What You Are Learning: Before sound ever hits a microphone preamp or tape machine, the physical geometry and surface absorption of the room shape its tone, stereo image, and decay time ($RT_{60}$). Explore how direct sound ($d_0$), early specular reflections (ITDG $\Delta t_1$), low-frequency standing room modes, and microphone polar patterns interact in 3D space.
🎧 Experiment 1: Comb Filtering
Click START AUDIO, select White Noise, and drag the green Receiver sphere close to a wall to hear hollow phase notches and see $H(f)$ ripples.
🏛️ Experiment 2: Sabine vs. Eyring RT60
Change all 6 surface materials from Poured Concrete to 6" Fiberglass and watch the $RT_{60}$ curve collapse from cathedral boom to anechoic tight.
🎙️ Experiment 3: Polar Pattern Reject
Switch the receiver from Omnidirectional to Figure-8 (Blumlein) and rotate Azimuth so the null rejects strong side-wall reflections.