2B or Not 2B: That Is the Multiband Question
By Jonathan Wyner
When asked about multiband compression I usually hesitate, look at the person asking the question, and try to understand the context for the question since multiband compression (or multiband tools in general) are not for every occasion.
"They change the sound in a way that may or may not have anything to do with your reason for using them in the first place."
The question then becomes – could you achieve your goals with a broadband/full spectrum application of compression? If the answer is yes, then great, do THAT! Why? Because the signal path is simpler… and therefore ‘better.’ The technology required to split bands and crossover networks of passband filters changes the audio… so just by invoking a multiband tool you change the sound before adding any compression.
"A multiband compressor is really a mash-up of two ideas: dynamic range control and tone control."
I don’t plan to go into great depth describing the impact that adding subtle distortion and phase shift can have on your audio, but suggest you do some listening on your own using the following steps:
1. Pull up a mix or a full frequency stem/track and instantiate a multiband tool with at least two bands, keep the tool in bypass.
2. Adjust the crossover point between low and mid bands to be somewhere in the neighborhood of 200 Hz.
3. Using an equalizer, boost the energy around 200 Hz 3-4 dB with a medium Q (around 2 or 3) observing the way in which the sound changes…then bypass the EQ.
4. Now enable the multiband tool and listen for a change in the area where the crossover is implemented. Turn it on and off several times and compare the sound. Do you hear a difference in tone? A change in clarity and ‘solidity’ in the sound around 200 Hz?
I suspect you’ll notice some sort of difference. So, this is an aspect of using multiband tools. They change the sound in a way that may or may not have anything to do with your reason for using them in the first place… for instance adding compression, so that’s interesting!
"For my money, the coolest thing about multiband compression is that you can tailor the attack and release times to the signals in each band."
But about multiband compression, which is what you were asking about in the first place, there are some really great things about it.
Probably the greatest is the ability to tailor the amount of compression in various bands to control the tone. Have a ballad vocal that sometimes gets too sharp when the singer leans into the hottest, emotional part of a performance? A compressor that can compress harder around 3 kHz can keep that region in check while allowing the body, warm and high end of the vocal track to stay forward. How about a mix where the kick and bass need to be glued together a bit, but the rest of the mix doesn’t need much or any compression. Or how about a mix that could use a little compression, with a bit more density in the midrange than the high and low end? These are just a few examples of when a multiband compressor is the best approach.
Reading the paragraph above you probably get the idea that a multiband compressor is really a mash-up of two ideas: dynamic range control and tone control. Pretty cool.
"Did I hear you ask about dynamic EQ"
But for my money, the coolest thing about multiband compression is that you can tailor the attack and release times to the signals in each band. Having longer attack times in the low end helps maintain the low end punch of a mix while faster attack times in the high end keeps the sharp high hat or strong sibilance from poking out too much… and conversely a fast attack in the low end keeps the kick in check in a mix while a longer attack in the high end lets the high transience stay sharp and clear. And if you want to squeeze a mix a little harder with compression without hearing the sound get too squashed (going for a loud track, eh?) then multiband is just the tool for you!
The choices depend on the sound you’re after. So, tell me more about what you are thinking and then we can decide if multiband is the right tool for the job…
Oh, and did I hear you ask about dynamic EQ…? Maybe another time.