Quick answer: RT60 (how many seconds the echo lasts) is the time it takes for a sound to fade by 60 decibels (dB, the unit for how loud a sound is) after it stops, roughly how long the room "hangs on" to sound. Rooms for speech work best around 0.4–0.6 seconds (classrooms, meeting rooms), restaurants around 0.6–0.8 seconds, and worship spaces a little longer for music. Acoustic panels lower RT60 by soaking up sound.

Key takeaways

  • RT60 = how long sound lingers after it stops.
  • Speech rooms: ~0.4–0.6 s. Classrooms: ~0.6 s or less (ANSI/ASA S12.60).
  • Bigger, harder rooms have longer RT60; panels shorten it.

What does RT60 mean?

Clap once. The sound you hear afterwards dies away. RT60 is how many seconds it takes to fall by 60 decibels, effectively to near silence. Long RT60 = words overlap = less clarity.

What are good RT60 values?

See the table for typical targets. Rooms for speech need a short RT60 so words do not overlap. Rooms for music, such as worship halls, can be a little longer. A tall, hard hall can be several times over these targets before treatment.

Not sure what your room needs? Send us a photo on WhatsApp or request a free quote. We'll tell you how many panels, where they go and the price. See our acoustic panels Singapore and recent projects.

Typical RT60 targets (guide values)

  • Meeting room / office · Typical target: 0.4–0.6 s
  • Classroom · Typical target: ≤ 0.6 s (ANSI/ASA S12.60, typical rooms)
  • Restaurant · Typical target: about 0.6–0.8 s
  • Home cinema / studio · Typical target: about 0.3–0.5 s
  • Worship space · Typical target: longer, depending on size and music
What is RT60? infographic

What affects RT60?

  • Room volume: bigger rooms hold sound longer.
  • Surfaces: hard surfaces reflect; soft ones soak up.
  • Contents and people: furniture and occupants soak up some sound.

Panels add absorption (how much sound gets soaked up), which shortens RT60. How much depends on area and NRC (a score from 0 to 1 for how much sound a panel soaks up). See what is NRC?.

How is RT60 measured?

With a sound level meter or measurement app and a loud impulse (a balloon pop or test signal). For quotes, we can also estimate it from the room size and finishes. Phone apps give a rough idea, which is enough to compare before and after.

What we see on real jobs

You do not need to see an RT60 number to hear the difference. But it's how we size jobs: a hard, tall room has a long RT60 and needs more absorption than a small, furnished one.

Get a straight answer for your room

Send us a photo or a short video of the room on WhatsApp (+65 8930 1905). We'll reply with whether panels are the right fix, how many you need, where they go and the price. If it's really a soundproofing problem, we'll tell you.

WhatsApp us a photo · Request a free quote · See prices

Related reading