Pre-delay is one of the most overlooked reverb parameters, but it’s one of the most important. A small adjustment to pre-delay can dramatically change how a reverb sounds—from natural and intimate to spacious and separated.
If your reverb sounds like it’s burying your vocal or muddying your drums, the problem is usually pre-delay. Understanding what it does and how to set it is a core mixing skill.
What Pre-Delay Does
Pre-delay is the time between when a sound occurs and when the reverb reflections begin. It’s measured in milliseconds (ms).
Here’s how it works: When you send audio to a reverb plugin, the dry (original) signal comes through immediately. The reverb tail (the reflections and decay) doesn’t start right away—it starts after a delay, the pre-delay time. So there’s a gap between hearing the original sound and hearing the reverb.
This gap exists in real rooms. When you clap in a concert hall, the clap reaches your ear first, and the reflections from the walls reach you a moment later. The delay between them is the pre-delay of that room.
In a reverb plugin, you can set pre-delay to any value from near-zero (0 ms) to several hundred milliseconds. This control is crucial because it affects how the reverb interacts with the original sound and how clear (or muddy) the result is.
Pre-Delay in Milliseconds: The Range
0–20 ms: Pre-delay at the very short end. This sounds almost like the reverb is starting immediately, creating a lush, dense reverb tail. Natural-sounding for rooms with reflections that come back almost instantly (very small rooms or very close to a wall).
20–50 ms: Short pre-delay. This is the sweet spot for many sources. The reverb starts quickly enough to feel like a natural room, but late enough that the original sound remains clear. A 30 ms pre-delay on a vocal is a good starting point.
50–100 ms: Medium pre-delay. This creates more obvious separation between the original sound and the reverb tail. The original sound has time to land, and then the reverb blooms. Useful on instruments and drums.
100–200 ms: Long pre-delay. This creates a noticeable gap between sound and reverb, a “slapback” or “slap” effect. The reverb sounds like it’s coming from far away. Popular in hip-hop and some rock contexts.
200–500 ms: Very long pre-delay. This is a dramatic effect, almost like a delay that decays into reverb. You can clearly hear the gap between sound and effect. Use for creative, experimental effects.
Why Pre-Delay Matters for Clarity
Pre-delay directly affects how clear the original sound is, especially for transient-heavy sources like vocals and drums.
Consider a vocal: The opening consonants of words (like “P” or “T” sounds) have sharp, fast attacks. These transients define clarity and intelligibility. If pre-delay is too short or zero, the reverb tail starts so quickly that it clouds these transients. The listener can’t hear the initial consonant clearly because it’s already washing in reverb.
A pre-delay of 30–50 ms gives the transient time to come through clearly before the reverb starts. The consonant lands, and the reverb comes in behind it, enhancing the vocal without obscuring it.
Drums have the same issue. A kick drum’s impact comes from the fast attack of the beater hitting the head. If reverb starts immediately, it swallows that punch. A 20–30 ms pre-delay on drum reverb lets the impact shine through.
In general, sources with fast transients need more pre-delay. Sustained sounds (pads, strings, ambience) can use shorter pre-delay because there’s no fast attack to preserve.
Pre-Delay by Source
Pre-Delay for Vocals
Lead vocals typically use 30–60 ms of pre-delay. This preserves consonant clarity while letting the reverb enhance the body of the vocal. A 50 ms pre-delay is a good starting point.
Background vocals or harmonies might use similar pre-delay or slightly more (60–80 ms) to keep them slightly separated from the lead.
Spoken vocals (rap, spoken word) benefit from 40–80 ms pre-delay to maintain intelligibility in the reverb.
Pre-Delay for Drums
Kick drum: 10–20 ms, or sometimes none. The goal is to preserve the punch. Very short pre-delay or even 0 ms keeps the kick punchy.
Snare and clap: 20–30 ms to maintain the snap and tone of the hit.
Toms: 20–40 ms, depending on how articulate you want them.
Overheads or room mics: These already have ambient reverb captured, so pre-delay is less critical. 20–30 ms is typical.
Pre-Delay for Instruments
Acoustic guitar: 30–50 ms to preserve the pick attack and initial transient.
Electric guitar: 40–70 ms, depending on whether you want the reverb to blur sustain slightly or keep attacks clear.
Piano: 30–50 ms is standard. Longer pre-delay (up to 100 ms) can work if you want the reverb to trail behind the note rather than smother it.
Synth pads: These don’t have sharp transients, so pre-delay can be shorter (10–30 ms) or even zero.
Bass: Minimal reverb and minimal pre-delay. 10–20 ms if you’re using reverb at all, to preserve the fundamentals.
Syncing Pre-Delay to Your Song’s BPM
As an alternative to fixed millisecond values, you can sync pre-delay to your song’s tempo (BPM). This creates rhythmic effects.
A sixteenth-note pre-delay (125 ms at 120 BPM) creates a rhythmic “slap” that feels locked to the beat. Popular on vocals in hip-hop and pop.
An eighth-note pre-delay (250 ms at 120 BPM) creates more obvious separation and a pronounced echo effect before the main reverb.
A quarter-note pre-delay (500 ms at 120 BPM) is a dramatic effect, almost like a delay.
To set a synced pre-delay, use the BPM to milliseconds calculator to find the exact millisecond value for your desired note length, then enter it into the pre-delay parameter. Many modern reverb plugins have a “Sync” button that automatically calculates this for you.
Dialing In Pre-Delay: A Practical Guide
Step 1: Start with a Baseline
For most sources, start with a pre-delay of 30–50 ms. For drums, start at 20 ms. For ambient or sustained sources, try 10–20 ms.
Step 2: Listen to the Clarity
Turn the pre-delay up and down slowly. Listen to whether the original sound (the attack, the clarity, the transient) becomes clearer or more obscured.
If the source sounds muddy or cluttered, increase pre-delay. If it sounds too separate from the reverb (like two different effects), decrease pre-delay.
Step 3: Check the Reverb Interaction
The pre-delay should create a sense that the sound happens first, and the space around it (the reverb) comes second. The effect should be transparent—you hear the vocal clearly, then the space behind it.
Step 4: Fine-Tune by Ear
Start with your baseline and adjust by 5–10 ms increments until the balance feels right. The “right” setting depends on the source, the reverb type, and the mix context.
Step 5: Consider Sync
If your mix is rhythmically driven, consider syncing pre-delay to a beat subdivision. Learn how to sync pre-delay to your BPM for added rhythmic cohesion.
Frequently Asked Questions
What happens if pre-delay is too short?
The reverb starts before the transient of the original sound clears, muddying clarity. Vocals lose consonant definition, drums lose punch. Short pre-delay works for ambient or sustained sources but causes problems with articulate sources.
What happens if pre-delay is too long?
The sound and reverb separate too much, sounding disconnected. A very long pre-delay can sound like an echo or delay effect rather than a space. It can work creatively, but it usually breaks the sense of cohesion in a mix.
Should all reverbs in my mix have the same pre-delay?
Usually yes, if you’re using a shared reverb return (send reverb). All sources should have the same pre-delay to maintain the sense of a unified space. If using different reverbs for different sources, each can have its own pre-delay tailored to that source.
Can I set pre-delay to zero?
Yes, though it’s rarely optimal. Pre-delay of zero means the reverb and original sound start at the same time, which can muddy transients. Some ambient or lush effects use pre-delay at zero intentionally, but for clarity-focused mixing, 20+ ms is better.