Sidechain Compression: The Pumping Sound of Electronic Music

What Is Sidechain Compression?

Standard compression reduces a signal's volume when it exceeds a threshold. The compressor analyzes the input signal and applies gain reduction based on that same signal.

Sidechain compression separates detection from processing. The compressor reduces one signal's volume based on another signal's level. This creates a relationship between two sounds: when one plays, the other ducks.

In electronic music, sidechain compression typically links the kick drum to the bass or the entire mix. When the kick hits, other elements temporarily reduce in volume, then return. This creates the "pumping" or "breathing" effect characteristic of modern dance music.

Origins in Broadcasting

Sidechain compression originated in radio broadcasting during the 1930s. Engineers needed spoken announcements to be audible over background music. They developed "ducking"—automatically reducing music volume when the announcer spoke.

The DJ's voice triggered a compressor on the music channel. When speech was detected, music level dropped. When speech stopped, music returned. This technique remains standard in radio, podcasts, and PA systems.

Sidechain in Vinyl Mastering

Before electronic dance music adopted sidechaining, vinyl cutting engineers used it to prevent technical problems.

Vinyl records store bass frequencies in the center of the groove. Excessive bass energy causes the cutting stylus to make wide lateral movements, which can cause the stylus to jump out of the groove during playback or reduce playing time.

Engineers sidechained bass to the kick drum, briefly reducing bass energy when the kick hit. This allowed powerful low end while maintaining groove integrity. The technique was practical, not aesthetic—but it created a sound that would later become intentionally desirable.

French House and the Pumping Sound

In the late 1990s, French producers transformed sidechain compression from utility to aesthetic.

Daft Punk's 1997 album Homework made heavy sidechain compression a stylistic choice. On tracks like "Around the World" and "Da Funk," the entire mix pumps in response to the kick drum. Rather than subtle ducking, the effect was exaggerated and rhythmic.

The technique served musical purposes:

Rhythmic volume modulation adds movement beyond what drums alone provide. The music breathes in time with the beat.

French house producers heavily sampled disco and funk records. Sidechaining unified disparate samples, making them feel like a cohesive production rather than collaged parts.

When everything ducks for the kick, the kick seems more powerful. The contrast between kick moments and non-kick moments emphasizes low-end impact.

Eric Prydz's 2004 track "Call on Me" demonstrated commercial sidechain compression, reaching #1 in multiple European countries. The pumping effect was unmistakable and deliberate.

How It Works

Sidechain compression requires three components:

This is the signal that controls compression. In dance music, this is typically the kick drum. Every time the kick plays, it triggers compression on the target signal.

This is the signal being compressed. Common targets include:

• Bass synthesizer
• Pad/chord layers
• Full mix bus
• Reverb returns

A compressor with sidechain input capability. Most modern DAW compressors include this feature.

The release time is critical. It determines how long the ducking lasts and how the signal recovers:

• Too short: Pumping sounds choppy and unnatural
• Too long: Signal doesn't recover before next kick
• Right setting: Smooth, rhythmic breathing synchronized to tempo

LFO Sidechaining

In the 2010s, producers began replacing compressor-based sidechaining with LFO (Low Frequency Oscillator) tools.

Steve Duda, creator of the Serum synthesizer, developed early LFO sidechain plugins. Rather than using a kick drum as trigger, these tools use a tempo-synced volume curve that repeats each beat.

Advantages of LFO sidechaining:

• Consistent: Every duck is identical
• Independent: Works without a kick drum present
• Shapeable: Custom curves beyond what compressors allow
• Latency-free: No processing delay

Popular LFO sidechain tools:

• Xfer LFOTool
• Cableguys VolumeShaper
• Nicky Romero Kickstart
• Native Instruments Duck

Practical Application

1. Insert a compressor on the bass track

2. Route the kick drum to the compressor's sidechain input

3. Set a low threshold so every kick triggers compression

4. Use a high ratio (4:1 or higher)

5. Set attack to fastest setting (instant engagement)

6. Adjust release to taste (start around 100ms)

7. Tune release until bass naturally swells between kicks

1. Bus all elements except kick and bass to a group

2. Insert compressor on this group

3. Sidechain to kick drum

4. Use gentler settings (2:1 to 4:1 ratio)

5. Adjust for subtle breathing rather than extreme ducking

1. Create a separate kick track that doesn't output to mix

2. Use this silent kick as sidechain trigger

3. Allows pumping effect without audible kick

4. Useful for breakdowns and ambient sections

Genre-Specific Approaches

Minimal techno often avoids sidechain compression entirely, preferring careful EQ and arrangement to prevent kick-bass conflict. The pumping effect contradicts minimal's spare aesthetic.

Common Mistakes

Excessive ducking sounds like the track is gasping for air. The effect should enhance groove, not dominate it.

If release doesn't match tempo, pumping feels out of sync. Calculate release time based on BPM: 60000 / BPM = milliseconds per beat. Set release to a fraction of this value.

Not every element needs to duck. Sidechaining drums to the kick creates a muddy, collapsed sound. Be selective about targets.

Sidechain compression can't fix poor arrangement. If kick and bass are clashing, consider octave separation or pattern changes first.