Don’t be fooled by the Harman Kardon name, it’s the same system and components they use in the Enyaq and Audi e-Tron. The subwoofer is almost inaudible the way it’s installed, it’s a cheap Chinese speaker in a plastic box buried in the boot.
For details see here, https://forum.whichmobilitycar.co.uk/forums/topic/update-on-subwoofer-sound-system-quality/
Please excuse spelling/typos. Apart from being a clot it turns out I had one on my cerebellum that's now causing various problems!