Limiters and Compressors

[johnb820]

Does anyone have any basic tips for applying limiters and/or compression if at all? I have no idea how these kinds of things work other than that you can boost the volume of your track at the detriment of some of the dynamics. Hard limiters can result in very harsh scratchy sounds depending on what you use it on because you are literally altering the wave by cutting off the peaks at certain amplifications. I am also vaguely aware of artists applying compression to kick/bass in order to get a tighter sound. I hear a lot of trance artists do this on typical trance pads to get the trademark "trancey" leads. You can get your bass line or any part of your track to sort of "dip" around the kicks or whatever you want and boost the overall volume but I would have no idea how to properly do this.

 

The thing I worry about is that doing this would make it much harder to mix because maybe there are steady peaks at an appropriate db but you hear something completely different.

[Panoptes]

The basic parameters of compressors/limiters are threshold, ratio, attack, and decay. Compression kicks in when the amplitude of the signal going into the compressor surpasses the set dB threshold. The attenuation of the signal above the threshold is reduced by a fraction determined by the ratio parameter. The only difference between compression and limiting is that limiting usually has a ratio at or above 1/10 . Attack affects how fast the compression is applied once the threshold is hit. Decay determines how long the compression will continue when the signal falls below the threshold. Most compressors also have a side-chain option which allows one to route an additional channel's signal into the compressor. This signal's amplitude then affects the amount of compression applied to the output.

Compression is useful because it gives you control over the dynamics of the signal. For example if you apply a low pass filter to a signal rich with harmonics it will attenuate as the cutoff decreases due to the removal of frequencies. Applying compression will allow you to turn the filter cutoff frequency down and maintain a steady signal. The attack/decay parameters changes how the compression affects transients of a signal.

Just try not to over do the compression and you'll be good. You don't want your mixes to look like sausages.

[Padmapani]

nice explanation panoptes.

 

i'd like to add a few practical tips:

 

first and most important: always do a A/B comparison when using a compressor (at least while you're still in the phase of figuring out how to use it properly). use the makeup gain to get them to a comparable loudness (if you apply it to shape the transients) or signal level (if you use it to maximize the impact of your kick for example, which i don't really think is a thing you should focus on/spend your time with), and listen to the one after the other. best with eyes closed without knowing which is which. be sure to choose the variant that sounds better and not the one, where you spent a lot of time tweaking compressor settings .

 

don't use the compressor to correct things that can be corrected in a synth. there was a time when i did this way too often - with absymal results

 

for a lot of purposes (such as transient shaping, also sidechaining) it's important to let the compressor return to zero before the next note triggering the compressor hits.

a good starting point is a gain reduction by the compressor by about 3db, then tweak it from there.

if you hear artifacts ("pumping") then your compressor either has a too short release, too short attack, or you're using a too high ratio.

for "staightening out" sounds i'd like to put through a gate afterwards, i usually use long attack, release and a soft knee (meaning there's a smooth transition from no compression to maximum compression depending on the loudness of the signal - as opposed to a hard knee where compression goes from 0 to max once the threshold is crossed).

 

whenever in doubt use gentler settings (higher threshold, longer release, lower ratio) or omit the compressor enirely. no compression is always better than badly used compression.

 

know what you want to achieve and don't use a compressor just because others use it. and please never ever make the silly mistake of putting a compressor/limiter with far too agressive settings over your entire mix. that way your breaks and the first kicks in a section will be way too loud with the rest of your track being squashed into a tasteless mush. there are too many examples of this on soundcloud

[johnb820]

Thank you for the tips guys! I really appreciate it. I guess it will just take some practice and a lot of guessing.