Free Reverb Pre-Delay Calculator

Pre-delay is the time gap between the original (dry) sound and the first reflections of the reverb. In a real room, sound travels from a source to the nearest wall and back before you hear the first reflection. Pre-delay in a reverb plugin simulates this gap.

Why does it matter? Without pre-delay, the reverb starts immediately on top of the dry signal, which can smear transients and make sounds feel distant and muddy. By adding even 10–30 ms of pre-delay, you let the original attack come through clearly before the reverb washes in. This is especially important for percussive sounds like kicks, snares, and hi-hats in electronic music.

The Haas effect (also called the precedence effect) tells us that sounds arriving within about 1–40 ms of each other are perceived as a single fused event. Setting your pre-delay within this window creates a sense of space without an obvious echo. Go beyond 40 ms and you start hearing a distinct slapback delay before the reverb tail.

In practice, shorter pre-delays (5–20 ms) keep things tight and controlled, while longer pre-delays (30–80 ms) create more dramatic separation. The right choice depends on the room size, the tempo, and the genre.

1. Enter the BPM of your track using the number input or click a preset button.
2. Select a room size or reverb style that matches the sound you are going for (e.g., Tight Room for a dry club mix, Cathedral for ambient pads).
3. Read the optimal pre-delay value and the musical note subdivisions synced to your BPM. The recommended value is highlighted in violet.
4. Check the decay time section for suggested RT60 ranges and musical decay values. Use the recommended note length so the reverb tail clears before the next beat.
5. See the quick reference card for a one-line summary you can copy to your notes.
6. Click any value to copy it to your clipboard and paste it directly into your DAW’s reverb plugin.

RT60 (Reverb Time) is the time it takes for the reverb tail to decay by 60 dB — essentially, how long until the reverb is inaudible. A small bathroom might have an RT60 of 0.3 seconds; a concert hall might be 2–3 seconds; a cathedral can exceed 5 seconds. In your DAW, the “Decay” or “Reverb Time” knob controls this.

Pre-delay sets the gap before the reverb starts. As discussed above, it preserves transient clarity. Most reverb plugins have a dedicated pre-delay knob measured in milliseconds.

Early reflections are the first bounces of sound off the nearest surfaces. They give the listener cues about room size and shape. Many reverb plugins let you control the level and timing of early reflections separately from the diffuse tail.

Diffusion controls how quickly the individual reflections blur together into a smooth tail. High diffusion creates a lush, smooth wash (good for pads and ambient textures). Low diffusion keeps individual reflections more distinct, which can sound more natural or create flutter effects.

Damping / High-Frequency Decay controls how quickly high frequencies die out in the reverb tail. In real rooms, high frequencies are absorbed by soft surfaces faster than lows. Adding damping makes the reverb sound warmer and more natural, preventing harsh sibilance buildup.

• Sidechain your reverb return — route your kick to a compressor on the reverb bus. This ducks the reverb on every kick hit, keeping low-end clean while maintaining a lush tail between hits.
• Use pre-delay to preserve transients — even 10–15 ms of pre-delay can prevent the reverb from smearing a snare or clap. The dry hit comes through first, then the reverb fills in behind it.
• Match decay time to tempo — if your reverb tail is still audible when the next beat hits, it creates a muddy overlap. Use this calculator to find a musical note value that lets the tail decay in time.
• High-pass the reverb return — cut everything below 200–400 Hz on the reverb bus to prevent low-frequency buildup that muddies the mix. This is especially important for bass-heavy genres like Tech House and Techno.
• Use sends, not inserts — send multiple tracks to the same reverb bus to create a cohesive space. This also saves CPU and gives you more control over the wet/dry balance per channel.
• Automate reverb for transitions — increase the send level or decay time during breakdowns and drops to add drama. Automate it back down when the groove returns to keep energy tight.
• Layer different reverb types — use a short plate on drums for punch and a longer hall on synths for depth. This lets each element sit in its own space without competing.
• Check in mono — wide reverbs can sound impressive in stereo but cause phase cancellation in mono. Always check your mix in mono to make sure the reverb does not disappear or cause comb filtering.