Equalizing HE400i the Mathematical Way

Warning: this project is now deprecated in favor of the second revision.

Capture

Measurement: raw uncompensated frequency response by InnerFidelity

2008DF

Target frequency response: an average of 47 subjects’ head-related transfer functions by Dorte Hammershøi and Henrik Møller (recommended as most accurate on Rin Choi’s blog), with 4dB sub-100Hz bass boost for body vibration compensation.

For use with the following equalizers:

APO

  • Equalizer APO in variable band graphic equalizer mode (quasi-parametric: custom frequencies and gains, no Q/bandwidth setting because straight lines are drawn between the set points).

EQuilibrium

  • EQuilibrium, a fantastic high-quality parametric equalizer with support for more bands than you’ll ever need. (Set master gain to -7.7dB or autogain.)
  • Any other parametric equalizer with support for 17 or more bands. (Set preamp/master gain to -7.7dB.)
Q value parametric

Preamp: -7.7 dB
Filter 1: ON PK Fc 102 Hz Gain -2.5 dB Q 2.00
Filter 2: ON PK Fc 142 Hz Gain -2.3 dB Q 2.00
Filter 3: ON PK Fc 252 Hz Gain -4.1 dB Q 1.00
Filter 4: ON PK Fc 505 Hz Gain -2.9 dB Q 1.36
Filter 5: ON PK Fc 963 Hz Gain -5.1 dB Q 1.00
Filter 6: ON PK Fc 2,107 Hz Gain -11.8 dB Q 1.54
Filter 7: ON PK Fc 2,135 Hz Gain 18.1 dB Q 1.00
Filter 8: ON PK Fc 3,350 Hz Gain -6.3 dB Q 2.29
Filter 9: ON PK Fc 4,315 Hz Gain -2.5 dB Q 9.77
Filter 10: ON PK Fc 5,100 Hz Gain -2.2 dB Q 7.00
Filter 11: ON PK Fc 5,773 Hz Gain 1.7 dB Q 5.00
Filter 12: ON PK Fc 6,657 Hz Gain -4.5 dB Q 2.80
Filter 13: ON PK Fc 9,372 Hz Gain -6.6 dB Q 4.07
Filter 14: ON PK Fc 11,420 Hz Gain 4.3 dB Q 4.09
Filter 15: ON PK Fc 13,000 Hz Gain 7.2 dB Q 1.58
Filter 16: ON PK Fc 19,500 Hz Gain -4.6 dB Q 1.20
Filter 17: ON PK Fc 19,988 Hz Gain -0.9 dB Q 6.00

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Bandwidth parametric

Preamp: -7.7 dB

Filter: ON PK Fc 102 Hz Gain -2.5 dB BW Oct 0.714

Filter: ON PK Fc 142 Hz Gain -2.3 dB BW Oct 0.714

Filter: ON PK Fc 252 Hz Gain -4.1 dB BW Oct 1.3885

Filter: ON PK Fc 505 Hz Gain -2.9 dB BW Oct 1.0383

Filter: ON PK Fc 963 Hz Gain -5.1 dB BW Oct 1.3885

Filter: ON PK Fc 2107 Hz Gain -11.8 dB BW Oct 0.9211

Filter: ON PK Fc 2135 Hz Gain 18.1 dB BW Oct 1.3885

Filter: ON PK Fc 3350 Hz Gain -6.3 dB BW Oct 0.6251

Filter: ON PK Fc 4315 Hz Gain -2.5 dB BW Oct 0.1476

Filter: ON PK Fc 5100 Hz Gain -2.2 dB BW Oct 0.2059

Filter: ON PK Fc 5773 Hz Gain 1.7 dB BW Oct 0.2881

Filter: ON PK Fc 6657 Hz Gain -4.5 dB BW Oct 0.5125

Filter: ON PK Fc 9372 Hz Gain -6.6 dB BW Oct 0.3536

Filter: ON PK Fc 11420 Hz Gain 4.3 dB BW Oct 0.3519

Filter: ON PK Fc 13000 Hz Gain 7.2 dB BW Oct 0.8985

Filter: ON PK Fc 19500 Hz Gain -4.6 dB BW Oct 1.1699

Filter: ON PK Fc 19988 Hz Gain -0.9 dB BW Oct 0.2402

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How I calculated the EQ values

Excel

In Excel, I laid a log-scale graph over the HE400i’s frequency response, which in turn is laid over the target frequency response. I modeled points (frequency, volume) on both response curves and subtracted them to get EQ gain values as well as a properly compensated frequency response, which I imported into Room EQ Wizard to calculate parametric EQ settings.

Download the Equalizer APO config file and the Excel spreadsheet here.

2 comments

  1. isn’t the inner fidelity graph for the he400? not the he400i? two distinctly different cans. Maybe it’s inferred because of the 2014 year moniker? I’m totally asking not suggesting. thx!

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