The A3's with new crossover's have much crisper, clearer highs and midrange when listening to strings, horns or cymbals etc. I could not believe the difference in sound when comparing the two sets of speakers. The A4's have also had the surrounds replaced last spring but they have the original crossovers. I hooked them up to my amp in the A/B configuration so that I could compare the two sets of speakers. All of this in anticipation of stacking them with my A4's to hear what everyone has been talking about. I used the Dayton resistors and Solen 6.2 and 6.8 caps from Parts Express. I finally received my parts yesterday and have now rebuilt the crossover's in the A3's. In other words, if you are measuring across a 1.5 ohm resistor and you get a very high reading, the resistor is most assuredly bad. If there happened to be an inductor in parallel with the resistor, you would get a lower resistance reading than with the resistor alone but you would never get a higher reading (resistors in parallel etc.) This is because any other component in the circuit (except low value inductors) is likely to have greater resistance (or infinite if it caps.) so the meter will still read close to the resistor's value. Oops, I forgot, anytime you measure a low ohmage resistor, even if in circuit, you should get pretty close to the rated resistance if the resistor is good. The real model designation is the "A" for walnuts and "U" for utilities.
LARGE ADVENT SPEAKER SIZE SERIAL NUMBER
The original masonite Advents went up through serial number 299,999 and the New Advent started at 300,000 and went on up through 400, something. The 3 and 4 are just continuations of the serial numbers. The speaker is still "The Advent Loudspeaker" albeit the new version. It has just gotten popular to refer to them that way. A3 and A4 don't designate a model number.