Creating a Multi-band Compression/Expansion Using Pro-MB and OTT Discussion

I had the goal of creating a great multi-band compression/expansion scheme using Pro-MB. Fortunately for me, Xfer Records gives away a free plugin effect called OTT that is a three-band compressor. It performs upward and downward compression and is a recreation of the Ableton Live OTT setting  (Over the Top) in their compressor.

I like it because it gives a bright and vibrant sound quality to any track it is applied. Also, it is free.

But, I wanted more control like I can get from Fabfilter’s Pro-MB multi-band compressor. So, I set out to replicate it. I found it quite easy to get the sound I was after once you know what the OTT is doing:

  • The main function is upward compression. This means raising the levels of the quiet signals below the threshold level, bringing out the usually-quiet high frequencies. This makes a brighter sound possible.
  • Keep the lows, mids, and highs even through compression, keeping their levels consistent.
  • Lower the noise in the low-frequency range. Keep their levels down. This is known as downward expansion or gating.

There’s a link at the bottom of the page to get the free presets I’ve made.

Now, what OTT is doing is doing both an upward compression and a downward compression at the same time. I looked at my signal and what it really needed because downward compression reduces the dynamic range, I kept it only in the mids where some reduction of dynamic range is almost preferable. I looked at it like separate problems and then it is clear which function dominates in each of the three frequency bands. The low range needs clarity so reduction of the low signals in a gating-type of movement is warranted. The highs need airing out which is where an upward compression is good – signals falling below a threshold are amplified.

OTT has both upward and downward compression going on in the three different bands at the same time. Two instances of Pro-MB somehow in parallel would replicate. But, one after the other in series would be easier in most DAWs. Downward compression first would lower the peaks, then upward compression after would raise the valleys. As long as the thresholds for downward and upward do not overlap, it should work. I am wondering if the presets EDM #1, #2, and #3, included in the standard presets, had this in mind. Steve Duda says this on Reddit about OTT: “The main part of the sound is the upward compression (and the tough part to reproduce with a typical compressor) is applying (up to 36 dB but not more) of gain to a quiet (below threshold) signal. this brings up quiet detail (usually high frequencies otherwise unheard)… while also providing the typical multiband compression duty of “ironing” (consistent lows/mids/highs).”

So I didn’t make something that is exactly like OTT, but instead something that is, in my mind, a bit better. Here is what I did in Pro-MB:

  1. Applied upward compression to the high frequencies. This makes the quiet parts of the high-frequency range louder.
  2. Applied downward compression to the mids. This is the normal compression that goes on in most compressors.
  3. Applied downward expansion to the lows. This is also called gating. I lowered the levels of the quietest parts of the low frequencies. This makes for a smoother bass range without rumbles that can muddy up the bass region.

This one pictured below works quite well! It is not exactly it, but I like it a lot! (Maybe more than I like OTT.) I made more variations. See below for a link to where you can download them.

Here is a link to get the free presets I’ve made for Pro-MB that approximate the OTT sound: