IMO the 19 is the ultimate expression of Altec and fixes the weaknesses of the older models with it's extended highs and lows and improved imaging. All the while retaining the clarity and hair-trigger dynamics big Altecs are noted for.
I'm prejudiced against the 14; the woofer just ain't real Altec to me; it appears, I dunno, lazy. I'd prefer the 414 woofer with it's glorious midrange and put up with less deep bass. This may very well be an irrational view but there it is.
I've read criticisms of the Model 14 lower mid and bass which is often described as being bloated and slow in transients
I have found that generous amounts of dampening behind the speakers and in corner bass traps using OC 703 panels have removed any trace of bloat, and gave the midrange a wonderful, more natural tonality.
Placing the speakers on 1.5" of plywood dollies in order to roll them out of harms way, I accidentally found that this tightened up the bass further.
The Mantaray horn with its dispersion characteristics and Tangerine phase plug does produce nice clean extended highs and really is very nice.
The end result of all the room treatment and placing the speakers on thick plywood dollies is some really terrific sound.
As far as the lf drivers not being "real Altec", contrary to common belief, they where not sourced out to CTS but manufactured in house.
My source for this is a posting (I think on the Altec Lansing Forum) by a former employee at Altec.
If I can find that thread again I could post a link to it.
No the M14's are not M19's but in a smaller space they can acquit themselves quite credibly and not give up too much in the way of detail, tonality and dynamics.
All this being said, had I a larger space, it is a certainly that the m14's would be history and there would be a pair of M19's in their place.
Art