Ah yes, the 752. Should have been a good speaker, with that high-tech Aerogel woofer and a pretty decent cabinet build.
Sadly, not a patch on its big brother, the 753.
Most obvious problem with mine was a fairly unpleasant and detached top end.
Now, there is actually nothing wrong with the tweeters used in the original 752 and 753, it's just the implementation.
The top end issue with the 752 was completely eradicated by upgrading the HF caps and wiring.
That still left a pleasant but ultimately less than enthralling speaker.
Craig's comments above made me chuckle. Various examples of the original 753 that have come my way have had no resistance, 0.5 ohms, or 1 ohms in series with the tweeter.
Unfortunately for the hapless 753 owners, around 3 ohms is the correct value.
Interestingly, judicious choice of amplification could disguise the imbalance and sound fine.
Bizarrely, partnering the unmodded 753's with a Cyrus 2, connected with Mission's own solid core speaker cable, produced an unlistenable screech.
You have to wonder what was going on at Mission Control.