Mixing tip 5 – How much compression is too much compression?
There’s no actual correct answer to this unless you have completely ruined your mix with compression. Then you know the answer already… it’s obviously too much. But where, when and how much compression to use on a source is something all engineers hum and haw over during a mix. Is it for stylistic purposes? Technical reasons? Or out of absolute frustration trying to get the mix to pump, compression has so many subtle and not so subtle uses.
Sometimes you know exactly what works and other times you can find that you’re double guessing yourself. Paul Thomas a platinum selling engineer I have worked with had a very simple tip to share with me which I use to this day.
“Don’t use a compressor use a fader but when you do compress, compress a little but use a lot of compressors”
So simple but yet so effective.
Using this technique and experimenting with different types of compressors on different sound sources I have figured out great signal chains that work for me.
For instance on a bass guitar try using 2 or three compressors, the first one set it to a fast attack and fast release to catch the transients but only have it reducing the gain by about 2 dB something like a Urie 1176 works great for this.
On the the 2nd bass compressor I’ll use a slow attack and set the release as close to the decay rate of the bass note also looking at about 2db of gain reduction. I love using an LA 2 A for this purpose mainly because of it’s smooth attack and also because of it’s natural sounding release, also there’s just two knobs so you can dial in what you want very quickly with just the threshold and monitoring the gain reduction on it’s VU
For a third compressor I’ll use a tape plugin, yep a tape plugin, the original compressor! (well I could be wrong there)… however it’s great for subtle harmonic distortion and is a fantastic natural sounding compression our ears like hearing without you having to reach for attack, release and threshold settings.
(Funnily enough I’ll use a very similar technique on vocals as I use on bass)
On a drum kit sometimes I like to have a Teletronix LA 2A limiting amplifier compressing my grouped snare tracks (top mic, bottom mic and sometimes a snare room mic) by about 2 dB I find it’s slow attack smooths the snares transients without completely destroying them at this level.
I have an SSL G series bus compressor on my kick drum with a slow attack to maintain the transients (sometimes on the toms if they need to be kept in line with each other and leveling/automation hasn’t solved)
I then send all my drum channels through a parallel compressor something like a Fairchild 670, hammering the threshold, lots of gain reduction and getting loads of warm tube saturation to slam the drums and then fade up the compressed channel to a level where it’s giving me the overall desired punch.
Finally a touch of SSL G series compression just ever so slightly on the drum group to tame the remaining transients that poke out a little too much reducing them by 1 to 2 2db, almost using it like a soft knee leveler for the drum mix.
Now this is just one way of doing drums there are many more but always lots of compressors, compressing slightly (apart from the parallel which in a lot of instances I like to slam and blend, or in other instances like jazz not use at all) giving the overall effect of bigger drums.
Finally there’s my rear bus compressors and mix bus compressors.
For my Mix bus I love using the Neve 33609 set at 0db threshold, 100ms recovery, 2:1 ratio with a slow attack and adjust the gain by switching on and off bypass until the compressed signal is at parity with the uncompressed signal.
I tend to give my mixes lots of headroom before it reaches this compressor between 18-24db RMS so the compression that is occurring is often quite subtle and for smoothing purposes rather than taming anything drastically but you notice the difference when it’s turned off.
It’s great to mix into a compressor this way as long as you don’t over compress and leave plenty of headroom for the mastering engineer.
However, if you’re not comfortable with mix bus compression it’s best to let the mastering engineer work on that for you. In fact a lot of mastering engineers will request no compression at all on your mix bus so they can use their tools to sculpt the sound more but if you know what you’re doing and know what you like to hear you can add compression to your mix bus and chances are the mastering engineer won’t even notice (if you’ve done your job well that is).
A place I generally find myself experimenting a lot with compressors to find the right one for the job are as “rear bus compressors”. It’s a technique pioneered by Andrew Schepps but basically entails sending an aux signal of 0db post fader of every instrument to an FX channel I’ve assigned a particular compressor to.
So for instance I’ll have a “guitar channels rear bus compressor” that I’ll send signals of all guitars to, “All Vocals Rear bus Compressor”, I’ll send signals of all vocals to, “Brass Rear bus compressor” I send all the …you get the idea…… And finally an “Everything Rear Bus Compressor” where everything gets sent to.
I’ll experiment with a few compressors to see what fits with the song. It could be a LA3A for guitars as it seems to do something nice to the 300hz frequencies for me, an API 2500 for keys, brass and strings is great as it’s pretty clean and doesn’t trample their transients, and an LA 2A on the vocals is always a classic…It will vary track to track what compressor I use and what feel it brings to the song but for my “Everything Rear Bus Compressor” a lot of the time I usually find myself reaching for the SSL G series bus compressor.
Once again I recommend you check out this technique by Andrew Schepps and experiment with it. There are plenty of YouTube tutorials on it.
By the way all the classic gear I’m mentioning here are plugins and all these techniques are achievable, “in the box”. The tricky bit is deciding what compressors to use not how many of them as so many compressors have their own unique characteristics. If you’re new to mixing I’d recommend picking one or two compressors to begin with and learning them really well. Even the compressors that come free with DAW’s today ain’t too shabby and are a great place to start to learn the basics.
If you’re still keen on experimenting more but not sure what compressors to try, here’s an old but useful article by SOS from 2009 about classic compressors and where to use them.
And remember compress little but use lots of compressors!..unless of course you want to compress lots and use only one compressor… there are no rules once you know how to break them!