Question 1

What is a good RT60 for a recording studio control room?

Accepted Answer

A recording studio control room should have an RT60 between 0.2 and 0.4 seconds, with the lower end preferred for smaller rooms (under 50 m³). The decay should be uniform across all octave bands from 125 Hz to 4 kHz, without any single band exceeding 120% of the mid-frequency average. The EBU Technical Recommendation R22 specifies 0.3 s ± 0.05 s for reference listening rooms. Low-frequency control is critical: RT60 at 63 Hz and 125 Hz should not exceed 1.5 times the mid-frequency value. Achieving these targets typically requires a combination of broadband absorption (porous absorbers), low-frequency trapping (membrane or Helmholtz resonators), and room geometry optimization. SonaVyx RT60 measurement displays room type targets for comparison.

Question 2

What RT60 should a church or worship space have?

Accepted Answer

Optimal RT60 for a worship space depends on the style of worship. Traditional liturgical worship with pipe organ and congregational singing benefits from longer reverberation: 1.5-3.0 seconds, with 2.0-2.5 seconds being ideal for most churches. Contemporary worship with amplified bands and spoken word needs shorter RT60: 0.8-1.4 seconds. Multi-purpose worship spaces that host both styles often compromise at 1.2-1.8 seconds, sometimes with variable acoustics (curtains, movable panels). Speech intelligibility requires RT60 below about 1.5 seconds in most rooms, so highly reverberant traditional churches often need sound reinforcement systems carefully designed for the space. SonaVyx compares your measured RT60 against targets for different worship styles.

Question 3

What is the ideal RT60 for a classroom?

Accepted Answer

ANSI/ASA S12.60 specifies maximum RT60 of 0.6 seconds for core learning spaces under 283 m² (volume under 566 m³) and 0.7 seconds for larger spaces, measured unoccupied and unfurnished. The UK Building Bulletin 93 specifies 0.6-0.8 seconds depending on room type. In practice, 0.4-0.6 seconds provides good speech intelligibility for both the teacher and students. Rooms with RT60 above 0.8 seconds significantly impair speech recognition, especially for students with hearing impairments, attention difficulties, or non-native language learners. Occupied classrooms typically have RT60 about 0.2 seconds shorter than unoccupied due to absorption by people and furniture. SonaVyx helps verify that classrooms meet these critical standards.

Question 4

What RT60 is appropriate for a concert hall?

Accepted Answer

Concert hall RT60 targets depend on the music genre. Symphony orchestra: 1.8-2.2 seconds (Vienna Musikverein is 2.0 s, Boston Symphony Hall is 1.8 s). Chamber music: 1.4-1.7 seconds. Opera: 1.2-1.5 seconds (needs intelligible vocals plus orchestral richness). Recital halls: 1.0-1.5 seconds. The mid-frequency RT60 (500 Hz to 1 kHz average) is the primary metric. A slight increase at low frequencies (bass ratio of 1.1-1.2) adds warmth without muddiness. High-frequency RT60 naturally decreases due to air absorption, but excessive drop above 2 kHz makes the hall sound dull. World-class halls also target EDT slightly shorter than T30 for clarity with envelopment.

Question 5

What RT60 should a conference room have?

Accepted Answer

Conference rooms need short RT60 for clear speech communication: 0.4-0.7 seconds depending on volume. Small meeting rooms (under 100 m³) should target 0.3-0.5 seconds. Medium conference rooms (100-300 m³) should target 0.5-0.6 seconds. Large boardrooms (over 300 m³) may tolerate 0.6-0.7 seconds. Video conferencing rooms need even shorter RT60 (0.3-0.4 seconds) because microphones pick up more reverberation than human listeners, degrading audio quality for remote participants. Untreated conference rooms often have RT60 of 0.8-1.2 seconds due to hard parallel walls, glass, and tables. Adding ceiling tiles, carpet, and wall panels can reduce RT60 to target. SonaVyx provides before/after comparison to verify treatment effectiveness.

Question 6

Does RT60 change with the number of people in a room?

Accepted Answer

Yes, people are significant absorbers of sound. Each person adds approximately 0.4-0.6 m² Sabins of absorption (depending on clothing). A fully occupied 200-seat auditorium adds 80-120 m² Sabins, which can reduce RT60 by 0.3-0.8 seconds compared to the empty condition. This is why acoustic designers specify RT60 targets for both occupied and unoccupied conditions. Typically, the unoccupied RT60 is 20-40% longer than occupied. Spaces designed for music often set the unoccupied target higher, knowing it will decrease when the audience arrives. For speech-focused venues, you want the unoccupied RT60 to already be near the target because even with fewer people, intelligibility must be maintained. SonaVyx lets you measure both conditions and track the difference.

Question 7

What does it mean if my RT60 varies significantly across octave bands?

Accepted Answer

Significant variation in RT60 across octave bands indicates uneven absorption distribution. Common patterns include: high RT60 at low frequencies (below 250 Hz) with short RT60 at mid/high frequencies, which sounds boomy and unclear. This occurs in rooms with thin carpet and ceiling tiles (good high-frequency absorption) but no bass trapping. The opposite pattern, short low-frequency RT60 with long highs, is rare but occurs in rooms with heavy concrete or masonry and hard, reflective surfaces. Ideally, RT60 should be within ±20% of the mid-frequency average across all bands. A rising bass RT60 up to 1.2 times the mid value adds warmth in music venues. SonaVyx displays octave-band RT60 on a bar chart with target ranges for easy identification of problem bands.

Question 8

What RT60 target should I use for a home theater?

Accepted Answer

Home theaters should target RT60 of 0.3-0.5 seconds for volumes up to 150 m³. The THX reference is approximately 0.3-0.4 seconds, which provides clear dialogue, tight bass, and immersive surround effects without muddiness. The decay should be uniform across 125 Hz to 4 kHz, with particular attention to low-frequency control. Many home theaters suffer from excessive bass RT60 due to parallel walls creating room modes and flutter echoes. Treatment priorities are: first, tame early reflections at the first reflection points on walls and ceiling. Second, add bass trapping in corners. Third, add diffusion on the rear wall. SonaVyx RT60 measurement with the home theater target curve shows exactly which bands need treatment and how much absorption to add.

RT60 Target Values: Recommended Reverberation Time by Room Type

Frequently Asked Questions