Hey! I was trying the past day to mimic the specific feature of “oriental” keyboards which allows you to lower certain notes in every octave by a quarter tone, thus enabling usage of Arabic/Iranian/Indian scales. To my surprise, Renoise comes with a crazy meta instrument called Formula so I could scribble some Lua and get it done!
Here’s a screenshot because I feel like nothing is real if it doesn’t have an image attached:
The value at “note 1” means that D will be lowered by 1/4 tone in all octaves (and the value at “note 2” means no additional change), letting us play on Maqam Bayat (intervals: ¾ ¾ 1 1 ½ 1 1). How the hell does that mean D? Well, I couldn’t find a nice way for you to specify note information, so the next best thing I came up with is the following weird numeric representation of notes on the 0..1 range provided by the macros:
0.01 => C
0.02 => C#
0.03 => D
0.04 => D#
0.05 => E
0.06 => F
0.07 => F#
0.08 => G
0.09 => G#
0.10 => A
0.11 => A#
0.12 => B
In order for an instrument to be controllable by this doofer, it’ll have to have a macro controlling a pitch modulation, preferably an operand but idk do whatever you want!
This is how it sounds like, and this is the modulation macro required for it to function:
(I love that the sound came out completely shat upon. sorry first time OBS here)
Due to Formula’s limited parameter amount, we can only apply this to two notes at a time. This shouldn’t be a problem at all because I haven’t seen a Maqam that requires more than two (most require just one).
Moving forward, I wanna automate somehow the process of adding the pitch modulation, which feels a bit like a hack of itself, which I resorted to merely because I couldn’t find a way to finetune an instrument on the fly via a normal effect.
Anyway, hope you like it 
Quarters.xrdp (9.5 KB)