Here’s my attempt at improving the sound of the speakers. I have a calibrated measurement microphone (miniDSP umik-1) and set the laptop on a table with the mic about a foot back from the palm rest, and about 8 inches off the surface. I created a “semi” anechoic environment by stacking sound absorption panels on the sides, back, and top of the laptop.
I used REW (Room EQ Wizard) to record the frequency sweeps of the both speakers playing together. Based on the measurements, I used the EQ tool in REW to automatically generate corrective EQ. I limited the correction to between 100 Hz and 10 kHz and also applied a low end roll-off starting at 250 Hz. The dark red line is the raw measurement, and the light red line is the “predicted” response after EQ is applied. I did not repeat the measurement after applying the EQ since I created the filters later.
Then I applied the filters in EasyEffects (using pipewire) and set them to autoload the preset when the speakers are playing. NOTE: the leftmost filter at 101 Hz is a low shelf, the rest are “bell”.
This is my first attempt but I think it made a noticeable improvement in the sound. They are much less tinny and sound more natural. I don’t know how much variation in frequency response there is unit to unit, but I’d be curious to see if others think it makes an improvement to their laptop. I will continue to measure and tweak as I have time.
A few notes about the measurement… as you can see the speaker output falls off quickly below 400 Hz which is not surprising given their small size. However I did notice that below 400 Hz is where most of the audible buzzing and rattling came from the case so I essentially chopped off most of the signal below 400 Hz. The rattling is gone but of course when listening to music through the speakers there is no kick drum or bass, but it’s a worthy tradeoff for me.
There is also a rolloff in the high frequency starting around 7 kHz, likely due to them being down firing speakers. I found that boosting the treble to extend the high frequency to 10 kHz helped a lot with making voices sound more intelligible.
I had a big resonance at 450 Hz that I think is really important to tame since it showed up in multiple measurements for me, including using the internal mic, which was also noted by @gracefu.