Free Tool
Every acoustics tool hands you a number in seconds and leaves you to imagine what it means. This one plays it. Pick two rooms and listen to the same sound in both.
The classic room test, and completely dry to begin with — so what you hear is entirely the room we put it in.
0.70s
Some soft furnishing, some hard floor.
0.30s
What the panel calculator aims a recording space at.
Play them back to back and the difference is not really “more echo.” It's that in the livelier room the sound keeps arriving after the thing that made it has stopped. On a clap you hear it as a tail. On a voice you hear it as the consonants smearing into each other — which is exactly why a room can be perfectly pleasant to sit in and still make you sound amateur on a recording.
Try 0.2 against 0.45 as well. Both are perfectly usable rooms, and the gap between them is smaller than most people expect. Then try 0.7 against 1.8, where the difference stops being subtle.
Reverberation time — RT60 — is the number of seconds it takes for sound in a room to fade by 60 decibels, which in practice means fading to inaudible. It is the single most useful number for describing how a room sounds, and it is almost impossible to interpret until you have heard a few.
A treated voice booth sits near 0.2 seconds. A comfortable furnished office is around 0.45. A living room with some soft furnishing and some hard floor lands near 0.7. A room with wood or tile floors, bare walls and large windows runs past 1.1, and a completely empty room can exceed 1.8 — which is why houses sound so strange on moving day and normal again a week later.
The room here is synthesised rather than recorded. An impulse response is built for the reverberation time you choose — a direct sound, a short gap, a handful of early reflections that give the space its sense of size, then a decaying noise tail whose high frequencies fade faster than its low ones, because that is what happens in real rooms. Your chosen sound is convolved with it.
Both versions are normalised to the same peak level on purpose. A livelier room genuinely carries more energy, so without that step the reverberant version would simply sound louder, and loudness is not the difference worth demonstrating.
This is a plausible room rather than a measurement of a specific one. Two real rooms with identical reverberation times still sound different, because shape and the distribution of absorption matter too. What carries across is the decay, which is the part the number describes.
If you record yourself, the result already contains your room. Removing it would mean dereverberation, which is an unsolved problem in the general case and certainly not something to do quietly in a browser and present as truth. So this tool adds a room to whatever you give it.
If you want to know what your own room measures, the studio sound check works it out from a ten-second recording. Then come back here, put that number on one side and your target on the other, and hear the gap you would be buying.
Once a target sounds worth having, the panel calculator works out what reaching it costs in panels, and the rug size calculator covers the floor — usually the cheapest large improvement available.