Measured Microphone Harmonics Chamber

Build Nearfield, a responsive microphone-position preview for a voice creator setting up a spoken-word recording. No microphone, audio stream, or live measurement is connected; every reading is a deterministic scenario value. The creator's job is to compare voice distance, understand direct-versus-reflected energy, and settle on a practical demo position before recording.

Do not make a product halo animation behind a microphone ad. Turn the halo into a functional harmonics chamber: a deterministic Canvas pickup field, semantic distance choices for 10 cm, 15 cm, and 30 cm, a measurement ledger, non-color risk labels, and a final position guide. Pair Canvas with a text table describing every distance and its scenario readings.

Use this exact content: NEARFIELD; Find the distance before you record.; Measurement preview · no microphone connected; 10 cm; 15 cm; 30 cm; Test 15 cm voice distance; Direct energy; Reflected energy; Plosive risk; Room tone; -48 dBFS scenario; Recommended demo position; 15 cm from capsule; Aim 10° off axis; Keep pop filter 8 cm from capsule; Balanced direct and reflected energy in this scenario; No audio captured; Replay distance test. Do not add studio-quality claims, noise-removal claims, a real microphone brand, hearing guidance, vocal coaching, live decibel readings, testimonials, or a guarantee of recording quality.

Use chamber charcoal #161a1c, measurement cream #eee9dc, signal cyan #46a5ad, harmonic coral #e06b58, brass #d2aa4b, plum #604a68, and graphite #202526. Pair a wide technical display with a highly legible sans and mono measurements. Use polar rings, angle ticks, energy bands, and one measured off-axis marker only where they encode the pickup scenario. Avoid gradients, glowing product halos, microphone illustrations, wave decorations, fake spectrograms, emoji, SVG/CSS art, and device frames.

Test 15 cm voice distance is the deterministic five-second action. During 0–1.0 seconds 15 cm becomes selected and the chamber clears its prior scenario. During 1.0–2.5 seconds the pickup field contracts to the fixed 15 cm geometry while direct and reflected energy bands resolve. During 2.5–3.8 seconds Plosive risk and -48 dBFS scenario room tone settle with text labels. During 3.8–5.0 seconds Recommended demo position, 15 cm from capsule, 10° off axis, and 8 cm pop-filter spacing lock into the guide. The result must stop in a stable final frame and replay identically.

Support distance-selected, measuring, field-ready, risk-labeled, recommendation-ready, no-audio, unavailable-Canvas, empty-reading, loading, error, visible-focus, reduced-motion, and table-only states. Every distance is a real control, every visual reading has a semantic table row, and the interface repeatedly states that no audio is captured. Announce only measurement and recommendation readiness. Put one data-preview-ready marker on the settled chamber and exactly one data-preview-action marker on Test 15 cm voice distance.

At 960×600, keep the full chamber, distance controls, readings, text table, and final position guide within the first 16:10 viewport. Below 720px, order distance controls, readings table, position guide, then a simplified chamber; retain every unit and risk word at 320px without horizontal scrolling. With prefers-reduced-motion or Save-Data, render the final 15 cm pickup field and complete guide immediately with no pulsing rings.

Return one standalone responsive HTML document with internal CSS and JavaScript. Use no framework, external audio library, microphone permission, Web Audio API, network request, stock asset, placeholder, handmade SVG/CSS illustration, emoji, random waveform, lorem ipsum, or prose outside the product. Include one subtle source-prompt link and label all readings as scenario values.