Welcome to the second part of this audio-tutorial series on compression. In the first part, the focus was on the common functions of compressors—how they work and what each control does:

• Threshold
• Ratio
• Attack time
• Release time
• Make-up gain

This second part shifts away from what the controls are and moves toward how compressors are actually used in real mixing situations. The emphasis here is on settings, application techniques, and practical workflows, including:

• New York drum compression
• Parallel compression
• Side-chain (key-input) compression

The goal is not to provide fixed recipes but to explain how and why different compression approaches are chosen, depending on the sound and context of the mix.

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How Compressors Are Commonly Used in a Mix

Compressors as Insert Effects

Most of the time, compressors are used as insert effects on individual tracks in a multitrack recording. This means the compressor affects only one sound, not the entire mix.

For example, in a typical band recording, you might want to dynamically control:

• The kick drum
• The snare drum
• The bassline
• A vocal track

Each of these elements behaves differently, so they all require different compression settings. Because of that, compressors are inserted on each respective channel, allowing precise control over the dynamics of each sound.

One compressor setting will not work equally well for a kick drum, a snare, a bass, and a vocal.

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Compression on Group Tracks

Compressors are not limited to single channels. They are also commonly used on group tracks (or buses).

A typical example is drum bus compression, where all individual drum tracks are routed to a single group channel and compressed together. This allows you to:

• Control the overall dynamics of the drum kit
• Add cohesion and consistency
• Shape the combined drum sound rather than individual hits

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Compression During Mastering

Compression is also applied during mastering, where it affects the entire mix. In this case, the compressor works on the stereo output and is used more subtly, focusing on overall dynamic control rather than individual elements.

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The Myth of the “Best Compressor Setting”

One of the most common questions is

• “What is the best compressor setting for my compressor?”
• “Can I get a preset for this vocal track?”

The reality is simple:

There is no universal compressor preset that always works.

A compressor must be set according to:

• The sound you want to achieve
• The specific mix
• The project you’re working on
• The material that already exists in the mix

Because every mix is different, it’s impossible to say:

“If you compress it like this, it will be good.”

Compression is always context-dependent.

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Guidelines, Not Guaranteed Formulas

While there are no fixed rules, there are guidelines that can help you get started. These are starting points, not success-guaranteed formulas.

The most important general idea is this:

Compressors should be set differently for sustained sounds than for transient sounds.

Sustained vs. Transient Material

• Sustained sounds
  Examples include vocals, pads, strings, and bass notes that ring out.
• Transient sounds
  Examples include kick drums, snare hits, percussion, and short plucks.

Each of these categories responds differently to compression, so attack times, release times, and ratios often need to be adjusted accordingly.

Always keep in mind:

• These settings are guidelines
• You will almost always need to tweak them
• The final decision should be based on what you hear

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Understanding the Knee Setting

What Is the Knee Control?

One compressor function not covered earlier is the knee setting, which is available on certain compressors.

The knee control lets you choose between:

• Soft knee
• Hard knee
• Or a position somewhere in between (on compressors with a knee slider)

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Soft Knee Compression

With a soft knee, the compressor begins applying compression gradually, even before the signal fully reaches the threshold.

• The ratio increases slowly
• Compression is applied more gently
• The effect is smoother and less noticeable

This helps to smooth out dynamic changes without making the compression obvious.

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Hard Knee Compression

With a hard knee, compression is applied immediately once the signal reaches the threshold.

• The ratio kicks in exactly as set
• The effect is more obvious
• You can clearly hear when the compressor starts working

Hard knee compression is more noticeable, while soft knee compression is more subtle and smooth.

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The New York Drum Compression Technique

Also Known As Parallel Compression

The New York drum technique goes by many names:

• New York drum compression
• New York repression
• Parallel compression

Regardless of the name, the concept is the same.

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How New York Compression Works

This technique combines:

• A dry (uncompressed) drum signal
• A heavily compressed drum signal

Both signals are played at the same time.

The result is a drum sound with:

• More body
• More weight
• Preserved transients from the dry signal
• Added density from the compressed signal

You don’t replace the original drums—you blend them with the compressed version.

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Listening Stages in Parallel Compression

The typical way to demonstrate this technique is by listening to:

1. The original drum track
2. The heavily compressed drum track
3. The combined signal (the New York drum track)

It’s the combination that creates the characteristic sound.

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Side-Chain (Key-Input) Compression

What Is Side-Chain Compression?

Another important concept is the side chain, also known as the key input.

A side-chain allows a compressor to be controlled by a different signal than the one being compressed.

This makes it fundamentally different from standard compression.

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Voice-Over and Music Ducking Example

A common use case involves:

• A music track
• A voice-over track

The goal is simple:

When the voice-over speaks, the music should become softer.

To achieve this:

• A compressor is placed on the music track
• The vocal track is sent to the key-input of that compressor

When the vocal signal becomes active, it triggers the compressor, reducing the level of the music automatically.

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The Audible Result

In this setup:

• The vocals push the music away
• The music ducks in level while the voice speaks
• The effect often creates a compressed, pumpy sound

This is commonly heard in:

• Radio voice-overs
• Broadcast content
• Spoken-word mixes over music

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The Range of What Compression Can Do

Compression offers a lot of possibilities, and there is definitely a lot to it. From subtle dynamic control to obvious pumping effects, compressors can shape sound in many different ways depending on how they’re set and applied.

In the next part of this tutorial series, the focus shifts to

• Different compressor plugins
• Listening to the distinct differences in sound between them

The emphasis there is not on controls but on how different compressors actually sound when used in practice.