The impulse response (IR) is the acoustic fingerprint of a space — recorded by firing a starter pistol or sine sweep, then capturing every reflection, decay, and resonance. Adjust room parameters below to see how the IR changes.
IMPULSE RESPONSE ANATOMY
Direct Sound arrives first at t=0 — the unmodified signal. Early Reflections (5–80ms) give the brain cues about room size. Late Reverberation (80ms+) is the diffuse wash that defines the room's character. The RT60 is how long the tail takes to decay 60dB.
Section 02
Schroeder Reverberator
In 1962, Manfred Schroeder published a landmark paper defining artificial reverberation using comb filters and allpass filters. This architecture became the blueprint for all digital reverb that followed.
SIGNAL FLOW DIAGRAM
Comb Filters create echoes at specific delay times — their feedback creates the density of the reverb tail. Allpass Filters scatter the echo density without changing perceived frequency content. Four parallel combs + two series allpass = the first practical digital reverb.
Section 03
Plate Reverb — EMT 140
The EMT 140, introduced in 1957, is a large steel plate (2m × 1m) suspended by springs in a frame. A transducer drives vibrations into the plate; pickups capture the result. Click the plate to excite it.
EMT 140 PLATE — CLICK TO EXCITE
The plate reverb became the studio standard throughout the 60s and 70s. Its characteristic smooth, dense tail with no flutter echo made it ideal for vocals and drums. Phil Spector, Motown, and Abbey Road all relied on plate reverb.
Section 04
Pre-Delay — The Singer and the Wall
Pre-delay is the gap between the dry signal and the first reverb reflection. It creates perceptual separation — the brain hears the direct sound clearly before the reverberant wash begins.
REFLECTION PATH VISUALIZER
5.1mWall Distance
30msPre-Delay
RoomCharacter
Rule of thumb: Pre-delay under 20ms = intimate/small room. 20–50ms = medium hall. 50–100ms = large space. Above 100ms you start to hear a distinct echo. Set pre-delay to roughly 1ms per meter of perceived space. Formula: d = (t × 343) ÷ 2
Section 05
RT60 Physics Lab
RT60 is the time required for a sound to decay by 60 decibels after its source stops. Sabine's formula (1900) links room volume, surface area, and absorption coefficient to predict RT60. Adjust the parameters to see how the decay curve changes.
DECAY CURVE — LOG SCALE
1.01sRT60
StudioSpace Type
Sabine Formula: RT60 = 0.161 × V / (S × α) |
Anechoic ≈ 0.01s · Recording Studio ≈ 0.2s · Concert Hall ≈ 2.0s · Cathedral ≈ 6s+
Section 06
Frequency-Dependent Decay
Real rooms don't decay uniformly across all frequencies. High frequencies are absorbed faster by air and soft materials. Low frequencies sustain longer, often much longer. The spectrogram below shows this behaviour for different surface materials.
SPECTROGRAM — TIME × FREQUENCY
BAND DECAY CURVES
Carpet & Curtains absorb high frequencies rapidly, creating warm, dark reverb tails. Concrete & Glass reflect HF efficiently, producing bright, harsh reverb. Wood offers a balanced mid-frequency resonance — the classic concert hall material.
Section 07
Gated Reverb Designer
Gated reverb was born in 1979 when Hugh Padgham accidentally left a noise gate open while recording Phil Collins' drums at Townhouse Studio. The result — an enormous reverb tail violently cut off — became the defining sound of the 1980s.
GATE ENVELOPE VISUALIZER
"In the Air Tonight" (1981) · "Don't Give Up" (1986, Peter Gabriel & Kate Bush) · "When Doves Cry" (1984) — all define gated reverb. The gate slams shut before the natural decay, creating that explosive, unnatural cut. The trapdoor above animates the gate closure.
Section 08
Convolution vs. Algorithmic
Convolution reverb captures the exact acoustic fingerprint of real spaces by convolving your signal with a recorded impulse response. Algorithmic reverb builds artificial rooms from mathematical models — controllable, but approximate.
CONVOLUTION — REAL IR
ALGORITHMIC — SYNTHETIC IR
94%Spectral Similarity
Convolution: CPU-intensive, captures every physical nuance — phase relationships, flutter echoes, resonant modes. No parameter control. Algorithmic: Real-time, fully adjustable, consistent. Cannot replicate physical irregularities. Best for creative control.
Modern reverbs (Valhalla, Lexicon 480L) blur this distinction.
Section 09
Eno System — Generative Feedback Reverb
In 1975, Brian Eno discovered that feeding tape loops of different lengths through a mixer — each loop a slightly different length — created self-generating ambient textures that never exactly repeated. Discreet Music was born.
FEEDBACK LOOP SYSTEM
"In 1975, Eno discovered that accidents + systems = music." The tape loop system worked because no two loops were the same length — their phase relationships drifted continuously, producing an endless non-repeating texture. This principle underlies all modern generative and ambient music.
Section 10
Emotion Map — Cartographic Reverb Space
Every reverb has an emotional address. Drag the cursor to blend between spaces. Parameters interpolate in real time. Click any named zone to jump directly.
REVERB EMOTION SPACE — DRAG TO EXPLORE
1.2sRT60
20msPre-Delay
40%Damping
RoomCharacter
Section 11
Space Architects
Ten artists who transformed space from acoustic property into musical instrument — treating reverb not as decoration, but as compositional material.
Section 12
Glossary
24 essential terms for understanding reverberation, acoustics, and spatial audio processing.
WAVGEN MUSIC WORLD 05 — REVERB LAB | SPACE IS THE FINAL INSTRUMENT