Sound Design: Ring Mod with low-frequency modulations

Audio example of Ring Modulation with low-frequency modulations

Experiments with complex ring modulation and low-frequency modulations for sound design. Each ring modulation generates sidebands for the previous signal and with four ring modulations up to 16 frequencies could be generated. Modulating with ring modulation leads to interesting, synthetic sounds due to the ratios of frequencies changing over time. Having multiple orders of ring modulations allowed for interesting patterns of spectrums to develop (see spectrogram).

Spectrogram from Audacity (2048 bin size, 0-16000 Hz, linear)

This example has two instruments, RM1 and RM2. RM1 uses exponential envelopes to start and end at harmonic ratios but has different rates of change due to different starting ratios. (Mentioned here as ratios since the outputs are being used to multiply the p4 base frequency.) RM2 is a variation on RM1 and uses a sawtooth LFO for one of the modulations. Both use a high-pass filter to remove frequencies generated below the base frequency.

The score plays a pattern with RM1 twice, once with 0.5 durations and again
with 0.25 durations. This sounded to me like they could be used as a simple
laser sound in a game or as a component of more complex laser sound design. The score then has a 20 second long note for RM2 that gives it enough time to hear the evolving frequency patterns.

Sound Design: FM with Modulations

Audio Example of Complex FM sound with modulations to indices

Complex FM (4 operator, what Chowning and Bristow calls Parallel Carrier,
Independent Modulator in “FM Theory and Applications”). The two operator stacks are using 4:2 and 1:1 C:M ratios. expseg envelopes are used to modulate the overall shape of indices and unipolar square lfo’s are used for an additional layer of modulation. I thought the 12 and 3 Hertz for the lfo’s gave some nice texture between the two layers.

I think it probably works best in the low end to middle of the frequency range. The result using pch of 5.00 reminded me of things heard in some progressive house tracks.