Compression is the dynamics processing tool that controls the volume range of audio. In beat production, compression makes drums punchier, bass more consistent, melodies more present, and the overall mix more cohesive. Logic Pro's Compressor plugin includes seven circuit models, each emulating a different hardware compression topology with distinct sonic characteristics. Understanding which model to use, when to compress, and how to set the parameters separates amateur mixes from professional ones. For Audeobox battle producers, compression is what makes drums hit through phone speakers and keeps the mix glued together at high loudness levels.
Compression Basics
A compressor reduces the volume of audio that exceeds a set threshold. The amount of reduction is controlled by the ratio. A 4:1 ratio means that for every 4 dB the signal goes above the threshold, only 1 dB passes through. The result is a signal with a smaller dynamic range: the loud parts are quieter, the quiet parts are (relatively) louder.
The five core compressor parameters:
- Threshold: The level above which compression begins. Lower thresholds mean more of the signal is compressed.
- Ratio: How much the signal is reduced above the threshold. 2:1 is gentle, 4:1 is moderate, 8:1+ is heavy.
- Attack: How quickly the compressor engages after the signal exceeds the threshold. Measured in milliseconds.
- Release: How quickly the compressor stops compressing after the signal drops below the threshold. Measured in milliseconds.
- Makeup Gain: Compensates for the volume reduction caused by compression. Add enough gain to match the compressed output to the uncompressed input level.
Logic Pro Compressor Models
Logic Pro's Compressor includes seven circuit models. Each model processes audio differently, adding its own sonic character. Select models from the dropdown at the top of the Compressor interface.
| Model | Type | Character | Best For |
|---|---|---|---|
| Platinum Digital | Digital | Transparent, clean, precise | Mastering, vocals, anything needing transparent compression |
| Studio VCA | VCA | Punchy, tight, modern | Drum bus, mix bus, general mixing |
| Classic VCA | VCA | Aggressive, colored, vintage | Parallel compression, character processing |
| Studio FET | FET | Fast, aggressive, bright | Drums, percussion, aggressive bass |
| Vintage FET | FET | Warm, saturated, vintage | Bass guitar, vocals, character compression |
| Vintage Opto | Optical | Smooth, slow, musical | Bass, vocals, gentle leveling |
| Vintage VCA | VCA | Warm, classic bus compression | Mix bus, mastering, group processing |
The difference between models is not just EQ coloring. Each model has different attack and release behavior, harmonic distortion characteristics, and gain response curves. The FET models react fastest, making them ideal for transient-heavy material like drums. The Opto model reacts slowest, creating smooth, transparent compression that suits sustained sources like bass and vocals.
Compressor Settings Explained
Attack Time: The Most Important Setting
Attack time determines whether the compressor catches the initial transient of a sound. This single parameter has the biggest impact on how compression affects the character of your audio:
- Fast attack (1-10ms): Catches the transient. Reduces punch and impact. Makes sounds smoother and more controlled. Use on bass and sustained sounds where you want level consistency without sharp peaks.
- Medium attack (10-30ms): Lets some transient through before engaging. Balances punch and control. The most versatile setting for general mixing.
- Slow attack (30-100ms): Lets the full transient pass, then compresses the sustain. Preserves or enhances punch. Use on drums and percussion where you want maximum impact.
Release Time
Release controls how quickly the compressor stops compressing after the signal drops below the threshold:
- Fast release (10-50ms): Compressor recovers quickly. Preserves the natural dynamics of each individual hit but may cause pumping on rhythmic material.
- Medium release (50-200ms): Smooth recovery. The most natural-sounding release for most material.
- Slow release (200-500ms+): Compressor stays engaged between hits. Creates a more consistent level but can sound squashed on rhythmic material.
- Auto: Logic Pro adjusts release time automatically based on the input signal. Convenient and sounds good on most material.
Knee
The Knee parameter controls how gradually compression engages as the signal approaches and crosses the threshold:
- Hard knee (0.0): Compression engages abruptly at the exact threshold. More audible compression effect. Works for drums and aggressive processing.
- Soft knee (0.5-1.0): Compression engages gradually around the threshold. More transparent. Works for bus and master compression where subtlety matters.
Compression by Element
Kick Drum
Model: Studio FET. Ratio: 4:1. Attack: 20-30ms (slow enough to let the transient through). Release: 50-80ms (recover before the next kick). Gain reduction: 3-6 dB. The FET's fast response handles the kick's sharp transient while the slow attack preserves the punchy attack.
Snare
Model: Studio FET. Ratio: 4:1. Attack: 5-15ms. Release: 80-120ms. Gain reduction: 3-6 dB. A slightly faster attack than the kick catches some of the snare transient, creating a more controlled crack without losing all the impact.
Bass / 808
Model: Vintage Opto. Ratio: 3:1. Attack: 15-25ms. Release: 100-150ms (or Auto). Gain reduction: 3-5 dB. The Opto model's smooth, slow response evens out bass dynamics without adding aggressive coloring. The bass stays consistent in level across the entire beat.
Melody / Synth
Model: Platinum Digital. Ratio: 2:1. Attack: 15-25ms. Release: 100-150ms. Gain reduction: 2-4 dB. Transparent compression that levels the melody without changing its character. The Platinum model adds no coloring, letting the original synth tone shine through.
Drum Bus
Model: Studio VCA. Ratio: 4:1. Attack: 10-15ms. Release: 50-80ms. Gain reduction: 3-6 dB. VCA bus compression glues the drum kit together, making individual elements sound like one cohesive instrument. This is the most impactful single compression move in beat mixing.
Mix Bus
Model: Vintage VCA. Ratio: 2:1. Attack: 30ms. Release: Auto. Gain reduction: 1-3 dB. Gentle glue compression that binds the entire mix. More than 3 dB of gain reduction on the mix bus indicates individual elements are too dynamic and need individual compression first.
Multipressor Guide
The Multipressor splits the audio into up to four frequency bands, each with independent compression settings. Load it from Dynamics > Multipressor.
Use the Multipressor when single-band compression creates unwanted side effects. For example, compressing a drum bus with a standard compressor causes the loud kick to trigger gain reduction that also reduces the hi-hat volume. The Multipressor lets you compress the bass range (where the kick lives) independently from the high range (where the hi-hats live).
Multipressor Settings for Drum Bus
- Low band (20-200 Hz): Ratio 3:1, attack 10ms, release 80ms. Controls kick and 808 dynamics.
- Mid band (200-4000 Hz): Ratio 2:1, attack 15ms, release 100ms. Controls snare body and melody presence.
- High band (4000-20000 Hz): Ratio 3:1, attack 5ms, release 50ms. Controls hi-hat energy and high-frequency transients.
Adjust crossover frequencies by dragging the band dividers in the Multipressor display. Set them to avoid splitting important elements across bands. The kick should be entirely within the low band, the snare body within the mid band.
Parallel Compression
Parallel compression blends a heavily compressed copy of the audio with the original uncompressed signal. The result is drums that sound both punchy (from the uncompressed transients) and full (from the compressed sustain).
- Create a Send from your drum bus to an auxiliary bus.
- Load the Compressor on the auxiliary with aggressive settings: Classic VCA model, 10:1 ratio, fast attack (3ms), fast release (30ms), 10-15 dB gain reduction.
- Set the auxiliary fader low. Blend the compressed signal under the original at about 30-40% level.
- Play the beat and gradually raise the parallel compression send until the drums sound fuller and more energetic without losing their transient attack.
- The compressed signal fills in the quiet parts (ghost notes, room sound, sustain tails) while the original signal provides the clean transients.
Sidechain Compression
Sidechain compression triggers the compressor on one track using the signal from a different track. The most common use in beat production is sidechaining the 808 or bass to the kick drum so the bass ducks when the kick hits.
- Load the Compressor on the 808/bass track.
- Click the Sidechain dropdown at the top right of the Compressor window.
- Select the kick drum track as the sidechain source.
- Set the attack to 1-5ms (the 808 should duck immediately when the kick hits).
- Set the release to 30-80ms (the 808 should return to full volume quickly after the kick transient passes).
- Set the ratio to 4:1 to 8:1 for noticeable ducking.
- Adjust the threshold until you see 4-8 dB of gain reduction on each kick hit. Too little and the kick does not punch through. Too much and the 808 disappears.
Sidechain compression can also create rhythmic pumping effects. Use it on pads or synths sidechained to the kick for a pulsing, breathing texture that locks to the groove. Set a slower release (100-200ms) for a more obvious pumping effect.
FAQ
Which Logic Pro compressor model should I use for drums?
For individual drum hits (kick, snare), use the Studio FET or Vintage FET for fast, punchy compression. For the drum bus, use Studio VCA for transparent glue that tightens the drums without coloring them. For parallel drum compression, use Classic VCA for aggressive, colored compression blended under the dry drums. The FET models react fastest, making them ideal for percussive material.
What does the attack setting do on the Logic Pro Compressor?
Attack controls how quickly the compressor reacts after the signal exceeds the threshold. Fast attack (1-10ms) catches the initial transient, reducing punch and impact. Slow attack (20-50ms) lets the transient pass through uncompressed, preserving punch while controlling the sustain. For drums, slower attack preserves the hit. For bass, medium attack balances punch and control.
How much compression should I use on beats?
A good rule: 3-6 dB of gain reduction on individual elements, 2-4 dB on the drum bus, and 1-3 dB on the mix bus. If you need more than 6 dB on an individual element, the source level is probably too dynamic and needs a gain adjustment before compression. Over-compression kills dynamics and makes beats sound flat and lifeless.
What is the difference between the Compressor and Multipressor in Logic Pro?
The Compressor is a single-band dynamics processor that affects the entire frequency range equally. The Multipressor splits the signal into up to four frequency bands, each with independent compression settings. Use the Compressor for general dynamics control on individual tracks and buses. Use the Multipressor when you need to control specific frequency ranges independently.
How do I set up sidechain compression for kick and 808 in Logic Pro?
Load the Compressor on the 808 track. Click the Sidechain dropdown at the top of the Compressor and select the kick track as the sidechain input. Set the threshold so the compressor engages when the kick hits. Use a fast attack (1-5ms), fast release (30-50ms), and a ratio of 4:1 to 8:1 for noticeable ducking. Adjust until the kick punches through cleanly without the 808 disappearing.