— RT60 Calculator - Corporate AV
Conference room speech shell, 144 m3, RT60 0.12 s
Problem. An 8 x 6 x 3 m conference room dressed on every surface - carpet floor, full fabric walls, full acoustic-panel ceiling - needs checking against the speech reverberation target. The question is whether treating every surface actually lands the room where a speech design wants it.
Answer. With 144 m3 of volume, roughly 119 sabins of absorption and a mean absorption of about 0.66, the tool uses the Eyring model and returns RT60 of about 0.12 s. The target band for 144 m3 is 0.50-0.70 s, so withinTarget is false: at 0.12 s the room sits well below the band and is over-damped, not in band.
02 / In depth
How this preset reads — the engineering view.
The geometry gives 180 m2 of total surface across a 144 m3 volume. The floor is 48 m2 of carpet at a 1 kHz coefficient of 0.50 for 24 sabins, the ceiling 48 m2 of acoustic panel at 0.85 for 40.8 sabins, and the walls 84 m2 of fabric at 0.65 for 54.6 sabins - about 119 sabins in total.
Because the mean absorption reaches roughly 0.66, well above the 0.2 point where Sabine loses accuracy, the tool switches to the Eyring form and reports RT60 of about 0.12 s. That is a very dry, deliberately over-damped result.
The 144 m3 volume places the room in the office and classroom band of 0.50-0.70 s. At 0.12 s the figure is below the band, so withinTarget is false - this is reported honestly as too dead for speech, not as a room sitting comfortably in target.
The recommended added absorber is 0 m2. There is nothing to add; if anything the room is over-treated. The lesson is that dressing carpet, full fabric walls and a full panel ceiling all at once overshoots the speech target - a real design would leave some surfaces reflective to land inside 0.50-0.70 s.
What this preset deliberately does not solve
- withinTarget is false because 0.12 s is below the band, not in it.
- Added absorber is 0 m2; this shell is over-treated for speech.
- Single 1 kHz band only; low-frequency behaviour is not modelled.
How this preset differs from its siblings
This preset is the over-damped, fully-treated small room: 144 m3, about 119 sabins, mean absorption 0.66, Eyring model, RT60 0.12 s and below the 0.50-0.70 s band. The auditorium sibling is the opposite failure - a bare hard shell of 1,296 m3 with only about 72 sabins, mean absorption 0.09, Sabine model and RT60 2.9 s above its 1.60-2.20 s band. One shows treating every surface overshoots into dead; the other shows an untreated shell rings too live and needs roughly 45 m2 of absorber added.
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— Acoustic · RT60 · Sabine / Eyring · ISO 3382
The room's reverberation time.
Sabine equation (RT60 = 0.161 × V / A) with 1 kHz absorption coefficients — a single-band brief-stage estimator that switches to the Eyring form once mean absorption passes ᾱ ≈ 0.2, where Sabine over-reads. Production design always runs octave-band (125 Hz – 4 kHz) and validates on-site with an ISO 3382 impulse measurement.
Premium consultation · Office / classroom
0.12 s RT60
Outside target — the office / classroom band sits at 0.50–0.70 s. Total absorption is 119.4 Sabins across 144 m³.
Room volume
144 m³
Office / classroom
Calculated RT60
0.12 s
Outside target
Total absorption
119.4 Sabins
Σ surface × coefficient
Target band
0.50 – 0.70 s
for this volume
Recommended absorber treatment
Within target
no additional absorption recommended
Assumptions driving this recommendation↓ expand
- Floor
- Carpet (heavy) (α = 0.5)
- Walls
- Fabric upholstery / drapes (α = 0.65)
- Ceiling
- 50 mm fabric-wrapped panel (α = 0.85)
- Method
- Eyring equation (mean α 0.66 > 0.2), 1 kHz single-band
- Measurement standard
- ISO 3382 impulse measurement (on-site validation)
- Production model
- Octave-band 125 Hz – 4 kHz · EASE / Treble
- Panel α
- 0.85 (premium 50 mm fabric-wrapped)
- Dedicated cinema rooms
- ≈ 0.40 – 0.70 s target (SMPTE / Dolby guidance) — see Cinema Sizer
Engineering caveats
- High-absorption room (mean α ≈ 0.66) — the Eyring form is used because plain Sabine over-estimates RT60 above ᾱ ≈ 0.2. Air absorption is still omitted in this single-band estimate.
- RT60 below target — room may sound dead. Reduce absorption or add diffusion to recover energy.
Operationally sensible ecosystem
Brands grouped by engineering role — not random logos.
Loudspeakers
LCR / surround / overhead arrays
- KEF ReferenceAudiophile-grade home cinema
- JBL SynthesisPro-cinema lineage for residential
- Sonance ReferenceArchitectural reference series
Amplification
Multi-channel + multi-room
- Crown DCi NetworkTouring-grade install amp
- Lab.gruppen ECompact multi-channel install
AV distribution
Matrix + AV-over-IP + endpoints
- Crestron DM NVXAV-over-IP 4K60
- Crestron DM 8K8K HDBaseT matrix
The Sabine / Eyring model is a first-order estimator — a single 1 kHz coefficient does not capture low-frequency modal behaviour or high-frequency air absorption. Production design always runs octave-band (125 Hz – 4 kHz) modelling in EASE / Treble and validates on-site with a calibration microphone + impulse measurement per ISO 3382 before committing specification. Dedicated cinema / mastering rooms follow much lower, tighter reverberation targets (≈ 0.4 – 0.7 s per SMPTE / Dolby guidance) — size those with the Cinema Sizer brief, not this speech-band estimator.
A planning link that reopens this exact configuration — not a quote.
Next step
Take this acoustic target to the AV desk.
This Sabine estimate is an indicative planning figure, not a final design. A short brief lets us run octave-band modelling and validate on-site with an impulse measurement.
· Other presets for rt60 acoustic calculator
· Next
Brief us on the project — with this configuration.
Presets are a typology starting point. The brief wizard captures the room geometry, programme and constraints we need to translate this configuration into a real design.