This simulator follows a pulse field in a box-shaped room after the source is switched off. Set room length, width and height, choose how much surface is treated and how absorbent the treatment is, and compare the ideal logarithmic decay with a measured curve that includes a background noise floor.
• A 3D room with distributed acoustic treatment, a pulse source that switches off, illustrative reflected-energy paths and a measurement microphone. • Sliders for the three room dimensions, treated surface fraction, treatment absorption and the measurement noise floor. • Six readouts: Sabine RT60, equivalent absorption area, ideal decay level, decay plus noise floor, remaining energy fraction and physical decay time. • A decay curve on the Curves & measurements tab, two guided experiments with a verification bench, and Learn & assess lessons and a quiz.
Total surface area is S = 2(LW + LH + WH). Untreated surfaces are assigned an absorption of 0.08 and treated surfaces the chosen coefficient, so the equivalent absorption area is A = S[0.08(1 − q) + αq] where q is the treated fraction. Sabine's reverberation time is T60 = 0.161 V / A, and the ideal level falls linearly in dB as L(t) = −60 t / T60.
A real measurement cannot fall below the background, so the measured curve is Lmeas = 10 log10(10^(L/10) + 10^(Lfloor/10)); raising the floor visibly flattens the tail of the decay.
Sabine's equation assumes a diffuse sound field and works best at modest mean absorption; very strong treatment weakens those assumptions, which the strong-treatment experiment notes. There is no ray-traced impulse response, frequency-band analysis or coupled rooms, the 3D reflections are illustrative, and one animation second equals 0.1 physical seconds.
RT60 is the time it takes the sound level in a room to fall by 60 dB after the source stops. The simulator estimates it with Sabine's formula T60 = 0.161 V / A.
Treatment increases the equivalent absorption area A, which is in the denominator, so RT60 falls. The untreated-room experiment compares the same room with and without treatment.
A measurement includes background noise. The simulator adds the noise floor in power terms, so once the ideal decay drops below that floor, the measured curve stops falling.
It assumes a diffuse field and is strongest at modest average absorption. In heavily treated rooms the assumption weakens, so a faster predicted decay should be treated with caution.