Crash Course on Sidechain Compression, Parallel Compression, and Multiband Compression.

Welcome back to the fourth episode with Jatari.
In this episode, the focus is on three essential compression techniques used in modern audio production:

  • Sidechain compression
  • Parallel compression
  • Multiband compressors

The walkthrough begins with sidechain compression, breaking it down step by step using a very practical, audible setup. The goal is not theory for theory’s sake, but to hear exactly what’s happening and see how different compressor settings shape the sound.

Understanding Sidechain Compression Through a Practical Example

To demonstrate sidechain compression clearly, two tracks are used:

  • One bass track
  • One drum track

The bass line is intentionally designed as a long, stretched tone so the effect of sidechain compression is very obvious and easy to hear.

“I’ll show you the bass, which is just a really long stretched tone so you can really hear the effect of the sidechain.”

The drum track provides the rhythmic signal that will control the compression applied to the bass.

Setting Up the Sidechain in the DAW

The setup starts by inserting a compressor directly on the bass track. The key step is activating the sidechain input on that compressor.

Once the sidechain is enabled:

  • Other tracks can be sent into the key input of the compressor
  • In this case, the drum track is routed to the compressor on the bass

This means the bass is no longer compressed based on its own signal but based on the drums.

“What this does is it enables other tracks to be sent to the key input of this compressor.”

At this point, every time the drums hit, the compressor reacts and pushes the bass down.

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Hearing the Difference: Bass Without and With Sidechain Compression

Before engaging the compressor, the bass plays uninterrupted underneath the drums. Once the compressor is activated, the difference becomes immediately audible:

  • The drums come forward
  • The bass gets pushed back
  • The transient impact of the drums becomes more pronounced

This is the fundamental goal of sidechain compression in this context—making space.

Attack, Hold, and Release: Shaping the Ducking Effect

The character of the sidechain effect is entirely shaped by three main parameters:

  • Attack
  • Hold
  • Release

Initially, the compressor is set with:

  • A very fast attack
  • No hold time
  • A very fast release

This setup aggressively grabs the peaks of the drum hits and compresses the bass almost instantly.

“What that does is it really takes the peaks of the drums and compresses that basically out of the bass.”

Visually, this would look like small gaps being carved into the bass waveform wherever the drums hit.

Extending the Hold Time

By increasing the hold time, the compressor is instructed to stay compressed for a defined number of milliseconds after being triggered.

This results in:

  • Longer gaps in the bass
  • A more pronounced ducking effect
  • The bass stays pushed back even after the drum transient ends

“It stays in the compression a lot longer because this compressor has a hold function.”

Slowing Down the Release

Increasing the release time creates a smoother, more gradual return to the original bass level.

Instead of snapping back instantly, the bass fades back in:

  • Less abrupt
  • More musical
  • More controlled

This combination of longer hold and release produces a musical ducking effect, where the bass feels like it’s being gently pushed out of the way.

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What Happens With a Slow Attack?

When the attack time is increased:

  • The compressor reacts more slowly
  • It may miss the initial peaks of the drums
  • Less compression is applied overall

“The compressor is probably not really fast enough to grab these peaks.”

This results in a subtler effect, which can be useful depending on the style and material.

Applying Sidechain Compression to Voice and Bass

The same technique can be applied beyond drums and bass. To demonstrate this, a voice recording is introduced.

The setup:

  • Voice track recorded
  • Voice sent to the key input of the compressor on the bass
  • Bass compressed whenever the voice is present

Initially, without compression, the bass dominates the voice.

Once the compressor is activated, the bass ducks whenever the voice peaks.

“This is my voice when I’m compressing away the baseline.”

Fast Release and Its Side Effects

Using:

  • Fast attack
  • No hold
  • Very fast release

causes the compressor to jump rapidly in and out of compression.

This creates:

  • Audible pumping
  • A scattered, fluttering sound
  • An unpleasant, crowded texture

“You can hear that the compressor starts to scatter, to flubber.”

Visually, the waveform shows the compressor snapping back to the original signal between voice peaks, then compressing again almost immediately.

Why Fast Release Sounds Noisy on Voice

When the release is too fast:

  • The compressor recovers instantly between syllables
  • The bass level fluctuates rapidly
  • The result is distracting and fatiguing

“It jumps really fast here… It’s not really relaxing to listen to.”

This can work creatively for rhythmic material, but it becomes problematic for spoken word.

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Adjusting Settings for Voiceovers

For voiceovers, more relaxed settings are used:

  • Slightly longer attack
  • Hold time around 400 milliseconds
  • Longer release

This ensures that once the bass is compressed, it stays compressed through the vocal phrase instead of jumping back between words.

“Whenever this reaches the threshold, it’s staying compressed.”

The waveform now shows smooth, extended compression rather than jagged, rapid movement.

Visualizing Compression Recovery

With longer release times:

  • The compressor takes noticeably longer to recover
  • The bass returns gradually after the voice stops
  • The compression behavior becomes clearly visible

“That’s how long it takes to recover basically from that compression.”

This creates a much more natural listening experience.

The Result: A More Relaxed Vocal Mix

When the adjusted settings are applied:

  • The voice sits comfortably on top
  • The bass no longer competes
  • The overall sound feels calmer and more controlled

“That sounds a lot more at ease, basically.”

This approach is especially effective for:

  • Voiceovers
  • Spoken content
  • Narration over music or sound design

Musical vs. Spoken Applications

Different source material benefits from different settings:

  • Fast release and aggressive ducking
    • Drums and bass
    • Synths and rhythmic elements
    • Creative, musical pumping effects
  • Longer release and smoother compression
    • Voiceovers
    • Dialogue
    • Spoken content over music

“Be careful when you do that with voiceovers.”

What’s Coming Next

The episode continues with a deeper discussion on:

  • Parallel compression
  • Multiband compression

These techniques build on the same principles but introduce new ways to control dynamics across an entire mix.