Reaktor/Tutorials/Reaktor as effects processor/Matrices
Suppose you wanted to link several instruments together in every possible combination of serial and parallel routing, so you could quickly discover all the best combinations. This is easy to do with a mixing matrix, available in various sizes in the R4 Macro library. But hooking these up to get the results just described will take a little tweaking. The most basic way to use a matrix is to send a different source into each input and hook a different destination to each output, so that any source can feed any destination. This is how most modulation matrices work in R4 ensembles.
To make a matrix that sends a single input to all destinations in any order, you need to loop the output columns back into the input rows, taking care that you don't create feedback loops, unless that's what you want.
Here's a stereo, 3x3 mixing matrix made from the same 8x8 mixing matrix shown in the previous example that will give you all possible combinations of three different effects. Notice that a diagonal set of knobs has been muted and hidden to avoid feedback, and that alternate knobs have been muted and hidden within each junction of rows and columns that's needed to create a stereo path, so that each side of the stereo signal is sent to only one side of the output pair, and not equally to both sides.
Here's the finished matrix, with linked and hidden knobs, and a snap set that covers all of the most obvious routings, plus a few less obvious ones that include the output of a single processor, or the dry signal, along with a routed signal. Many more are possible.
An effects ensemble built around such a matrix can be easily played with all panels collapsed and only the matrix snap window visible.
8x8 is the largest prefab mixing matrix in the R4 library, perfect for a 7x7 mono matrix. But it would be easy to create a 7x7 stereo matrix by duplicating the mono version within the same instrument and sending one side of each stereo effect's inputs and outputs to each matrix. Corresponding knobs on each matrix panel could be linked for control by a single knob, and then the linked panel could be hidden. 5x5, 6x6 and even 9x9 matrices would simply require the deletion or addition of one or more of the macros that create the rows and columns within the original 8x8 macro.
The challenge, of course, is to come up with sets of effects that combine well when routed in all possible ways, or even in most of them. I start by looking for effects with very different, obvious, but somewhat transparent textural qualities, such as a filter, a delay, and a gate... or maybe a distortion, flanger, and comb-filter. Dense or subtle effects like reverbs, tremolos, bit crushers, panners and pitch shifters tend not to work so well, but try ‘em all, and don't forget that you can also patch global effects, like reverbs or compressors, after the output of the matrix; powerful (and potentially CPU-intensive!) stuff...