Category Archives: Audio

HE400i EQ: Back to Basics


After a year of listening to my HE400i with the previous equalizer settings I made, I decided to use a less aggressive version that only corrects the obnoxious treble peaks and compensates for the sub-bass deficiency.

Measurements and Correction

As always, the greatest appreciation goes to Solderdude at Just like last time, the measurements come straight from Solderdude’s home-made measuring rid, which I find exceedingly accurate. Check out his measurement methodology here and join the conversation at the DIYAH forum.

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[Nexus 6P Guide] Install Viper4Android on Nougat

Here’s a guide to successfully install Viper4Android and make it work system-wide on Nexus 6P running Android Nougat (7.0 / 7.1).

Starting from the very beginning:

Flash the Factory Image from Google. The phone will boot after flash.

Turn off the phone and go into bootloader mode. Connect it to the computer.

Execute “fastboot format userdata” on the computer to disable encryption. Continue reading

Nexus 6P Speaker Measurements

The front facing speakers on the Nexus 6P are relatively potent. These measurements were made with the phone standing horizontally, supported by a pillow. The UMIK-1 measurement microphone was about 20cm from the 6P, and pointing perpendicular to the screen.

Please ignore everything below 250Hz! The 6P doesn’t produce enough volume at those low frequencies to be detectable over the noise floor.

Left=red Right=green

Left=red, right=green



Waves NX Impulse Response Analysis

Unlike most other headphone surround sound emulators, Waves NX does a relatively good job at preserving the quality of the original sound while simulating an out-of-your-head soundstage. But let’s see how it actually changes the sound.

I loaded a 192KHz Dirac delta impulse into Adobe Audition and applied Waves NX to it with these settings:

Waves NX Settings 59.5 28.5 60

Sending an impulse on the left channel yields this:

30 59.5 28.5 IR Continue reading

Equalizing HE400i – Take Two (v7.28)

November 2017 Update: I made a revised version here.


Use the files in the Download section below to give your HE400i a neutral frequency response. It sounds good.


My first attempt at developing an equalizer setting to flatten the HiFiMan HE400i‘s frequency response yielded excessively elevated 8KHz and 10KHz regions. This is because I used InnerFidelity‘s measurements. They are consistent among themselves, but the Hammershøi and Møller HRTF curve that I used for frequency response compensation is inappropriate for Tyll Hertsens’s Head Acoustics HMS II.3 head simulator, so the compensated frequency response was a off in the treble.

This time, I asked Solderdude (administrator of DIY Audio Heaven) for his measurements of the HE400i made with his home-made measurement rig. Although Solderdude’s device is not a calibrated HATS, I find his measurements to be very accurate.

Measurements and Correction

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2012 Benz GL Harman Kardon Measurements

These are some frequency response measurements of the 2012 Mercedes-Benz GL-Class’s optional Harman Kardon in-car sound system. While its frequency response is far from neutral, this 12-speaker sound system is quite enjoyable to the ear. The sub-bass boost compensates for the engine noise, and the treble roll-off makes a non-fatiguing sound, which is especially appreciable for long road trips.

Driver Seat


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