I couldn’t be happier with my Heresy IV’s....unless someone offered me some la Scalas.
Looking at those Altec's, you ARE looking at La Scalas I assume.
The Cornwalls are a great loudspeaker. The woofer crosses to the midrange horn at 700 Hz. Thus the woofer carries a large chunk of the midrange. Remember, middle C is 256 Hz. This means the bass requiring long excursions is going to Doppler distort voice which is very noticeable once you now what to listen for. This makes a subwoofer essential for the best performance. This is true of any speaker that does not have a built in sub driver. You will hear people frequently say that adding a sub "opened up the midrange" of their speakers. The added bass is nice also.