Psychoacoustic reference tool — Chromatic (12‑TET), 1/3‑octave, ISO 226, Bark bands, ERB‑rate & bandwidth, Mel, Microtonal (24‑TET).
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12‑TET pitch mapping from ~20 Hz to 20 kHz with note names, exact Hz, and MIDI note numbers.
Useful for tuning, labeling FFT peaks, and quick pitch↔frequency reference.
| Note | MIDI | Frequency (Hz) |
|---|
1/3‑octave filter-bank banding (centers + ±1/6‑oct edges) across ~20 Hz–20 kHz.
Useful for RTA/measurement displays, acoustics reporting, and broad‑stroke EQ.
| Band # | Center (Hz) | Lower (Hz) | Upper (Hz) |
|---|
ISO 226 equal‑loudness contours: SPL vs frequency needed for tones to be perceived as equally loud at a given phon.
Useful for loudness perception intuition and calibration context.
Note: ISO reference frequencies end at 12.5 kHz.
| f (Hz) | α | Lu (dB) | Tf (dB) |
|---|
Bark critical bands (edges, centers, widths) derived from a Zwicker‑style Bark mapping.
Useful for masking/intelligibility reasoning and perceptual audio model intuition.
| Band | z‑range | Low (Hz) | Center (Hz) | High (Hz) | Width (Hz) |
|---|
ERB‑rate is a psychoacoustic frequency scale; ERB bandwidth approximates auditory filter width in Hz.
Useful for perceptual filterbank design, hearing/speech research, and “how wide is the ear’s filter here?” intuition.
| Hz | ERB‑rate | ERB width (Hz) |
|---|
Mel is a perceptual pitch scale that compresses high frequencies.
Commonly used for mel filterbanks and MFCC pipelines in speech/audio ML.
| Hz | Mel |
|---|
24‑TET pitch grid referenced to A4=440 with step index and cents deviation at the cursor.
Useful for microtonal composition/tuning and quantization sanity checks.
| Step | Ref | Frequency (Hz) |
|---|