Quiet Here. What Happens One Seat Away?

Can a setting that makes one point quiet do the same one seat away? We model two synchronized sound sources, select a secondary phase using point A only, then keep the settings fixed and move a passive probe to B and C. The device artwork is symbolic; this is a calculated free-field experiment, not a microphone recording or a noise-cancelling product demonstration. At 400 Hz, we test 360 settings (0–359 degrees, one-degree steps). The selected phase is 60 degrees. Relative to the primary-only pressure amplitude at EACH point, the results are A: 0.0061061x (-44.28 dB), B: 1.3235033x (+2.43 dB), C: 0.6942867x (-3.17 dB). A is small, not zero. These are pressure-amplitude ratios, not perceived loudness or total room energy. Quiet at A does not generally force louder sound at B. The connected sampled -10 dB interval through A spans 0.295 model metres along x and 0.145 along y. This illustrative threshold is not a hearing-protection standard, and two sampled line intervals are not a protective dome. After a reviewed style sample, we locked the source code, geometry, gain and phase, then evaluated the prelisted 250, 500, 750 and 1000 Hz conditions. Each retains source-only, old locked-phase and explicitly retuned-phase results. At 1000 Hz, the old phase gives an A ratio of 1.9999; retuning at A gives 0.0022, while B and C remain above their own primary-only baselines. All twelve deterministic policy conditions remain in the ledger; they are not independent human participants or real-room success rates. Model: coherent monochromatic spherical monopoles in an unbounded 3-D free field, shown on one plane. Source 1=(-2,1.5), source 2=(-0.5,0), A=(0,0), B=(0,0.6), C=(0.6,0); coordinates in model metres, propagation speed 343 m/s, secondary coefficient 0.20. Pressure decays as 1/r. Radius 0.15 around each source is invalid/excluded, shown grey rather than quiet. No walls, floor, reflections, people, furniture, directivity, controller hardware, room-energy calculation or calibrated SPL. Audio: 400 Hz calculated signals at stationary points; primary and secondary are already summed into a single mono signal. Stereo playback duplicates that signal, not one source per ear. All six demos use ONE shared gain, 3-second segments and 50 ms fades. No per-clip normalization or compression. Music is absent during comparisons and probe moves. Wave motion is slowed; tone pitch is not. Keep a comfortable volume; do not turn it up to hear the small A signal. This video cannot cancel sound in your room. Digital PCM/AAC checks were completed; subjective listening and real-device measurements were not performed. Chapters 00:00 Quiet here? 00:14 Same sources, new phase 00:36 Choose using A only 01:02 Move the probe to B 01:40 Same distance, another direction 02:11 Pressure is not amplitude 02:47 How far does quiet reach? 03:25 A separate level test 03:50 Lock before a different tone 04:14 New frequencies, then retune 04:54 One calculated point signal 05:23 Quiet where? Sources / context (no source media reused) COMSOL monopole source documentation: https://doc.comsol.com/6.4/doc/com.co... Penn State / Daniel A. Russell, simple sound sources: https://www.acs.psu.edu/drussell/Demo... Penn State, wave superposition: https://www.acs.psu.edu/drussell/Demo... Elliott & Cheer (2015), spatial control background, not this model: https://eprints.soton.ac.uk/375708/ Production: HomiSoft original code-based simulation, charts, animation and synthesized tones/music, with AI-generated symbolic device artwork. No sampled commercial music, voice imitation, or narration. This is not a first-ever claim, installation advice, medical guidance, or proof of real noise-cancellation performance. CHANGE ONE NUMBER · by HomiSoft