XPS 15 9560, Realtek drivers cripple the sound

** UPDATE **

So far we seem to have narrowed down the problem to the newest driver (A14) being broken. The current solution is to roll back to an older version (A07), see below for the link.

** END OF UPDATE **

I must say I really like my XPS15, but there's one thing I am struggling with since I got it: the sound quality. I saw a lot of discussion online about the Waves MaxxAudio enhancement software, but I found that even the basic Realtek driver is crippling the sound quite a bit. This can be heard easily when you switch back and forth between the WASAPI driver and the Realtek driver (difference of night and day!).

In order to collect proof (and make sure I am not fooling myself), I made a couple of recordings while playing white noise, and the results show clearly that the Realtek driver is problematic.

Setup

Laptop: Dell XPS15 (Windows 10)
Realtek driver: 6.0.1.8569 (nov '18)
Recording interface: Focusrite Scarlett 2i2
Playback and recording software: Reaper
Stimulus: White noise

WASAPI driver

First, I made a recording by playing the audio through the WASAPI driver, which is a very nice system bypassing the Realtek driver. Since we are playing white noise, we expect a more-or-less flat transfer response when we look at the energy versus frequency. The plot below shows that this is the case: the WASAPI driver plays back the audio uncrippled. Note that the audio rolls off at high frequencies (>20 kHz), but this is due to the Focusrite's anti-aliasing filter and not due to the WASAPI driver.

Realtek driver

Next, I made a recording using the Realtek driver. I made sure MaxxAudio and all other audio enhancements were switched off. Audio through this driver sounds very muffled, with too much low-end. This is clearly reflected in the measurement result:

Realtek + MaxxAudio

Finally, I also performed a measurement using the Realtek driver and MaxxAudio switched on (but with the EQ in the neutral setting, and Maxxbass, Details and Width at the lowest possible settings). The graph shows that MaxxAudio does not make the situation better.

Conclusion

From the above we can conclude that the Realtek driver cripples the audio output quite significantly, even when all audio enhancements are switched off. As an audio expert and enthusiast I think this is unacceptable, and does not reflect the quality standards Dell stands for.

Solution

Possible solutions are, in my opinion:

* Use the WASAPI driver instead of the Realtek one: unfortunately this is only possible in pro-audio software like Reaper; the standard Windows mixer does not support routing through the WASAPI driver. Therefore, you're stuck with the Realtek driver if you want to use Spotify, for example.

* Install the 'Microsoft Generic HD Audio Device' driver: this indeed fixes the sound (and has solved more problems for other people as well in the past). However, this solution is not for me, because the energy management of this driver constantly switches the audio interface on and off, yielding very loud pops through my headphones.

* Install older Realtek drivers:  I tried this, to no avail.

* Let Realtek fix their drivers: I think this is the one and only true solution. So Dell, I really urge you to look into this.

Are there more people experiencing bad sound quality with the Realtek drivers? Do you want a solution as well?