RT60 is the time in seconds it takes for sound to decay by 60 dB (decibels) after a loud sound source stops. In a small home studio, that might be 0.3 seconds. In a cathedral, it could be 5+ seconds. RT60 directly affects how you hear your mix—a short RT60 makes mixes sound dry and intimate, while a long RT60 makes them sound spacious and washy. Getting RT60 right is one of the single biggest factors in making your room usable for mixing and recording.
A well-treated room has consistent RT60 across the frequency spectrum, though in practice bass frequencies often have longer decay times than midrange and treble. Inconsistency is the real problem: a room where bass rings for 1.5 seconds while midrange dies in 0.3 seconds will make every mix sound boomy and unclear.
Ideal RT60 by Room Type and Size
Home Studios and Mixing Rooms
A home studio used for mixing and production should target an RT60 of 0.3–0.5 seconds across the midrange (500 Hz–4000 Hz). This range gives you enough reflection to hear imaging and stereo separation without excessive reverb masking detail. You’ll hear punch in drums, clarity in vocals, and presence in cymbals without the room sounding dead or boxy.
Smaller rooms (under 150 sq ft) often lean toward the shorter end (0.3–0.4 sec) because the proximity of walls makes reflections more problematic. Larger rooms (200–400 sq ft) can handle 0.4–0.5 sec because reflected sound arrives with more delay and feels more natural.
Vocal and Instrument Recording Booths
A dedicated recording booth—where you’re capturing performances rather than mixing—can have slightly longer RT60 because you want to preserve some of the natural space and warmth. Target 0.4–0.6 seconds for vocals, 0.5–0.8 seconds for drums and acoustic instruments. This allows the room to add subtle character to the recording without sounding like a dead, clinical closet. The performer feels like they’re in a real space, not recording into a pillowcase.
Larger Mixing/Mastering Suites
Professional mixing and mastering rooms (300–600 sq ft) often target RT60 of 0.4–0.6 seconds to balance clarity with liveliness. These rooms are usually treated symmetrically and precisely because the stakes are high—the mixes made here go to the world. Deviations in RT60 of more than 0.1 seconds between octave bands raise red flags.
Podcast and Voice-Only Spaces
For voiceovers, podcasts, and spoken-word recording, shorter RT60 (0.2–0.4 sec) is better. Long reverb tails make speech hard to understand and require more post-processing to remove. A tight, dead-sounding booth is annoying to perform in, but it makes the engineer’s job easier because there’s less room noise to fight.
RT60 Targets by Frequency
Ideally, RT60 should be relatively flat across the frequency spectrum. In reality, most rooms have longer RT60 at low frequencies and shorter at high frequencies due to how sound absorption works—high frequencies damp easily, while bass frequencies persist.
Bass Frequencies (125 Hz–250 Hz)
Untreated rooms often have RT60 of 1.5–3+ seconds at bass frequencies because bass is hard to absorb. Target: 0.4–0.7 seconds in a mixing environment. This is longer than midrange to maintain bass definition without bloat. If bass RT60 is much longer than midrange (e.g., 0.8 sec vs. 0.4 sec at 1000 Hz), the room will sound boomy no matter how good your monitors are.
Midrange (500 Hz–1000 Hz)
This is where speech and most musical fundamentals live. Target the same RT60 as your overall room goal: 0.3–0.5 seconds for mixing, 0.4–0.6 seconds for recording. Midrange RT60 is easiest to control because standard absorption panels work well here.
Treble (2000 Hz–4000 Hz)
High frequencies naturally decay faster because air and soft materials absorb them. Untreated rooms often have RT60 under 0.2 seconds at 4000 Hz while bass is still 0.8+ seconds. In a well-treated room, treble RT60 should stay within 0.1–0.15 seconds of midrange. If it’s much shorter, the room sounds duller and less detailed. If it’s longer (unusual), too much bass energy is being driven by reflected highs.
How to Measure RT60 in Your Space
Quick Method: Balloon Pop or Handclap
The simplest field measurement: pop a balloon or make a sharp handclap in the middle of your room, then use your phone’s voice memo app to record the decay. Listen back and time how long you can hear the sound clearly dropping in volume. This is a rough estimate—not precise, but it gives you a ballpark. Compare it before and after treatment.
White Noise Decay Method
Generate white noise from a speaker at moderate volume (around 85 dB SPL), record the room’s response, then stop the noise and let a sound level meter or decibel-reading app measure how long the decay takes. A handheld SPL meter costs $20–$50 and gives you numbers in dB. You can also use online RT60 calculators that analyze your recorded decay curve.
Professional Measurement
Audio analysis software (Room EQ Wizard, REW, or professional acoustics software) can generate a chirp signal, measure the impulse response, and calculate RT60 at all octave bands. This gives precise data at 125, 250, 500, 1000, 2000, and 4000 Hz. It’s the gold standard but requires more setup and a calibrated measurement microphone (typically $100–$500).
Adjusting RT60 Through Treatment
Too Long (Room Is Too Reverberant)
Add absorption. If RT60 is 0.8 seconds when you target 0.4 seconds, install absorption panels on first-reflection surfaces—side walls, ceiling, rear wall. Prioritize panels at the frequencies where RT60 is longest. If bass is the culprit, add bass traps in corners. Bass traps are more effective than mid-wall panels for low frequencies because corner placement boosts their performance.
Use an absorption calculator to estimate coverage needed. It will ask for room volume, current RT60, target RT60, and absorption coefficients of your chosen materials. The calculator outputs how many square feet of treatment you need.
Too Short (Room Is Dead)
This is less common but happens when you over-treat. If RT60 is 0.15 seconds and you’re aiming for 0.3 seconds, replace some absorption with diffusion or lower-absorption materials. Diffusers scatter reflections without killing them, keeping the room feeling alive while controlling flutter and early reflections. Alternatively, remove some panels or switch from high-NRC foam to lower-NRC fiberglass.
Uneven RT60 Across Frequencies
If bass RT60 is 0.8 seconds while midrange is 0.3 seconds, the problem is unabsorbed bass energy. Standard wall panels don’t address this—you need thick, low-frequency absorbers in corners. Conversely, if treble RT60 is 0.8 seconds (unusual), treble is being over-reflected by hard surfaces or speakers; add high-frequency absorption on the rear wall.
Frequently Asked Questions
Can I have different RT60 values at different frequencies?
Yes, and in fact you always do. The goal is to keep them close—within about 0.1–0.2 seconds across the spectrum. If bass RT60 is 0.6 seconds and midrange is 0.3 seconds, the room will sound boomy and unbalanced. Proper treatment aims to flatten the RT60 curve so decay is similar at all frequencies.
Is 0.2 seconds RT60 too short?
It depends on the use. For podcasting and voiceover, 0.2–0.3 seconds is ideal—short enough to keep speech clear and crisp. For music production and mixing, 0.2 seconds feels dead and boxy. For mastering, 0.3–0.4 seconds is better because you need to hear detail without room coloration. Under 0.1 seconds would be unusually dead.
What RT60 do professional studios use?
Large mixing rooms often target 0.4–0.6 seconds to balance clarity with liveliness. Mastering suites are usually slightly shorter (0.3–0.5 seconds) because precision matters. Recording studios vary: tracking rooms might be 0.5–0.8 seconds to add ambience, while overdub booths might be 0.2–0.3 seconds for dry captures. The variance reflects the fact that different uses want different acoustic signatures.
How much does RT60 improve with basic acoustic treatment?
A typical untreated room has RT60 of 0.8–1.5+ seconds. With 30–50% wall and ceiling coverage using standard panels, you can expect RT60 to drop to 0.4–0.6 seconds (a 40–60% reduction). Full professional treatment can bring it down further. The law of diminishing returns applies: the first 50% of coverage gives 50% improvement; the second 50% of coverage gives only an additional 25% improvement.