Adding up

Computer Music - - Make Music Now / Spectral Synthesis -

Ever played with an ad­di­tive syn­the­siser that can resyn­the­sise an au­dio file? If so, all this may seem quite fa­mil­iar. In­deed, at their core, ad­di­tive resyn­the­sis­ers work in much the same way as ded­i­cated spec­tral synths. Both em­ploy FFT to ex­am­ine an ex­ist­ing sound, al­low­ing ac­cess to smaller har­mon­ics or groups of har­mon­ics.

Note that while ad­di­tive syn­the­sis can be viewed as a form of spec­tral syn­the­sis, it can dif­fer in that an ad­di­tive resyn­the­sis isn’t merely ac­cen­tu­at­ing or at­ten­u­at­ing ex­ist­ing har­mon­ics, but ac­tu­ally analysing a sound and re­build­ing it as a col­lec­tion of in­di­vid­ual sine waves. Each of those sine waves needs its own os­cil­la­tor, and more os­cil­la­tors mean a more de­tailed rep­re­sen­ta­tion of the sound be­ing (re) syn­the­sised. Early ad­di­tive synths of­fered a lim­ited num­ber of os­cil­la­tors and less re­al­is­tic recre­ations of a given sound. Hap­pily, with mod­ern com­put­ers, such lim­i­ta­tions are mostly used for the sake of user-friend­li­ness.

Tra­di­tion­ally, ad­di­tive synths present the har­monic con­tent in play as a col­lec­tion of ver­ti­cal bars or slid­ers that rep­re­sent the static state of each par­tial’s am­pli­tude, while fa­mil­iar en­velopes are pro­vided to con­trol that am­pli­tude (and other things) over time. While these meth­ods of­fer de­tailed con­trol, they can be te­dious to use. The pay­off comes in the abil­ity to do more than sim­ply al­ter an ex­ist­ing sound, but to thor­oughly trans­form that sound into any other sound, one par­tial at a time.

A pri­mary dis­tinc­tion be­tween a spec­tral synth like iZo­tope’s Iris 2 and an ad­di­tive synth such as VirSyn’s Cube is that the lat­ter can be used to build sounds from scratch us­ing in­di­vid­ual sine waves, rather than re­ly­ing on im­ported or an­a­lysed con­tent.

Some ad­di­tive synths – like Ap­ple’s Alchemy – blur the line by of­fer­ing spec­tral ed­i­tors along­side more tra­di­tional ad­di­tive ed­i­tors.

Edit­ing a spec­tral image is quite sim­i­lar to edit­ing a resyn­the­sised sound in an ad­di­tive syn­the­siser

Newspapers in English

Newspapers from Australia

© PressReader. All rights reserved.