The Official Sequential/Oberheim Forum
OTHER DISCUSSIONS => General Synthesis => Off Topic => Topic started by: SuzanneRA on October 20, 2018, 06:20:29 AM
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Hi,
Sorry if this is a really silly question but I am struggling to understand why you would use one LFO rate to control another LFO rate...?
Wouldn't it be easier just to use one LFO at one rate ?
Am I missing something ?
Sorry, but I have been messing with my Prophet 12 LFOs and I just cant get my head around this one.
Thanks.
Suzanne.
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When you’re playing around trying to figure out what speed to run an LFO, sometimes it’s fun to hear a slow pulse that gradually increases to a quick pulsing sound and then maybe grinds up into audio range.
Well, if you’ve ever done that with the speed knob and thought it sounded cool, you can imagine having another LFO Control the speed knob for you.
Imagine a hub cap spinning or a coin spinning in its edge. It’s rotation sound is periodic, but as it gets closer to stopping and it tips over, the rotation speed increases and the pulses get quicker and then more quick. You could simulate that manually, or use an envelope to increase the LFO speed. But if you wanted to hear that same cycle over and over if the rotation speed getting faster as time goes on, you’d use another LFO to control an LFO.
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You cannot use the rate of one LFO to change the rate of another LFO, since the rate value is static and not available as a modulation source...
but for the case of the output of an LFO routed to another LFO's rate parameter, this can be useful for lots of things... a very miniscule modulation amount can give some "randomness" in a vibrato for example, which could be useful if you want the vibrato to not be surgically precise (if you tried simulating a vocal vibrato sound for example).
Other uses are crazy modulations for FX sounds...
I've done this extensively in my ongoing bank, to achieve motion in my sounds in various ways... some even by doing feedback (modulating LFO1 rate/amount by LFO2, which is again modulated by LFO3 and then LFO4 only to modulate LFO4 by LFO1 again, creating some insanely weird inter-modulations).
just experiment :)
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LFOs are typically simple wave shapes. Modulating your LFO (with another LFO or something else) gives you the opportunity to add complexity to your LFO, and give you wave shapes that you wouldn't otherwise be able to achieve.
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Thanks for the replies Everyone, so much to learn....
There are some interesting concepts to grasp.
I haven't even started to look at the extra Envelopes section...It kind of scares me because I just have no idea why I would want them :)
Thanks again.
Suzanne.
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The extra AUX envelope are useful for lots of things... The filter and amp envelopes are self explanatory, but you could route the AUX envelope to any other parameter for added movement in the sound.. Exemples:
Shape parameter... To achieve a one shot envelope on Pulsewidth for example.
Pitch parameter... To create sound where the transients glide into pitch... Lots of real instrument glide into pitch like flutes or even the human voice
Audio Mod parameter... Which will let you introduce movement into filter FM (effective with filter resonance at maximum and filter keytrack at 64 (filter playable on keys in self resonating mode)
There are lots of uses for that envelope, I sometimes wish it had four envelopes total.
Again... Experiment, there are lots of modulation destinations to try it out with besides filter and volume.
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I haven't even started to look at the extra Envelopes section...It kind of scares me because I just have no idea why I would want them.
I’d really like to get a synth which has auxiliary envelopes as I’ve found occasions where I’d like to change another parameter but can’t. For instance you could use one to modulate the pulse width of a square wave independently of the filter envelope. Or you could use one to fade in and out the volume of a second oscillator, a noise source or a second layer. There are so many cool possibilities.