Multiband compression is a unique sort of dynamics processing for a better mix.
It’s a powerful compressor-style that may handle mixed problems you may need thought were unfixable.
However multiband compressors could be tough to understand, particularly when you try them for the first time.
Even so, they’re worth learning for the additional management they provide on sources with complex dynamics.
In this article, I’ll go through how multi-band compression works and the situations where it sounds greatest.
Let’s get began.
To get probably the most from multiband compression you need to begin with a basic understanding of how regular compressors work.
Try our in-depth guide to compression in case you need a full refresher, however, there’s the short version:
Compressors are utilized in mixing to cut back the dynamic vary of signals. Their impact makes the difference between the loudest and quietest elements of a soundless excessive. Compressors work by measuring the level of the input signal and turning it down every time it goes above a set threshold. They embrace controls to dial in the timing and depth of the level reduction impact.
Multiband compression works in a lot the identical method for a better mix, but with a twist.
Let’s dive in.
What’s multiband compression?
Multiband compression is a type of compression by which particular person frequency bands separated by crossover filters obtain different dynamics processing. Compressing particular person bands with different settings supplies more detailed management over the signal and permits the engineer to change dynamics in specific frequency areas.
If that sounds complicated, all it means is a multiband compressor is like a number of compressors in one.
Each particular person compressor solely acts on a specific set of frequencies. You select the threshold, ratio, and attack/release settings for each compressor in addition to the frequency vary it’ll have an effect on.
That’s where crossovers come in.
What’s a crossover?
A crossover in audio is a set of steep filters that divide certain frequency ranges in a signal for separate processing. Crossovers are sometimes utilized in loudspeaker design to separate ranges of frequencies for amplification by the kind of speaker greatest suited to breed them.
If that sounds technical, don’t worry. All it means is that crossover filters allow you to course of particular person frequency bands of a signal with separate settings.
In multi-band compression, you possibly can often select how many bands are used in addition to the frequencies of each crossover point.
How multi-band compression works
A traditional compressor applies the achieve reduction impact equally to the entire signal.
In case you’ve ever tried to compress a sound supply with complicated dynamics like an entire mix, you may need skilled the drawbacks of this method.
Compressing frequency bands individually is one solution to clear up it.
In truth, you would possibly already be acquainted with the most basic form of multiband compression—de-essing.
The harsh ‘S’ sounds that may present up with certain vocalists or microphone sorts occur mainly in the delicate 2.5kHz-8kHz frequency area.
This sound is known as sibilance and it could sound much louder than different elements of the vocal in a recording. Aggressive sibilance distracts listeners from the singer’s efficiency.
De-essers had been designed to assist engineers combat the effects of harsh sibilance.
A de-esser is a compressor that solely acts on the frequency band where the sibilance occurs.
By engaging the compressor and decreasing the level solely when the harsh ‘S’ sounds happen, you possibly can tame the aggressive peaks which are most distracting to the listener.
Multiband compression is an extension of this idea. A typical setup entails three bands—one for the bass, midrange, and treble frequencies.
You would possibly set the crossovers on the lowest band to act on materials up to 200 or 300 Hz. Moving up from there, the midrange band would possibly lengthen up to about 3-5 kHz.
The high band would then take over and act on the rest of the frequencies within the signal.
That is just an instance, however, you possibly can see how setting the compression in another way for these three key frequency areas may give you deeper control.
Where to use multiband compression
You can utilize multiband compression anywhere traditional broadband doesn’t. That makes it good for sources like:
- Entire mixes
- Samples with a number of instruments
- Synth patches with broad frequencies
- Dynamic vocals
To show how they can assist I’ll return to the instance of compressing an entire mix.
However, before we get too far it’s worth declaring that processing a full mix like this can be difficult.
Applying plugins to the stereo master observe of your mix is a powerful method that can make sweeping changes to the sound in a short time. In truth, it’s simple to do more harm than good when you don’t go in with a clear objective.
Preserve your mix bus processing delicate and keep away from processes that strongly have an effect on the headroom of your track like limiting.
In case you’re uncertain about master bus processing, consider leaving it out altogether and letting the mastering course of deal with it.
With that out of the way, commonplace compressors generally don’t work completely on an entire mix.
You might get the right amount to achieve a reduction on the lead instruments and vocals solely to have the compressor set off too aggressively on the kick and bass.
You could possibly merely highpass the compressor’s sidechain, however, then you wouldn’t be compressing the low end at all.
With multiband compression, you possibly can set the low band’s threshold excessive to keep away from squashing the bass, and the thresholds of the other bands decrease to attain even acquire reduction throughout the mix.
You’ll still be controlling the low end with compression, simply not a lot that the mix loses punch and influence.
Multiband compression is a complicated tool that may assist fix issues in your mix.
Its distinctive method will get you pondering in another way concerning the relationship between frequency and dynamics too.
In case your method around standard compressors and want even more positive grain control over your sounds, multiband compression might be the solution.