HI Folks, ive always loved sounds that use (what I can only describe as) that helicopter type effect like the one used in Planet Earth by Duran Duran, does anyone know what the process if for creating that, im happy the phasing/flanging etc that usually accompanies this effect but its that stuttering or sliced up effect that i am missing? Much appreciate folks and have a great weekend.
 
Jim

Filter swept LFO
Very common sound-effect in the 70s

Gentlman Jim, thanks for the info will have a play around with that over the weekend.

Any decent synth vsti would be capable of this.
 
Jim describes it well already, but I would add "noise" as a part of the sound as well. On a synth, the LFO, filter and noise can be used to create thunder, rain, jet engine, light breeze, helicopter, etc.... etc...
 
EDIT TO ADD: I just listened to the opening of the song.... scratch the noise suggestion. If you were looking to do a more realistic helicopter you would add some noise to it.

Without having tried to to recreate it I'd start with a pretty narrow pulse wave from a VCO which is then passed through a filter that's being frequency swept by an LFO and possibly adjusted by hand as well. After which it heads for the VCA which is also being swept by a square-wave LFO to create the tremolo chopping.

Another technique is no VCO wave at all, just a resonating filter which is heavily swept by a pretty fast LFO saw or square wave to create the chopping, a slower LFO sine or triangle to create a little in-time pitch movement then turning the filter knobs as required. Very easy on an analogue synth, even a Korg Monotron can do this sort of thing very well.

Basically it's a similar idea to how Pete Townshend created the filtered and tremelo on the organ at the opening of "Won't Get Fooled Again" by passing sustained organ chords through a VMS synth's modulated filter and VCA.