Category Archives: Audio

HE400i EQ Correction using Rtings Data


I found a frequency response measurement of the HE400i that is more accurate than the ones I previously used in my equalizer settings. I discovered a way to extract the graph data from has measurements of lots of headphones, and their methodology is one of the most accurate. So, I imported their data into Room EQ Wizard and created an equalizer profile to correct the frequency response of my HiFiMan HE400i.

Measurements and Correction

I came up with the filters manually. I’m choosing not to boost the troughs or over-correct the treble to prevent side effects that arise when any particular listener’s ears don’t exactly match this graph.

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Improving MateBook X Pro’s Speakers

May 26, 2020 update: MXPro_stock.txt has been updated with better measurements and EQ techniques! Go download it again in the “Frequency Response Correction” section.


The MateBook X Pro has some of the best speakers on any ultrabook. Unlike most laptops, it has 4 speakers instead of 2: there are a pair of up-facing tweeters under the speaker grill and a pair of down-facing woofers on the laptop’s bottom corners. The crisp up-firing tweeters greatly enhance soundstage and imaging. Nevertheless, these speakers are not perfect, and here’s some ways we can improve them.

Analysis in Stock Form

You can refer to this graph to adjust your equalizer setting in the Dolby app, but to get much better sound, read on.

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HE400i EQ: Back to Basics

New version here


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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