Ideally if the low- and high-pass inputs are set to the same amount they should complement each other and the cutoff frequency (and feedback resonance) should have no effect on the sound. One can also connect the same signal to all of the inputs and use the input controls to shape the curve of the filter. This arrangement makes it possible to use the filter as a kind of mixer and spectrally cross-fade between the (independent) input signals.
Here’s a take on Rob Hordijk’s 24dB Filter – the last in my series of Audulus versions of his modules.Īs usual Hordijk gives his own take on the classic Moog 4-pole ladder filter, creating a multimode filter through the addition of high-pass and band-pass inputs all mixed to a single output (rather than a single input with multiple outputs). I’ve posted a simple demo on the Audulus forum, as well as a basic version without the node processors. In my version VCAs 1 & 2 have controls to adjust the amount of modulation applied via the modulation input, and 3 & 4 have controls to adjust the offset, which also makes them useful for scaling unipolar modulation signals.Īs Hordijk points out a matrix can be useful not only for mixing signals, but also distributing them (multiples), as well as creating complex (multiple) feedback loops. (One trick that I’ve found useful to check on which connections have been made, is to zoom out slightly so that one shifts out of connection mode on iOS.)įollowing Hordijk’s example, I’ve included 4 bipolar VCAs (using Audio Attenuator) for the ‘node processing’ – bipolar for the ring modulation and echo-like effects that they make possible, as with the Dual Fader. This means that one has to resort to manually making both parts of the connection, which is not quite as elegant as a single stereo cable and can easily get visually messy and confusing, even though it does open up even more possibilities for routings. it isn’t possible to use a single cable for both a send and a return.
I’ve been experimenting with how to set up something similar in Audulus: Stereo cables, the key element, are possible in Audulus, but unfortunately only in a single direction, i.e. Concerning the size of the matrix itself (and the balance between flexibility and usability) he finds that a 6 x 4 grid is well suited to a typical 12 module (4 panel) Hordijk system since connections can also be made directly without necessarily having to go through the matrix. Hordijk includes two level knobs as well as some ‘node processors’ alongside the matrix ready to be patched in for this purpose, but external sources can but used just as well. This means that instead of a simple on/off connection, a level control or other kind of (more complicated) effect/processing can be applied to each node. Hordijk’s innovation is to use the well established technique of using a stereo cable to provide an insert point, here applied to each node in the matrix. Inspired (like much else with Hordijk) by the EMS Synthi/Putney he gives his own take on the use of a matrix within a modern context. I thought I’d gotten through all the Hordijk Modules, but of course there’s always one more thing…