Okay, since we’re meanwhile able to layer samples with the native Renoise instruments, it’s possible to achieve a unison FX like the Unsion device in Reason or for example the really phatt unison mode in Sylenth1 does. The most important thing is just to know, what actually is a unison FX and what does a unison device do?
A unsion sounds pretty much like a chorus. Though there are a few important differences. A common chorus modulates its source (pitch & pan) and then provides the result as a second signal, containing the 100% wet signal. Afterwards both signals are mixed (dry/wet), maybe with an additional delay and some filtering for the wet signal. That’s it. The most important difference to a unison is: a unison FX does no modulation. Never and nowhere. All it does is static detuning several clones of the source signal, with some similar work on the panning.
Well, that’s all we’ve got to do. I’m not gonna talk about unison for stereo samples here. Our unison FX is gonna work best and allowing most control with a mono sample. And it’s gonna result in a really phatt and wide stereo signal.I personally prefer using small cycle loops for my instruments. But that’s totally up to you. Use any (mono) sample you like. But remember, we are going to detune the samples. That means, if you’re gonna use a very long and non-looped sample, the end of it might sound pretty messed up. Anyway, here we go:
Step 1: Load your fav sample
Step 2: Set the sample volume
[indent]If you want to achieve a Unison8, you’re gonna need 8 samples, which will be layered. This of course results in a multiplied volume output. So we better take care of this.
A doubled sample with max volume means about +6dB higher volume output on the affected channel. Because we’re gonna pan the layers to max stereo (2 channels), we calculate:
(numberOfSignals - 2) / numberOfChannels * addedVolumeAmount = volumeAmountToReduce
For the Unison8 this means: (8 - 2) / 2 * 6 = 18
So we have to lower the volume in the sample settings to -18dB
The calculation actually isn’t right this way, because we’re not adding max volume samples to each other anymore, but keeping it this way we also get some headroom to play chords/multiple notes at a time.
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Step 3: Now duplicate (right-click -> duplicate) the sample one time
Step 4: Set PAN to full left for the first and full right for the second sample
Setp 5: Now duplicate both again, as often as you need to (For our Unison8 example -> 3 more left and 3 more right panned clones)
Step 6: Set detuning for each sample
[indent]Welcome to the part that depends on you. The “secret” of propper detuning for unison is, to know the maximum amount you want to detune. Yet this part really sucks in Renoise, because we can’t try to adjust and play around with a slider or knob, that affects all related samples. I personally ATM use my Sylenth1 as a reference for this. On maxed out detuning (10.0) we’re talking about 100 cent pitch amount on Sylenth1. That’s one half tone up and down. To phatten up a sound by detuning, without really sounding “off”, usually amounts below 50% of a halftone should be okay. In Renoise the detuning is called “finetuning”, whith a range from -127 (1 halftone down) to 127 (1 halftone up). So, keeping our 50% detuning in mind, normally amounts below 64 (-64 to +64) should work. You really have to try this out. Once you’ve found your maximum detuning, you have to calculate again:
maximumDetune / numberOfSignals * 2 = detuneStepSize
Lets say, for our Unison8 we chose a detune amount of 48. The calculation then would be: 48 / 8 * 2 = 12
Now let’s set the finetuning per sample. Step size is 12.
[indent]PANned full LEFT
sample 00: finetuning: -12
sample 01: finetuning: -24
sample 02: finetuning: -36
sample 03: finetuning: -48
PANned full RIGHT
sample 04: finetuning: +12
sample 05: finetuning: +24
sample 06: finetuning: +36
sample 07: finetuning: +48[/indent]
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Setp 7: Switch to the keyzone editor and drag and drop all samples to it, set the key range for each sample and keep in mind to set the right root key
Well, what you’ve got now is a 100% wet unison signal. Adding a center panned sample without any finetuning would allow you to adjust dry/wet now. Just remember the volume problem then and drop the “-2” in the volume calculation.
That’s pretty much it. May look complicated on the first view, but really isn’t. The only thing that’s hard to find, is the right amount to detune. Setting up an instrument with native unison FX normally shouldn’t take you more than a few minutes. 
). I was hoping some LUA-coder might pick the idea up to write some tool. Really looking forward to this.