This video, via Steve Hunt, demonstrates using the Yorick Tech Low Frequency Expander (LFE) to add modulation options to the Korg Prologue synthesizer.

The LFE is designed primarily for the Sequential OB-6 and Prophet 6 synthesizers, but it can also control the Korg Prologue, another synth with relatively few modulation sources. The LFE adds 3 complex LFOs and a complex 6-stage envelope generator, which can also be used as a 2 to 16 step sequencer.

The video demonstrates some of the additional modulation possibilities available with the LPE:

1. Runner Brass. Two slow LFOs modulating VCO1 and VCO2 shapes giving a very rich sound, envelope modulating filter resonance so each note starts without resonance, another (fast) LFO modulating filter frequency but only brought in with increasing velocity.

2. June Pad. Chorus speed controlled with envelope so it speeds up through the note then slows down. Reverb off during note but then full depth after note released.

3. In my dream. Velocity and LFE’s envelope modulating Xmod depth, velocity modulating timbre balance reducing the level of the ‘tinkle’ with more velocity. LFO 3 comes in after about 2 seconds with a repeating pattern modulating the filter frequency, then I change the pattern type.

4. Solid Bass. Complex envelope modulating filter freq , LFO1 modulating VCO1 shape to give more richness, LFO2 is a key-triggered saw wave modulating Osc3 shape which gives a dark beat, LFO3 does the same with resonance giving a ching-ching beat with increasing velocity.

5. Opal mine. 7-step sequencer controlling filter frequency, filter freq and res controlled by LFO 2 and 3 giving the flutter effect, velocity controlling the Korg’s LFO rate.

6. ReeseFlux. Envelope controlling the Korg’s LFO rate and the depth of LFO1’s sine wave which is modulating filter drive. LFOs 2 and 3 are modulating resonance and filter freq which come in after a few seconds.

8. Sherbet. Longer sequence modulating filter freq, LFO2 modulating Osc3 shape with velocity, LFO3 modulating filter res.

9. Raid rush. Envelope modulating filter env depth, velocity controlling the Korg’s amp envelope’s Attack time, LFO 2 modulating Osc3 level with a saw wave, LFO3 controlling filter freq.

10. Sparkle. Envelope controlling Osc 3 shape, 3 LFOs coming in after a del and/or fade to modulate filter frequency and VCO1 shape.

11. Poly spread. Complex envelope controlling filter freq and 3 LFOs coming in after delays to modulate 2 VCO shapes and filter env depth, one with just 3 cycles.

14. Cinematica. Envelope controlling Osc3 shape, filter freq controlled by a delayed stepped wave from LFO1, LFO2 modulating resonance, LFO3 brought in by velocity to affect VCO2 Octave giving the repeating beat pattern.

For details on the LPE, see Yorick’s Facebook page.