A multiband band compressor is a cross between an equalizer and a compressor. If you look at my tutorials on Ableton’s EQ Eight and the compressor plugin, you will see that equalizers generally control the volume of frequencies and frequency bands, while compressors control the dynamics of an audio signal (manipulates the quietest and loudest parts of an audio signal).
Multiband compressors help you control the dynamic range of frequency bands. This generalist approach to audio mixing makes them suitable for mixing track groups and buses, as well as dynamic tracks.
You can use Ableton’s multiband compressor in two ways:
- Upward/downward compression – downwards compression is how most compressors are used, where any peaks that go over the threshold are brought down, while upward compression works in inverse, bringing up audio signal level that falls below the threshold.
- Upwards/downwards expansion – expansion is not commonly done when mixing, but Ableton has made it possible to expand upwards (introducing/reintroducing dynamics to audio that has been overcompressed or not spectrally dynamic) and expand downwards (increasing the distance in volume between the loudest and quietest parts of your signal – effectively gating)
Finding and Loading the Multiband Dynamics Compressor
In Ableton, the multiband compressor is called Multiband Dynamics. Here is how you use it:
Step 1: find this plug-in inside the Dynamics sub-folder in the Audio Effects folder in Ableton’s browser
Step 2: Open the compressor in your preferred track by double-clicking on the plug-in, or drag and drop it into your track
Step 3: Mix to your heart’s pleasure
Ableton has provided you with preset templates that you can use to suit your use cases, or as a base to start from. You can find these presets inside the Multiband Dynamics drop-down folder.
Pro tip! I recommend that you load a spectral visualizer before and after the multiband compressor to see what you are doing. I recommend Ableton’s Spectrum in the Utility sub-folder in the Audio Effects folder in Ableton’s browser.
To get to know what the multiband compressor is doing, it is best to know the parameters are, and what they do:
Here is where you will be able to control your audio frequencies input
On the far left, you can now control the frequency ranges in the high/low ends. You will notice that you cannot affect the frequency range in the midrange. This is because the midrange is affected by the start and end ranges of the high and low-end frequency ranges.
To the left of this, you will find the on/off switches of these frequency bands, and the solo options (marked as S) to hear what you are doing to each frequency band.
Below these controls, you will see the soft knee and Peak/RMS toggles. This is what they mean:
Soft Knee: this controls how rapidly the compression effect is activated. With a soft knee on, you will have your compressor gradually adding compression to your frequency bands.
RMS/Peak: This toggle allows you to control how this effect behaves with audio input. In Peak, the compression effect is triggered by the loudest points of your audio input, while RMS (Root Mean Square) finds the average audio signal level between the loudest and quietest parts of your audio signal, and every time the average loudness crosses the threshold, the compression activates.
This panel visualizes the frequency inputs and you can now affect the compression attack, release and threshold.
At the bottom of this panel, you will see the volume level range from -80 dB to 0 dB. You will also control the threshold level using the grey bars coming from the right side of the spectrometer using these bars as a slider.
On the right side of this panel, you will find the attack and release controls:
Attack: This controls how rapidly the compression effect activates, if you have a very fast attack, you will risk losing some transient impact.
Release: this function controls how soon the compression effects take to wear off. If you are compressing aggressively on an audio sample that has low-level noise, a long release will bring up this (undesirable) noise.
T/B/A: these parameters stand for Time, Below and Above. Time (T) allows you to control the attack and release times of each frequency band, Below (B) allows you to set the threshold and ratio below (Expand), and Above (A) allows you to control the threshold above (Compress)
Here you will find output and global parameter controls.
On the mid-right panel, you will be able to control the output level to compensate for the gain reduction you get post-compression, top-right is the universal output gain from where you will control the overall output signal after effects.
Time (Global): this parameter allows you to affect all the frequency bands’ attack and release values simultaneously
Amount: Finally, this parameter controls the mix between the original signal and the signal after multiband compression. Sometimes this blend results in a fuller sounding audio.
Tip! Once you have found a formula that works for whichever sound type, you can save the multiband compressor scene as a preset for later, to save time for the next time you find yourself mixing the same audio type. This is how you do it:
Step 1: click on the ‘floppy disk’ icon on the top right of the plug-in
Step 2: rename your preset. This preset is going to save as a .adv file in your user library>Audio Effects> Multiband Dynamics
The multiband compressor is a truly innovative tool. Though it is most effective for complex audio samples and track groups, feel free to use it in your mix and master buses to balance out your mixes. Create your custom presets to suit your production style and signature sound for easy access and quick drawing, and most of all, have fun!