Improving MateBook X Pro’s Speakers

Measurements in Stock Form

The MateBook X Pro has some of the best speakers on any ultrabook, but they’re not perfect. As you can see from this graph (the brown line is the frequency response), they sound a bit bright and lack bass. The bass mostly extends to about 200Hz but my desk gave it another resonance down at 135Hz.

The brown line is the frequency response, and the others are the harmonic distortion levels.

You can refer to this graph to adjust your equalizer setting in the Dolby app. You can also right click and download my Room EQ Wizard file to generate an equalizer setting for Equalizer APO.

Audio Drivers

Switching to generic Microsoft audio drivers in Device Manager makes the sound absolutely fecal. This leads me to suspect that basic but apparently necessary processing (such as coordinating between the pairs of tweeters and woofers) occurs in the Realtek drivers provided by Huawei (through Windows Update or otherwise).

Distortion Problem and Possible Fix

The MateBook X Pro’s speakers have a distortion at around 550Hz. Both my unit and another at a Huawei store have this problem, so it’s most likely a design flaw instead of a defective unit. I’ve found the cause to be the bottom of the speaker enclosure vibrating against the laptop’s unibody shell.

To reduce the distortion problem, I removed the foam seal around the speaker drivers. Now, the bottom lid no longer presses the speaker against the unibody.

More importantly, I also put a thin strip of sponge under the speaker to separate the resonating components.

This is the change in frequency response:

Other than a reduction in low treble, the frequency response stays intact. Very fortunately, this mod doesn’t reduce bass.

Correction with Equalizer APO

I used Room EQ Wizard to generate an Equalizer APO config that flattens the frequency response between 200 Hz and 20,000 Hz.

Here comes another problem: Correcting frequency response inevitably eats into volume, of which laptops have not enough to sacrifice. Equalizer APO now has a built-in, always-on limiter, which is generally better than allowing clipping. So, you could just up the preamp, but that means the limiter would kick in to prevent clipping, and all songs with heavy bass beats start to oscillate in volume.

Here’s a solution. Most songs’ dynamic range is dominated by bass, which laptops can’t really produce anyway, so you might as well high-pass it out. With 3 high-pass filters, you can effectively boost the preamp far above 0dB without much dynamic range compression artifacts. Now, everything sounds about as loud as with no correction at all, but with much more accurate frequency response compared to MX Pro in its stock form.

I packed the high-pass and preamp filters into a separate config file that is specifically for high volume listening, so that I can easily turn them all on when and only when I need them.

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