Droner — a four-voice drone synth inspired by four-track tape recorders

As well as oscillator bank-style drones, like the Tangible Waves’ Drone38 and DroneX modules (among others, but those were the ones I was looking at when I decided to try my own take on the concept). But once I had my oscillator banks set up, I was… sort of bored. So I mashed them together with the idea of using a four-track recorder as a type of synth by recording droned chords onto each track, then using the mixer to “play” the synth — out of that, a set of UI faders was conceived and added. Once I had that in place, I wanted some filtering to shape the tone, and I figured distortion/overdrive added more harmonics for filters to chew on (and just sounded nice). A few tape effects — a pitch warble, a tape stop (courtesy of a suggestion by Rob Smith), some crackly corrosion — and Droner was born.

So, no “tape” is present, or even recorded audio — everything comes from banks of sawtooth oscillators — but the effect is, I think, quite similar to that approach to the four-track tape recorder, and it excels at making dense but crumbly textures. (Pair it with some reverb, or delay, like I do in the video.) (You can employ airport loops — and probably some other looper patches, it’s just the one that comes to mind — in a similar fashion, if you want to record some drones into it.)

It’s not a terribly flexible or dynamic sound, but the “faders” do make it very inviting to play, I think, and the core sound has its appeal.

CPU was quite limited, so I didn’t include an audio pass-through. It’s possible there’s enough CPU to support it, but I didn’t want to chance it. The audio is sent to both outputs, but it is a dual mono signal; there is no stereo separation between the channels.



Left — this introduces a momentary “tape stop” effect (in actuality, it just drops the oscillator frequency fifteen octaves). The rate of the “tape stop” is determined by the Slew control.

If you are loading the patch in Zebu, there is a user button already assigned to this function.

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There are four columns of Virtual Faders. If you press a button, the “track”/oscillator bank’s level will change to that position, so, from top to bottom, the buttons represent: 0%, 25%, 50%, 75% and 100% volume. This isn’t the most precise approach to mixing, but it is fast and (I think) fun. (It does cost a fair amount of CPU, though, so if you’d like to use some other method, you could probably save ~15-20% CPU by removing the faders and putting the CPU to other purposes.)

Because the changes to volume are quite large, I wanted to introduce a means of smoothing out the transitions from one condition to another. So the Slew control moderates the speed that changes to the faders take effect. This same slew amount also controls the speed of the tape stop effect.

Next to each fader are controls for the frequencies of the oscillator bank associated with that fader. Each bank contains three sawtooth oscillators. You can tune these to chords, but also tune them each to the same frequency (or detune them from that frequency for thicker sound, or octave intervals of the root, etc.), or tune them to inharmonic clusters, or even use sub-audio frequencies — when all the oscillators are tuned to sub-audio rates the patch produces rhythmic beating (that can be accentuated by the filters and drive), but mixed with audio rate oscillators, these sub-audio elements will (subtly) interfere with the audio rate oscillators.

Along the bottom of the patch, between the faders are controls for the effects. These are added post-mix.

The high-pass filter can be used to sculpt the bottom end. But increase its resonance and it begins to add bass instead of taking it away. In conjunction with the drive, the resonant high-pass filter can really sing and represents another “playable” element of the patch.

Corrosion introduces a digital noise/audio rate modulation of the amplitude. The effect is the introduction of audio drop-outs as well as audio artifacts, like noise and a sort of crinkling sound.

Drive controls the input and output gain of the overdrive module (the germ model) simultaneously. There’s no smooth taper, but generally, as drive is increased, the patch’s volume will increase (not a ton, but some), before leveling off and finally lowering again as the drive amount nears 1.

The low-pass filter is a 12 dB/octave (or two-pole) design, created by running two filters in series. I wanted to be able to “smother” the sound more than the stock one-pole filter allows. It also has a resonance control, which allows for accenuating harmonic content and performing more assertive sweeps of the output.

Finally, there is a warble control. This is a depth or intensity contol of a pseudo-random pitch modulation, meant to evoke the warping of a cassette. At subtle settings, it introduces a nice movement to the sound. At more extreme settings, the pitch swoops around, rising and falling quite a lot.

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