Some AN models are ported, some are sealed.
IME, there is really no substitute for the acoustic suspension sound in a vented box. Some bass-reflex and transmission-line speakers can play as deep but lack the speed and texture. Open baffles excel at texture but can’t dig very deep. The advantage of bass-reflex is reasonable efficiency with decent extension. AS designs tend to be power hogs but excel in bass quality.
Old models like the Large Advents can match and even surpass some modern designs in many regards. Unfortunately, I find they sound great until they suddenly don’t. They suck up gobs of power and there’s a very sharp transition from clean sound to ugly distortion. Playing them at loud levels can heat up the motors quickly and lower the threshold further. This is why I don’t use my NLAs above moderate SPLs, however, played within their limits they can teach modern designs a thing or two.
The Gershman Acoustics AS designs are intriguing, though I’m suspicious of their claimed sensitivity:
http://www.gershmanacoustics.com/gershman_speaker_modles.html Most ATCs are acoustic suspension.
In the budget realm there's NHT.
