Today I continued on the Harmonics patch. As I said in yesterday’s post, the switching of the mapping between brain harmonics and sound harmonics, still created audible clicks. This is totally to be expected, but still something that had to be dealt with because it just doesn’t sound good in an analog ambient patch. To reiterate, I detect a moment of switching when the maximum value of any of the brain harmonic CVs dips below a certain low threshold, using a comparator with some hysteresis provided by the Disting Mk4 and the Doepfer A-185-2 precision adder to provide the reference voltage. In this way I hoped that during these relatively low volume periods, the clicks would occur less. However, they still remained.
To fix this, I now added a VCA, CV invertor, and an envelope to the mix. I needed the Doepfer A-185-2 precision adder for this, so now generated the reference voltage by a module that Robert made in the early days of the EEGsynth, when we still expected to end up with a hardware module soon. Now it came in very handy (bottom left in the small case, in the video below). The Disting generates gates, so I used the Klavis Logica XT to convert the gate into a trigger to randomly switch to several matrix patches of the SSSR labs Matrixarchate. This time I also spend some more time on programming the mapping so that it sounds a bit better than before. The higher odd harmonics are just a bit unstable on the Verbos Harmonic Oscillator, and in general wider spaced harmonics seem to sound better as well. Now, the new part of the patch is that instead of directly triggering the matrix, I instead trigger an envelope on the Frap tools Falistri. It can create a trigger at End of Rise (EOR), so at the ‘peak’ of an attack-release envelope. I used this EOR trigger to switching of the matrix. At the same time, I invert the envelope with the precision adder, creating a flipped, negative envelope for the Intellijel Quad VCA through which I now route the sound to the mixer. I then only needed to calibrate the amount of positive bias (the larger knob on the VCA), and the amount of CV (the small knob), to suppress the right amount at exactly at the moment of the switch (or rather the logic is the other way around, but you get my point). By adjusting the rise/fall times of the envelope different effects can be created – quick attacks sound as if a key is truck, while slower attack and releases result in more smooth transitions. The latter was the intent for now, and works very well with a lot of reverb, smoothing out and mixing the different harmonics over time.
After running the patch for a while I thought it might be nice to thicken the sound even more, by adding a second oscillator, tuned down relative to the first harmonic, and using wavefolding to add natural higher harmonics to that as well. Enter: the Verbos Complex Oscillator. I still remember the first time I heard it, after having only had a digital wavetable oscillator. It blew me away, and it made my patches sound so rich and deep. It has its own wavefolder, with control over odd/even harmonics, and the symmetry (where on the ‘y-axis’ the waves are folded). A perfect companion in the harmonics patch, especially if it’s not to prominent. I patched the different brain harmonic CVs to the degree of wavefolding (theta), symmetry (alpha) and odd/even control (beta). The output signal was routed through the Quad VCA, as since the CV there is normalized over the inputs, I could have it duck at the same time as the sound coming from the Harmonic Oscillator. I also added a filter after the Complex Oscillator since it is so rich once it starts folding, its good to smooth it out a bit sometimes. However, as I used the crazy Doepfer A-124 Wasp filter, it also combines very well with rich harmonic signals when cranking up the resonance to full, creating some characteristic breaking down over some intervals that just tickles me so. I add a bit of it to the end of the recording. For completeness sake I have to say that I also added a filter (XAOC Devices Belgrad) and phaser (XAOC Kamieniec) after the Harmonic Oscillator to subtly liven up the sounds. I ended up using the filter mainly for it’s input attenuation before going in the phaser, because the latter distorts too quickly (for this patch) with the hot signal coming from the harmonic oscillator.
Now that was quite a bit of text to describe the patch. Let’s have a listen, using again simulated EEG data. I think I’ll be ready soon to make a final recording with live EEG and move on to a next patch. I hope you enjoy it, and thanks for sticking around!