RT60 is the standard measure of reverberation time — the number of seconds it takes for a sound to decay by 60 decibels after the source stops. When people ask what is RT60, this is the core idea: it’s a single number that tells you how “live” or “dead” a room sounds. A long RT60 means a reverberant, echoey space; a short RT60 means a controlled, tight one.
For a home studio you generally want a fairly short, even RT60 so reflections don’t smear what you record or mix. But you don’t want it bone-dry either, which sounds unnatural and fatiguing.
What Is RT60 Measuring?
When a sound stops, it doesn’t cut off instantly — the reflections bouncing around the room keep feeding energy back, and the sound fades over time. RT60 captures how long that fade takes to drop by 60 dB, which is roughly from a normal speaking level down to near silence. A large, hard-surfaced room (think a tiled bathroom or a church) has a long RT60. A heavily furnished, soft room has a short one. It’s a direct consequence of how sound behaves in a room, specifically the reverberation tail.
RT60 Varies by Frequency
One number rarely tells the whole story, because RT60 changes across the frequency spectrum. Most rooms decay slowly at low frequencies (bass hangs around longer because room modes ring on) and faster at high frequencies (soft furnishings and air absorb treble quickly). That’s why a measurement plots RT60 across many frequency bands rather than giving a single figure. An uneven decay — boomy bass, dead treble — sounds worse than a slightly longer but even one.
What RT60 Should You Aim For?
There’s no single correct value, but for a small home control room or recording space, a fairly short and even reverberation time across the band is the goal — long enough to feel natural, short enough to keep reflections from blurring detail. Rather than chasing an exact target, aim for two things:
- Evenness. The decay should be similar across low, mid and high frequencies, with no big bass overhang.
- Control without deadness. Over-treating a room with thick absorption everywhere can make it sound lifeless and tiring to work in.
Recording spaces and control rooms have slightly different needs, and very small rooms are usually controlled more tightly than larger ones. A small vocal booth or close-mic recording space benefits from a shorter decay, because you want to capture the source and not the room. A control room where you make mixing decisions wants a balanced, even decay so what you hear translates to other systems. Bigger rooms can carry a slightly longer tail without feeling cluttered, which is part of why commercial live rooms sound the way they do.
How Room Size and Surfaces Change RT60
Two things drive reverberation time: the volume of the room and how absorbent its surfaces are. A bigger room gives sound more distance to travel between reflections, so energy lingers longer. Hard, flat surfaces — bare plaster, glass, tile, laminate flooring — reflect almost everything back, building up a long tail. Soft, porous surfaces — carpet, curtains, sofas, bookshelves, acoustic panels — absorb energy and shorten it. This is why an empty room sounds cavernous and the same room sounds tame once it’s furnished. Before buying any treatment, look honestly at what your room is made of: a converted bedroom with carpet and a wardrobe is already partway there, while a tiled garage starts from a much harder, brighter baseline.
How to Measure RT60
You measure RT60 with a calibrated measurement microphone such as the miniDSP UMIK-1 and free software like Room EQ Wizard (REW). REW plays a test signal, records the decay, and produces an RT60 plot across frequency bands. This shows you whether your problem is a long overall tail, a boomy low end, or harsh midrange reflections — which tells you what kind of treatment you need. If you’ve never run it before, our walkthrough on how to use Room EQ Wizard covers the whole process step by step.
Measure before you treat and again afterwards, so you have a baseline to compare against. Place the microphone roughly where your head sits while mixing, take a few measurements at slightly different positions, and average them rather than trusting a single reading. The point of measuring is not to hit a textbook number but to expose the shape of the problem: a single tall spike in the low end points you towards bass traps, while a long, even tail across the mids and highs points you towards broadband panels.
How to Control RT60
To shorten and even out reverberation time:
- Porous absorbers (mineral wool panels like Rockwool or Owens Corning 703) reduce mid and high-frequency reflections.
- Bass traps in the corners shorten the long low-frequency decay caused by room modes.
- Diffusion keeps a room from sounding dead while still controlling harsh single reflections.
Our acoustic treatment for home studios guide walks through where to place each. And remember: RT60 and treatment are about the sound inside the room. Stopping sound from leaving is a separate job — see soundproofing vs acoustic treatment. For the bigger picture, start with what room acoustics is.
Common Mistakes With RT60
The mistakes people make with reverberation time tend to repeat. A few worth avoiding:
- Treating only the high end. Thin foam and a few panels tame harsh treble reflections, but the low-frequency tail usually dominates the problem and needs much thicker absorption to touch.
- Over-damping the room. Covering every surface in absorption drags the high end down faster than the low end, leaving a dull, boxy space that’s tiring to work in and still boomy at the bottom.
- Chasing a single number. A flattering average RT60 can hide a nasty bass overhang. Always look at the decay across frequency, not just one figure.
- Confusing it with soundproofing. Shortening RT60 makes a room sound better inside; it does almost nothing to stop sound passing through walls. Those are different problems with different solutions.
Frequently Asked Questions
Why is it called RT60 specifically?
Because it measures the time for sound to decay by 60 decibels. That range was chosen historically as a meaningful drop from a loud sound to near inaudibility. In practice, software often measures a smaller decay and extrapolates to 60 dB.
Is a lower RT60 always better?
No. Too short an RT60 makes a room sound dead and unnatural, which is tiring and can mislead your mixing decisions. The goal is a controlled, even decay, not the shortest possible one.
Can acoustic foam fix a long RT60?
Thin foam can shorten the high-frequency decay but does little for the low-frequency tail, which is usually the bigger problem. You need thick bass traps for the low end and proper panels for the mids and highs.
How is RT60 different from echo?
An echo is a single, distinct repeat of a sound that you can pick out separately, usually off a far surface. RT60 describes the smooth build-up and gradual fade of many overlapping reflections in a room, which you hear as reverberation rather than as separate repeats. Most small rooms have a reverberation problem, not a true echo.
