Classic studio tape flanging originated by running two synchronized reel-to-reel tape recorders with identical program material while manually pressing a thumb against the rim of one supply reel flange. This gentle friction introduces variable microsecond time delays (typically 0.1 ms to 15 ms). When the delayed tape signal is summed with the direct track, constructive and destructive acoustic wave interference creates a comb-like series of harmonic peaks and phase cancellation notches across the audible audio spectrum.

### Acoustic Comb Filtering Principles In physical audio acoustics, summing an audio waveform with its delayed copy produces fundamental frequency nulls: - **Phase Cancellation Frequency:** Destructive interference occurs at frequencies where delay represents an odd half-wavelength: `f_notch = (2n + 1) / (2 × delay)`. For example, a 1 millisecond delay produces phase nulls at 500 Hz, 1500 Hz, 2500 Hz, and 3500 Hz. - **Harmonic Reinforcement Peaks:** Constructive acoustic reinforcement doubles signal amplitude at integer harmonic multiples: `f_peak = n / delay`. - **Delay Range Distinctions:** Delays below 15 ms produce sweeping spectral coloration (flanging and comb filtering), delays from 15 ms to 35 ms yield acoustic doubling or chorus effects, and delays exceeding 40 ms separate into distinct discrete echoes.

### Calculation Model & Worked Example Rather than performing digital Fourier transform convolution on uncompressed multi-track audio buffers, this utility evaluates a 3-variable comparative index model: - **Primary Dimension / Load (val1):** Base acoustic delay index or track load (default: 100). - **Operating Coefficient (val2):** Modulation depth multiplier or tape velocity index (default: 20). - **Safety / Rate Factor (val3):** Phase damping divisor, guarded against zero division (default: 5).

With default session inputs (delay index val1 = 100, tape velocity val2 = 20, damping divisor val3 = 5): 1. **Acoustic Comb Index:** `(100 × 20) / 5 = 400.00`. 2. **Delay Modulation Root:** `sqrt(100 × 20) = sqrt(2000) ≈ 44.72`. 3. **Signal Summing Efficiency:** `(100 / (100 + 20)) × 100 ≈ 83.33%`.

### Client-Side Computation Privacy All comparative index values and phase scaling formulas execute locally in your web browser. No audio tracks, DAW project files, or acoustic measurements are uploaded to remote servers.