Many prefer the 2AX its far from being a chevy impala
I've owned 5 pair of AR-3As, 3 pair of AR-2AXs, 6 pair of AR-4Xs, 1 pair of AR-2s and refurbished them all... new caps, polished pots, completely redone cabinets. I know what I'm talking about from first hand experience. The AR-2AX is significantly inferior to the AR-3A to my ears. The AR-3A is one of my favorite vintage speakers, thus the DB5 reference. The AR-2AX is most certainly NOT, thus the Impala reference! I had in mind a 1965 Impala, not an altogether bad automobile, but no DB5.
Here are the specifics to my mind...
The midrange in the AR-2AX is rather a poor one. The domed mid in the AR-3A is excellent in every way.
The tweeters in the two speakers are very similar and are quite good.
The woofer in the AR-2AX is less than ordinary. The woofer in the AR-3/AR-3A is simply outstanding! The two woofers may look alike, but they are light years distant from each other in the quality of their music reproduction.
BTW, the AR-3A is capable of being taken to an all new level of performance by simply replacing the tweeter with a better more modern one. I've found that a nice vintage Dynaudio soft dome tweeter balances the speaker beautifully while also increasing dynamics and detail. However, I would never suggest anyone do such a thing to an AR-2AX because I don't think the speaker is worthy of it... ie. too small a payoff.
Look, there are very good reasons why a nice pair of AR-2AXs sell for roughly $250.00 while a nice pair of AR-3As commonly sell for north of $1000.00. To my ears, they are nothing like "similar" in any way, shape, or form.