Hearably EQ listening example - 4 October 2026

Three eight-second WAV files use the same original, synthetic bass-and-melody
loop with high percussion. No Spotify track, speech or third-party recording
is included. Audio and generator are released under CC0 1.0:
https://creativecommons.org/publicdomain/zero/1.0/

Download generate.mjs into an empty directory and run with Node.js 20 or newer:
  node generate.mjs
To verify the published WAVs and measurements without changing them:
  node generate.mjs --check
No npm packages or network access are needed.

Original: no EQ.
Less bass: 62 Hz -2 dB, 125 Hz -2 dB, 250 Hz -1 dB.
Softer treble: 4 kHz -1 dB, 8 kHz -2 dB.
All filters are peaking biquads with Q=1.4. Other bands are flat.
Filter equations: Robert Bristow-Johnson's Audio EQ Cookbook (W3C):
https://www.w3.org/TR/audio-eq-cookbook/

Each output is scaled to -24 dBFS RMS over the entire file before 16-bit PCM
encoding. measurements.json reports the encoded RMS, sample peak, file hash,
filter settings and matching gain. Files are mono, 48 kHz. Center-frequency
sine and inverse-filter checks run before generation or verification.

Equal RMS is not equal perceived loudness or LUFS matching. Listen at a
comfortable device volume and adjust playback level if needed when comparing
tone. Sample peaks do not measure intersample/true peaks or physical output.
The filters illustrate two modest EQ choices. They do not reproduce Hearably's
complete processing chain or certify Spotify/website capture compatibility.
Preference on a synthetic loop does not establish speech clarity or a best
setting for another recording, headphone or listener.