Sidechain & Ducking

Compressor sidechain with an EQ'd key

The standard. The victim track gets a Compressor whose sidechain input listens to the kick; the built-in sidechain EQ shapes what the detector hears so that only the kick's fundamental triggers the duck.

1. Drop Compressor on the bass. Open the sidechain section (the triangle on the left). Enable Sidechain, choose the kick track; use Pre FX tap so your kick's own compressor or saturator doesn't change the key.
2. Enable the sidechain EQ, set it to low-pass around 120–180 Hz. Now the hat bleed and the kick's click don't trigger the duck — only the thump does.
3. Threshold until the gain-reduction meter shows 6–12 dB on each kick. Ratio 4:1 to 10:1. Attack 0.5–3 ms, release 80–200 ms. Knee 0 for a mechanical pump, 6–12 dB for a softer one.
4. Use the Listen (headphone) button to audition the key signal. If you can hear hats, the EQ is too open.

Glue Compressor sidechain for a soft, musical pump

Glue's SSL-style feedback topology has a slower, rounder gain curve than Compressor. Use it when you want the bass to breathe rather than drop out — deep house, dub techno, lo-fi.

Gate sidechain: the opposite duck (keying a pad with a rhythm)

Gate with sidechain lets the key open the victim instead of closing it. Feed a sustained pad through a Gate keyed from a hat or a MIDI-triggered click track and you get the classic trance gate; invert the behaviour with Flip to get ducking with a hard, rectangular shape.

1. Make a MIDI track with Impulse or Drum Rack playing a 16th-note pattern; set its output to Sends Only so it's silent.
2. On the pad: Gate, sidechain from that track. Threshold so every click opens the gate. Floor −inf for full chop, −20 dB for a softer gate.
3. Attack 0.1–1 ms, Hold 10–50 ms, Release 30–150 ms. Return (hysteresis) 2–6 dB to avoid chatter on sustained keys.
4. Flip on turns it into a ducker: the pad is open except when the key hits.

Auto Filter 12.2 sidechain / envelope follower ducking

The 12.2 Auto Filter has an envelope follower that can listen to an external sidechain. Instead of ducking level, you duck brightness: each kick momentarily closes the bass's low-pass, which takes the harmonics out of the kick's way while leaving the sub nearly untouched. The result sounds like movement rather than volume pumping.

1. Auto Filter on the bass. Filter low-pass, cutoff 300–600 Hz, resonance low.
2. Envelope section: turn the amount negative so the follower closes the filter. Enable sidechain, pick the kick, enable the sidechain EQ with a low-pass if you only want the kick body as key.
3. Attack 1–5 ms, release 100–250 ms. Start with −30% and go deeper until the kick's 100–300 Hz region feels uncluttered.
4. Invert the idea for hats: positive amount, sidechain from the kick, high-pass filter — the hats open up right after each kick.

Roar external sidechain (12.2): ducking the drive, not the level

Roar's modulation matrix has an Envelope Follower, and since 12.2 that follower can listen to an external sidechain. Map it to the Amount of a saturation stage, to a filter frequency, or to Feedback. The kick then controls how distorted or how resonant the bass is, which is a far more interesting pump than a volume drop.

Echo Duck: delays that get out of the way of the dry signal

Echo's Duck (in the Character section, next to Gate) lowers the delay return while the input is loud and lets the tails swell back when the source stops. It's internal sidechaining: the input keys the feedback path. This is how you get vocal and chord delays that are huge but never blur the dry phrase.

LFO / Shaper "fake sidechain": grid-locked curves

No kick needed. Shaper draws an arbitrary curve synced to the beat, mapped to Utility Gain. The duck is identical every bar, continues in breakdowns, and the shape is anything you can draw: a sharp dip with a slow log recovery, a double-dip for off-beat kicks, a triplet shape.

1. Add Shaper (Max Audio Effect) before a Utility on the bass. Set Rate to 1/4 in sync mode. Map its output to Utility Gain; set the mapping range Min to −18 dB and Max to 0 dB.
2. Draw the curve: value 0 at step 0, ramp to full over the first 20–40% of the cycle with a concave (fast then slow) shape. Use the curve handles to bend the segment.
3. Enable Smooth on Shaper (a few ms) so the dip has no step at the start.
4. For a more analogue feel use LFO (M4L) with the Saw Down shape plus some Jitter, or with Depth automated per section.

Envelope Follower to rack macros: multi-parameter ducking

Envelope Follower on the kick track outputs a control signal you can map to any parameter in the set, including rack macros on other tracks. One kick, several reactions: bass gain down, pad low-pass down, reverb send down, hat high-pass up.

1. Envelope Follower on the kick track (it passes audio through unchanged). Rise 1 ms, Fall 100–250 ms, Gain so the meter peaks near full.
2. Press Map, click a macro on the bass's Audio Effect Rack. Set the mapping range inverted (Max below Min) so louder kick = lower macro.
3. Inside the bass rack the macro drives Utility Gain, EQ Eight band gains, Saturator Drive — whatever should flinch when the kick hits.
4. Add a second map to the pad rack and a third to the return's Hybrid Reverb dry/wet.

Utility gain automation and clip envelopes

The most boring and most precise method: draw the duck as automation on Utility Gain (or clip Gain for audio clips). Zero latency, total control per hit, works in a breakdown or not as you choose. Tedious for a whole track, perfect for a drop or for surgical fixes.

1. Draw one beat of automation: −12 to −18 dB at the kick, ramp back to 0 dB over 100–200 ms with a curved segment (Alt-drag the line).
2. Copy-paste the beat for the section. Delete dips where there's no kick.
3. For audio clips, use the clip envelope on Gain instead — it follows the clip when you move it.

Ghost-kick triggers: consistent pump without the kick

A muted trigger track provides the key so the duck keeps going when the real kick drops out, or so that it follows a different rhythm. The key sound is designed for the detector, not for ears: a short sine burst with a sharp attack.

1. New MIDI track, Operator with a sine, pitch env +12 st decaying over 20 ms, amp decay 80 ms. Or any short kick sample.
2. Track output: Sends Only. Every sidechain compressor keys from this track, Post Mixer (so you can automate the ghost's volume to fade the pump in and out).
3. Write the ghost pattern as you want the pump, not as the kick plays. Four-on-the-floor during a breakdown is the classic.

Multiband sidechain with Multiband Dynamics

Multiband Dynamics takes an external sidechain and applies it per band. Duck only the low band of a bass or a whole mix bus, leave the mids and highs alone. This is the cleanest way to sidechain a full-range synth, a pad, or a drum loop with a baked-in kick.

1. Multiband Dynamics on the victim. Set the low/mid crossover around 120–200 Hz, mid/high around 2.5 kHz.
2. Open the sidechain, select the kick, Pre FX. Enable the sidechain EQ low-pass if the kick has a lot of click.
3. Low band: lower the Above threshold until it sits under the kick level; set the Above ratio to a downward value (drag the ratio to the right, display shows e.g. 1 : 4). Attack 1 ms, Release 100–200 ms (global).
4. Mid and High bands: ratio 1:1 (or bypass with the band's solo/off buttons) unless you want a mild full-band duck too.
5. Experiment with ducking the mid band less (ratio 1:1.5) so the pad keeps its presence while the lows breathe.

Sidechain across hardware: CV Tools and the TD-3

If the bass comes from the TD-3 or the modular, duck it inside Live after the External Instrument / audio input exactly as above. If you want the duck to happen in the rack, send a CV envelope from Live: CV Envelope Follower on the kick track outputs a DC-coupled control voltage via a DC-coupled interface output, into the VCA's CV input, inverted. Or use CV Triggers to fire the modular's own envelope generator on each kick and patch that into the VCA.