The Yamaha AN1x Synthesizer mailing list

No worries, Chris,

You wrote:
"...i've never been too sure how to use the LFO on the AN1X--could you give
us a little detail about this approach to the swirl effect?"

Let's see, I'll try...

- The LFO (Low Frequency Oscillator) is, in the analogue sense, a
continuously rising and falling voltage that forms the shape of the waveform
outlined by the LFO Wave type (Knob#5). The Speed of LFO is controlled via
Knob#6, while the Delay (time taken after pressing a note before the LFO
starts) is controlled by Knob#7. For starters, keep the LFO Delay set to
zero so that it's always going when you hit a key.

- Unlike the regular waveform oscillators, the LFO doesn't produce a sound
on its own, rather the rising/falling value can be used to control other
aspects of the synth. Examples include, the Filter Cutoff, the Pitch, or the
'width' of the Pulse Width Modulation (PWM) oscillator.

- To set which parameter you wish to control or modulate via the LFO, and by
how much, you need to increase the Depth.

eg.

- Filter: Fmod Depth (Knob#7)
- Pitch: Pmod Depth (Knob#8, and may be set independently for each
oscillator) 
- PWM: PWM Depth (Knob#6, and may be set independently for each oscillator)

N.B. With a positive value (ie. turning the depth knob clockwise from zero),
the controller moves in harmony with the LFO, whereas a negative value will
result in the controller moving in opposite directions (eg. as the LFO
voltage increases, the filter cutoff decreases).

Regarding the swirl effect, well I'm not sure exactly what's trying to be
achieved, but applying the LFO (depth) to the filter and/or pitch, and
playing with the LFO Speed, you can produce, amongst other things, an alien
helicopter effect... kinda like:

w.w.w.wp.wp.whp.whop..whop...whoop....whoooop......whoooooooop........whoooo
oooooop.......whoooooooooooooooooooop!!!!

If you get what I mean?!! ;-)

Hope that helps.

Phil