2-way speaker with best bass

I know all the arguments about how crossovers can screw up loudspeakers, and hence the many inherent advantages of 2-ways over multi-driver designs. But there comes a point where the laws of physics can only be bent so far...

So... what IYO is the 2-way speaker that most successfully plumbs the depths, that provides the best full, but "tight and tuneful", bass, with good pitch definition, without completely messing up the higher registers?

For the moment, let's not worry about how this achievement might affect impedance and sensitivity.
Certainly Brobdingnag has the best bass. Lilliput may offer some astute, refined, defined and well behaved speakers but the greatest among them can ne'er be more than a magnified miniature.
Sonus Faber Extrema and Usher BE-718 were the two best 2-way I have owned when come to bass quality and quantity.
Audio Note AN/E's. Various ways to place which results in various bass response. I prefer the paper cones. To my ears more tunefull. The hemp will probably play louder before breaking up.
These discussions of how low a frequency can be reproduced always lack one important detail...How loud? Earphones, with tiny "cones" can reproduce the lowest frequency, but at a volume so low that they need to be on the ear to be heard. Small loudspeakers can likewise deliver excellent LF performance, but not at a reasonable volume, particularly in view of the human ear's roll-off at low frequency. Large cone drivers can deliver LF at a volume which is realistic, and without the extreme distortion-producing cone excursion typical of small-driver systems trying for the lowest octave.
Eldartford - good point - reasonable SPLs in the bass means large woofers -
large woofers are ill suited to producing midrange - this is why a two way
system ends up as a near-field or life style type trade off. They are the most
common speaker on the planet because they are the "minimum"
necessary to get 60 to 12 Khz in a flat response. Since the 80's two ways
have been delivering ever more prodigious bass but this is at the expense of
quality bass and a quality midrange - it has all become boom boom tizz,
IMHO. And, as a consequence, no wonder some people are enamored by the
midrange magic of single driver speakers!

If one is to ignore home lifestyle and other domestic considerations and go all
out for just quality sound then one is forced to consider three way or four
way (three way + sub) designs, IMHO. However, there is no doubt that a two-
way seems likely to remain the most popular speaker on the planet - so the
question on this thread is an interesting one!

Those who suggest that simply adding a sub will fix the bass issues of a two
way are forgetting that this is NOT true for the majority of ported bass
extended two way designs - if you go this route then you ideally want a
sealed box two way speaker that rolls off at 80 HZ and has its design goal on
the midrange quality rather than shock and awe ( a design that is NOT bass
extended with all the inherent phase & distortion issues and the typical mid
bass bump up to give "impression" of deep bass).