How-to: Create Additive Synth Sweeps in Ableton

Can't modulate partials? Record it live to create evolving synth tones
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Ableton’s Operator is incredibly powerful when it comes to FM and basic additive/subtractive techniques, but like several other additive softsynths, there’s no way to animate the harmonics for morphing effects. Fortunately, there’s a workaround that lets users create their own smoothly morphing harmonic structures. It just requires a few extra steps, but the result is shimmering, animated textures that are well-suited for unique pads and leads.

STEP 1

Fig. 1a

Fig. 1a

Fig. 1b

Fig. 1b

Begin by creating a MIDI track with Operator (or another additive synth) as its instrument. Start with the factory default patch and experiment with various mouse, finger, or trackpad gestures to hear the results of different sweep techniques. [Figure 1a or 1b]

STEP 2

Fig. 2

Fig. 2

Most basic samplers, including Ableton Simpler, use middle C as the root key for key assignments. For newcomers, the ‘root key’ is the note at which the sample plays back at its original pitch. So, in order to create a sweep that will import directly into Simpler, create a sequence clip that contains a sustained middle C. Eight measures at 100bpm should be adequate for everything except extended legato pads—and of course, looping the sample is also an option. This sequence will sustain the note while you use your cursor to manipulate the harmonics. [Figure 2]

Fig. 3

Fig. 3

STEP 3

With the sequence in place and a bit of rehearsal for your sweep, route the output of the Operator track directly to the input of an audio track in Ableton [Figure 3]. This will let you quickly record multiple takes of your sweeps until you capture one that inspires you. Labeling your tracks in all caps with obvious titles like “Source” and “Record” will speed things up by making their names easy to find as you use the menu pull-downs for routing. From there, record a few sweeps.

STEP 4

Once you’ve animated your harmonics and recorded the result, create an additional track containing Simpler (or an equivalent sampler in your DAW of choice) and drag the recorded audio clip directly into its sample area [Figure 4]. Now your recorded harmonic motion will be played as a sample. Note that Simpler also lets you warp this swept motion, so any rhythmic or cyclical changes can be retained across the keyboard. Each Warp mode has its own strengths (Beats is excellent for simple rhythmic material) so experiment with the various options until you find a mode that suits your audio.

Fig. 4

Fig. 4

From there on out, you can go ahead and use Simpler’s synthesis tools—like filtering, envelopes, and LFO—in order to further sculpt the sound before adding effects. If you’re creating a pad texture, you could consider applying chorus and reverb to the sound, and then grouping the final configuration into an Instrument Rack before saving it to your user library for future use.