Dear n80,
I have two copies of AB, a Canadian (
https://www.discogs.com/U2-Achtung-Baby/release/2393394) and a 2011 20th anniversary US remaster (
https://www.discogs.com/U2-Achtung-Baby/release/3238634). Having listened to both in the last couple of days at both moderate and loud volumes, I can't say that the bass is / was overpowering or a 'muddy wall'; in fact, at certain points I would prefer it stronger. To me the treble on this album seems to be in greater danger of becoming jarring or harsh at higher volumes than the bass does. On 'So Cruel', for instance, Bono seems more forward than the kick drum (which may simply be a matter of imaging, for all I know). Adam Clayton's rolling and propulsive bass lines on tracks like 'Until the End of the World' and 'Ultra Violet', while very firm through my system, aren't unduly alarming or overly forceful. And yes, the bass notes on both 'Zoo Station' and 'Even Better than the Real Thing' are quite distinguishable.
However, my system is very different from yours - an Ayre VX-5 and KX-5, a Metronome CD8-t S and a pair of ProAC Response D30Rs, together with Shunyata cables and a Triton v2. The room's about 24 X 13 X 10 ft., the speakers about 3 ft. from the wall and almost 7.5 feet apart, the listening chair about 8.5 feet from them. I did walk around and even right next to the speakers I did not find the bass overpowering. The D30Rs' downward-firing ports significantly affect the way bass comes across, of course.
I agree with gosta that while U2's albums are still eminently enjoyable with 'inferior' equipment, many nuances and finer aspects of these albums' recording, mixing and mastering only become appreciable with more sensitive and resolving equipment. AB is one album that practically shocked me (in a good way) the first time I managed to listen to it through a good pair of headphones. Perhaps the naughty Mr. Lanois and Mr. Eno's production was such that my current system does not (quite) do justice to this album?
I do hope that you can obtain better results with this CD, or other CDs of this album, in future. I, too, consider it a wonderful and powerful work.