Sound Layering: An intro to the Combinator

Layering sounds is a basic and old technique to turn any chord, bass or lead lines into a more harmonically complex, interesting and/or bigger and wider sound.

Electronic instruments are no exception to this. Some were even designed  from the ground up with this as a key feature.

MIDI helped this technique, allowing musicians to easily play more than one synth simultaneously out of the same controlling keyboard, achieving that same layering effect even with those instruments that weren’t capable of playing different sounds (i.e. patches/presets) at the same time on their own (i.e. weren’t multi-timbral).

On early versions of Reason, one could achieve this layering of sounds by duplicating the same MIDI track and assigning those tracks to drive different instrument layers, but fortunately, since Reason 3.0, there’s a more compact and elegant solution:

The Combinator!

Well, actually, before the Combinator, there was already a Reason instrument that allowed something as close to the above but only with samples: The NN-XT Advanced Sampler.

Also, maybe a little known fact about recent Reason versions, we’re allowed to add the same Control Surface (i.e. MIDI Controller) multiple times, each instance pointing to the same MIDI input Port and then, lock those various instances to various rack instrument devices.

This gets you, in the end, a similar “layering” as MIDI slaving a bunch of instruments to build those layers.


But, enough tricks and workarounds, let’s jump right into two simple ways to quickly and easily achieve this through the Combinator:

Basic Patch Layering

Method 1: Starting from scratch

1) Create a Combinator CombinatorCreate CombinatorEmpty

2) Add a Mixer inside, to mix the various instrument outputs into the Combinator output


If you’re planning to layer more than 6 sounds (Instrument devices/patches) you’re better off with the Mixer 14:2, else the Line Mixer 6:2 is a fine choice.


3) Add below the mixer, inside the Combinator, the Instrument patches you’re interested to layer:

CombinatorInstrumentAdd CombinatorInstrumentPatchAdd

4) Keep adding the Instrument devices/patches you want, inside the Combinator below the Mixer and Reason will automagically manage the audio cable routings needed (pressing [TAB] will toggle the rack view between front and back)


5) When finished and after doing any tweaking to the added patches you find necessary, it’s always a good idea to collapse (minimize/fold) the devices. You can do this by clicking the little triangle/arrow at the top left corner of each device or do it all in one go by holding the [ALT] (Windows) or [Option] (Mac) key while clicking that triangle/arrow icon on any of the devices inside the Combinator


It’s also a good idea to keep the mixer unfolded to quickly allow each layer’s level or pan adjustments and… we’re done!

Method 2: Layering already existing rack devices

Suppose you want to layer these 3 sounds (i.e. Instrument patches):


You may notice that we have a simple instrument (kHs ONE), an instrument (RadKey) with an insert effect (Echobode) and a Combinator based instrument.

The first thing to know about this last one is that you’ll lose the configurations that usually allows you to tweak its internals through the macro-like Combinator rotaries and buttons (more on this on a future tutorial) so make sure Combinator-based sounds are tweaked to your liking before “freezing” them into a new Combinator.

1) So, let’s start by creating a mixer anywhere you want although doing it on a spare rack column will make this less messy.


Now, I’m going to use a trick made possible by Reason 7.1 that will considerably speed this part of the process

2) Shift+Drag (i.e. click-and-drag while pressing the [Shift] key) one of the instruments and drop it below the mixer you created.


This little Shift+Dragging trick will automatically disconnect that instrument from its Mix Channel device and reconnect it to the Mixer device, saving you the trouble to manually doing those extra steps (necessary if you’re not on Reason 7.1):


3) After doing the same to the other instrument…


…you’ll need to be careful with the 3rd instrument, because it’s accompanied by an insert effect, so you need to…

4) Select both devices, the Radical Keys and the Echobode, simply by clicking the instrument and Shift+Click the “last” effect in its audio path to get all selected (there’s only 1 in this example)


5) Now you can Shift+Drag that group of devices and drop them below the Mixer


…and we’re done in regards with unifying the audio paths of those 3 instruments into a unique Mix Channel device.

Now let’s deal with putting this heterogenous selection of devices into a Combinator so all receive the same MIDI notes and performance data.

So, because there’s a Combinator in there (we could have several, the steps are the same) we can’t simply select all those devices and do a Combine action because you’ll get an unexpected messy result, audio-path-wise.

To avoid this, you’ll have to Uncombine, before doing the final Combine.

Something that you may also want, when dealing with many devices, is to collapse them all to see more of them, so simply [ALT]/[Option]+Click the little triangle icon on the top left of one of these devices, this will collapse all the devices on this rack column (this is where using a rack column for this operation comes handy):


Ok, now it’s easier to select them all:

6) Click the Mixer to select it and [Shift]+Click the last instrument or device that belongs to this group that’s going into a Combinator

7) Right-Click on any of the selected and choose Uncombine


This will “explode” the number of devices you’re seeing in the rack because you just exposed all previously hidden devices inside any of the Combinators in this group. Don’t worry, it may look a bit ugly and messy but that’s a temporary price to pay when trying to fit already combined instruments into a new Combinator.

Ok, now we can do the final step: Select them all again, including the newly visible devices.

8) Click the Mixer again, at the top and [Shift]+Click the last device in the group (again, this is where using a new rack column for this procedure pays off, because all the devices you see in that rack column belong to the group you’re working with)

9) Right-Click any of the selected devices and choose the Combine option


…and we’re done!


Playing this Combinator will get you the original 3 sounds being played simultaneously by the same controller or sequencer track, achieving the sound layering we wanted with this example.


But, but, but… !!!

Yes, I know, we answered one question only to get a bunch more questions popping-up:

What about splitting those instruments into different sections of the keyboard?

Isn’t there some optimizations we could do in that audio path and effects in use?

What about those rotary knobs and buttons that now do nothing?

There’s a lot more to say about the Combinator, obviously. This was an light introduction to one of its simplest uses.

Future tutorials will pick where this one left off and introduce more advanced notions and uses of the Combinator that may be helpful to new Reason users trying to grasp what they got themselves into: The wonderful and powerful world of the Reason virtual rack.



Now I have a question for you: Would you do it differently? How and why?

The following two tabs change content below.
Profile photo of Koshdukai
Musically inclined I.T. professional, technically minded Reason user since 2009, with infrequent acts of Sound Designing released in the wild, some captured in Propellerhead Record 1.5, Reason Essentials and Reason 6 Factory Sound Banks as well as in a few Rack Extension factory patch banks. Propellerhead Remote technology coder and enthusiast, having contributed to extending the existing factory Reason maps to new rack devices since 2010.