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Reason Tips & Techniques By Robin Bigwood
Published May 2012

Explore the potential of complex sound layering with Reason's Combinator.

1: Combinators let you easily create layered timbres, instantly broadening the scope for sound design.1: Combinators let you easily create layered timbres, instantly broadening the scope for sound design.

Reason's synths and samplers are extraordinarily flexible and powerful, but there's a limit to what any one of them can achieve. Start layering them, though, and all sorts of possibilities suddenly open up. Colossally complex pads, snarling 12-oscillator monosynths, acoustic/synthetic hybrids, mighty orchestral textures... They're all possible when you utilise the Combinator to play multiple devices at once. Somehow, layering seems to add instant sophistication and depth to arrangements, and if you just need great results in the minimum of time it'll let you create genuinely unique sounds just by combining presets. If you haven't tried it, it's a whole new approach to sound design.

Quick Layers

Combinators are created just like any other device in Reason. You can right-click an empty part of the rack and choose Other > Combinator from the contextual menu that appears. Or make sure nothing is selected in the rack and do the same from the main Create menu. In Reason 6, they're created ready-patched to a Mix Device.

So how would we use this to layer a couple of instruments? The first step is to give your Combinator its own mixer. We'll see why this is so crucial in a moment. Right-click in the currently empty 'Devices' area (which will be confirmed with a red 'insertion line') and choose Other > Line Mixer 6:2. Then, right-click again just beneath the new line mixer, and create an instrument of your choice, then repeat the process to add another one. In screen 1, I chose to create a Malström and a Subtractor.

Now, as long as your Combinator is record-enabled, playing your MIDI controller will result in both these instrument devices playing. That's it: a basic layered sound.

Ins & Outs

Let's just pause for a minute and look at some of the subtleties of what just happened. You can play two synths at once here because a Combinator passes on MIDI information to all the devices it encloses. And, of course, that's as true for two synths as it is for 10, or 20 or more...

You'll notice, too, that your synths did not get their own Mix devices, mixer channels, or sequencer tracks. That's because a Combinator is essentially a dedicated grouping device that lets you build device combos that act as self-contained units, and which don't clog up your song with redundant 'infrastructure'.

As for audio handling, a Combinator has only one stereo in and out. That's why you'll always need a submixer for layering two or more instrument devices. The instruments feed the submixer, and the submixer feeds the Combinator's output. The Line Mixer 6:2 device will frequently be perfect for simple duties, but don't rule out the bigger Mixer 14:2, which has handy channel EQ and more effects patching facilities.

Going On

2: A simple MIDI routing, linking Combinator's first rotary knob with Thor's Filter 1 Frequency parameter. I've renamed the knob 'Metallic', as that's the quality it ends up controlling in this specific layer of patches.2: A simple MIDI routing, linking Combinator's first rotary knob with Thor's Filter 1 Frequency parameter. I've renamed the knob 'Metallic', as that's the quality it ends up controlling in this specific layer of patches.

So what more is possible with a simple setup like the one we just created? Firstly, and most obviously, you can use the Line Mixer 6:2 to balance the relative levels of the synths, and pan them too. Panning pairs of quite similar layered sounds (such as pads) hard left and right can really open out the stereo image.

You can also add effects to your instruments. For individual 'insert' style effects that act on just one instrument at a time, right‑click the instrument and choose 'Effects >', then the effect you want. Reason is smart enough to patch the effect device between the instrument and submixer. To share an effect (like a reverb) amongst all the instruments in a Combinator, right‑click its submixer, and choose 'Effects >' as before, to automatically patch the new device into the submixer's Aux send/return loop. The Line Mixer 6:2 has just one of these — all you need for that touch of reverb — but the Mixer 14:2 has four, for more complex needs. Then simply raise the corresponding aux-send level on each mixer channel to add in the effect.

Finally, when you've finished tweaking your layered Combinator, you can click the Show Devices button to 'collapse' the vertical height, and make your rack more manageable. Just click it again when you need to tweak once more.

Program Music

While a Combinator's basic functionality is quite easily understood, it has a more complex and interesting side, which you reveal by clicking the Show Programmer button. The Programmer is best thought of as a sort of intermediate layer between incoming MIDI data and the devices, which gets round an unforeseen problem, and does some other cool things.

That problem? It's to do with the way Combinator distributes incoming MIDI messages to all its devices. Imagine you had a Thor and Malström within a Combinator, and you wanted to use a hardware control surface to tweak Thor's Filter 1 cutoff. If the Combinator indiscriminately passed the data (MIDI CC 74) on to both synths, Thor would respond as you wanted, but Malström's Filter B frequency would also get involved, as that parameter is hard-wired to the same MIDI CC number.

Clearly, that situation is unworkable, so in fact Combinators filter out all MIDI controller data except for what are termed Performance Controllers: Pitch Bend, Mod Wheel (CC 1), Breath Control (CC 2), Expression (CC 11), Sustain Pedal (CC 64) and Aftertouch. So if you do want to tweak the parameters on a 'combined' device, you have to do it a different way: you link a specific parameter with one of the Combinator's 'virtual rotaries'. Then you tweak the virtual rotary. Far from being a hassle, this approach is quick to work with, and actually has unique benefits, as we'll see.

Going back to the example I just gave, here's what you'd do.

1. In the Programmer, click Thor in the device list on the left. This brings up its 'modulation routing' in the display on the right, and you'll probably find Rotary 1 already listed in the source column.

2. In Rotary 1's row, click in the Target column. Virtually all Thor's parameters pop up, sub-grouped by section and type. Choose Filter > Filter 1 Freq.

That's all there is to it. Now clicking and dragging Rotary 1 with the mouse will control Thor's Filter 1 Frequency. If you want to tweak it from your hardware controller, it responds to MIDI controller 71. The 'Rotary Mappings' box shows the real-time controller mappings for all four rotaries. You can also give rotaries more descriptive names. Simply double-click their labels and type away, before hitting Return.

Multiple Routing

3: You can link a rotary knob to multiple parameters — in this case the Index on both oscillators of a Malström.3: You can link a rotary knob to multiple parameters — in this case the Index on both oscillators of a Malström.

Combinator controller routing is easy to set up, as we've seen — and, what's more, you're not restricted to one routing at a time. For example, at the same time as Thor responds to the Filter 1 routing I just set up, I could get Malström's Oscillator Index parameters hooked up too. Tweaking the rotary would result in all three parameters changing simultaneously.

Here's how I'd do it. In the programmer, I'd click my Malström in the Device list. Then, in the Routing section, I'd configure two rows to have Rotary 1 as their source. The first gets a target of Osc > Oscillator A Index, and the second Osc > Oscillator B Index.

That's a quite complex and potentially exciting-sounding controller mapping already, but the exact behaviour can be further refined thanks to the Min and Max columns. These default to values of 0 and 127 respectively, and those numbers relate to the adjustment limits of the parameter being controlled.

So let's say I want Rotary 1 not to sweep through the whole Oscillator Index range on Malström, only a bit of it. I'd go into the routing configuration again, and change Oscillator A Index's Min value to 40 and Max to 95 (for example). Now the Rotary still sweeps the whole range of Thor's Filter 1 Cutoff (0 to 127), but a more restricted range of the Malström Index. And here's the really cool bit. If I find the Oscillator B Index routing and set the Min value higher than the Max, I'll have inverted the control relationship. So, as I tweak, the Rotary Oscillator A's Index will sweep in one direction, while Oscillator B's will go in the other.

The more you explore the programmer and experiment with routing like this, the more you realise its scope. It begins to act like a 'master' modulation matrix for all the devices contained in the Combinator, and it can hook into parameters that aren't otherwise controllable in real time. Next month we'll take this further and look at some more specific examples of interesting routing setups.  

Rotary Mappings

Here are the MIDI controller numbers a Combinator's rotaries respond to:

RotaryMIDI CC Number

Many MIDI keyboard controllers will have presets featuring these common sound-oriented controllers ready-rolled.

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