAman

New member
I'm still trying to learn the ins and outs of compression. For example, things like the ratio and threshold, attack and release.It helps my vocals when they just seem kinda flat. I've also tried watching numerous youtube vids on it.Thanks for the information sharing. It is much appreciated.
 

WeissSound

Engineer
That was reallu helpful dude. Any idea what a good external compressor would be without spending too much??

Without spending too much - that means the Fairchild recreations are probably out :(

Secret weapon compressor - art tubepac - it's DEFINITELY not an all purpose compressor - it distorts in a rawkus way, that I like as a special effect.

Bang for the buck comp - Empirical Labs Distressor. I love these in a way no man should love a machine. They go about 1,500.

Art Pro VLA Mod - The company that I beta test for, JJ Audio, currently has a mod for the Art Pro VLA. It's still in beta phase, but to my ear, I think it's already ready to go.


@Bobby - I'd love hear those Fairchild clones in action!
 

ISUCK

New member
thanks for the great write up and ill be checking out ur site to learn more

do you have any tips or exercises for training our ears to hear the 'shape' more clearly?
 

WeissSound

Engineer
thanks for the great write up and ill be checking out ur site to learn more

do you have any tips or exercises for training our ears to hear the 'shape' more clearly?

Compressors are GREAT training tools.

Easiest place to start is with kicks and snares. They have pronounced attacks and decays. Use dramatic compression settings and listen to how the sound changes - try to attach words to those changes. "Round", "Sharp", "Punch", "Thick", "Spikey", whatever, make up your own lingo.

Then experiment with other instruments. Bass guitars are good - they have a slightly more complex dynamic action than kicks and snares, but overall are still pretty simple.

Vocals are the toughest, especially rap, because we are quickly reshaping our mouths - the shape actually has a lot to do with our vowels and consonants.

But listening to how things change with extreme compression settings is very informative.
 

SafeandSound

Mastering Engineer
Here is my take:

Compression does a few things :

1)It reduces the difference between loud and quiet sounds but overall reduces the level (peaks) of the sound (so you need a makeup gain control, see below)

2)It changes the sound of audio as the compression works based on time constants which affect how the tone/transients/decay of an instrument is perceived.

Threshold : Point at which the level starts being reduced.

Ratio : How much the gain is going to be reduced (input level Vs output level)

Attack : How quick level will be reduced once threshold exceeded.

Release : How quick the level will return to previous after compression

Make up gain : overall output level control.

There are other settings such as Peak and RMS detection and Hard and Soft knee but we won't deal with those right now.

Some elements of a mix may be sticking out a little so a compressor can be used to for example even out the notes in a bass line, some higher notes may poke through the mix too loudly so a compressor can even them out. (on the source track i.e. the bass guitar)

You can change the body of an instrument and it's tone using attack and release controls you could make a snare ring a touch more/give it more body and you can artificially ehhance the decay.

I would get a decent drum loop and a few old mixes you have done and set a compressor up with 5-6 dB of gain reduction and listen very carefully to the sound of instruments as the compressor controls are moved.

TOP TIP : to hear compression working start with extreme settings :

attack 1-3ms
release - 30ms
Ratio 10:1
Thresold : try - 30dB or so
Make up gain : +10dB

Anything going through this should sound pretty weirdthe words blatty, jittery and pumpy spring to mind. (kind of musically innapropriate sounding)

Armed with the above start adjustng the controls slowly and bringing them down to more mellow setting such as:

attack 10ms and release 250ms and a ratio of 3:1 as you then raise the threshold so you have around 4-6dB of gain reduction, adjust the controls and refer to what I have listed below. This will even out the peaks and troughs in your signals, do not be afraid to use the make up gain control to increase overall output level and counteract the gain reduction (lowering of peaks) which is intrinsic as compression occurs.

In addition every compressor has a unique sound which means no 2 really sound the same which also adds to the confusion, try a standard DAW plugin in Logic or Cubase, Ableton etc etc, these will probably be pretty standard (not too smooth) and you will hear the compression more easily.

Once you discover the power of compression to effect music you will never turn back !

In all likeyhood it will take time and practice to understand what compressors are capable of doing but this should give some insight.

SafeandSound Mastering
Mastering
 
Last edited:
Let's say we have some basic drum samples- kick, snare and hhat. They come from different sample packs, might as well be already compressed. We have a piano melody with triad chords and bass notes for example. It would fill most of the freq. range.
So the snare along with some C2 - C3 notes I guess would hit the redline 0dB and kick is drawn into bass sound. So we turn them drums down on fader and now it sounds like $41t.
Would you start with EQ and then compress individual sounds? Or should we compress the whole drum group?
How important is it to watch the clipping indicator when you're playing around with sounds if it sounds good on YOUR speakers at YOUR volume?
 

WeissSound

Engineer
Let's say we have some basic drum samples- kick, snare and hhat. They come from different sample packs, might as well be already compressed. We have a piano melody with triad chords and bass notes for example. It would fill most of the freq. range.
So the snare along with some C2 - C3 notes I guess would hit the redline 0dB and kick is drawn into bass sound. So we turn them drums down on fader and now it sounds like $41t.
Would you start with EQ and then compress individual sounds? Or should we compress the whole drum group?
How important is it to watch the clipping indicator when you're playing around with sounds if it sounds good on YOUR speakers at YOUR volume?

I'm not sure what $41t is - but I think I get what you are asking.

So first - hat, kick and snare, all from completely different sources. Very common. First - one has to decide if they need to sound more cohesive, or if they are tonally working together - OR - if it's even necessary for them to tonally work together.

I say this a lot, and I'll keep saying it a lot: Deciding what you want is the first move, always. If you decide the drums could all gel more, that's going to effect the specifics of your approach.

But let's step passed that and just work more generally for a moment.

Normally, I'll do corrective eq before compression - this is not a rule, this is just something that is generally true for my process. The exception being if "big tones" need a big lift. Like a boost to the low end on a kick. No point in chaining that before a compressor, because the compressor will just suck it back down.

The primary reasons for compressing a whole drum group are - a) to get things moving dynamically in a similar fashion, (b) to add a bit of the same tone from the compressor to each drum - which will make them sound more "blended" (c) to soften the drums on the way to the 2-buss if you are going for a loud mix.

Most of the compression for me happens on the individual drums.

And remember - it's not compression - it's shaping, texture, and tone.
 

SetUsAlight

New member
On my college course we were taught compression in the same kind of depth as this post- thinking about sound as a shape, as it were. Great post.

What confuses me is how little people actually pay any attention to this kind of thing. No one seems to grasp the idea of compressing with particular elements of the sound in mind- whether it's for attack or for tone. It's like, "oh hey it's a kick drum, better squash this to hell" and you end up with huge pumping sounds pissing all over a mix, vocals that are just a mess of consonants hissing away.... and they don't seem to really see it as a problem, they just approach is methodically rather than musically. Crazy.
 

RMstudio

New member
Question... When comparing microphones (ie. Dynamic vs. Condenser) What becomes important about how they compress a signal differently?
 
Last edited:

WeissSound

Engineer
Microphones have different capsule mechanism. Dynamics have a moving coil of copper wire, which compared to a gold membrane is heavy (gold membranes being the diaphragm of a condenser mic). Ribbons have a thin sheet of metal that waves back and forth in a magnetic field. These weightings yield different "actions" or responses to incoming signals. The heavier weightings will react more slowly to a signal, rounding out or absorbing moments of the initial attack - but once they get in motion, they tend to stay in motion so that attack becomes back weighted. This makes for a "heavier" sound, which on percussive instruments can sound "chompy" or "spikey" - but generally very aggressive. It's like adding a slight compressor with a fast attack, super fast release function.

A condenser on the other hand will generally be much faster moving. But because it's much lighter, it will give less resistance when it's in compression or rarefaction mode - which will generally round out the very most peaks in a signal - unlike dynamics will exaggerate the very most peaks.

Then there's the weird mics, like Royer 121s. The 121 has the ribbon on a moving docket, which is actually place slightly outside the magenetic center. Sound pressure moves the docket into the center of the field - allowing the royer to handle high levels of SPL very well. The flipside of this is that the while the initial transient will shape naturally, the greater attack portion of the signal will be slightly lower in amplitude.

Hearing what a mic does on a source, and getting to know the feel of the mic - how it reacts to transients and alters the shape, will lead to making choices. More impact, less tone, grab a dynamic - less impact, more tone, grab a condenser. Then you decide what is giving you impact and what is giving you tone.
 

NYJ

New member
thanks man :)

I've been teaching a lot these days - and I started doing mixes where I detail everything I'm hearing and doing in thorough notes - basically for the cats who don't really have the bread to have a whole album mixed, they can take my notes on the one song and apply the same ideas to the other songs. So far I'm getting a positive response.

So, I'll keep doing my best to spread the knowledge around!
How can i get this service?
 
Top