Own Vandy 4a's. Big difference between a 4 and a 4a, despite being cosmetically identical. The 4a was a bargain priced upgrade of all the drivers ($1800), ~1990. Big sonic differences, so don't waste your time with a 4; only get a 4a.
The 4a is the predecessor to the model 5. Retailed with crossover for $5200. Has the original open back midrange in the 3a signature. Two tweeters, one is a super tweeter that extends response to 40khz.
What sets the 4a apart from any Vandersteen speaker is the subwoofer section. It uses isobarics like the model 5 (dynaudio 30w100 and 30w54 12 inchers), but does not include on board amplification or crossover. This is what makes the speaker great and yet also a pain in the designer's derrier.
Great is that with the right wires (real VanDanHul Magnum), and the right sub amp (Electron Kinetics Eagle 2a or later) this speaker can really unload in the bass with a very clean sound that easily integrates with tube amps on top (top section is 8 ohm easy load.) Never heard 5s do that.
The pain is that only biamping with the perscribed wires and amps seems to have the extra magic. A single amp is a joke. Even Krell lacks something on the subs. Only Eagle 2a+ on subs, not 7's which are not even close in the bass. Eagle 400s, bridged 2s, offer awesome power, but the threat of erasing speaker magnets by buzzing an rca and the doubled noise floor from bridging make it a questionable selection.
What makes the sub section driven correctly so fine versus the model 5?:
1. Dynaudio 12 inch sub drivers are smoking good and no longer sold to general public or manufacturers for new designs. If sold today those drivers would cost over $2000 for the 4.
2. Line level crossover. A pain as it requires more interconnects versus the 5's speakerwire level slave sub, but the very clever may bypass the top section and shrink their coupling caps in their upper amps to achieve the first order roll off. Removes some connections in signal path and allows cheap upgrade of amp caps since their value is greatly reduced to achieve 80hz crossover point. In theory this is a noise/sound floor upgrade over the slave setup where the input to the sub is from another amplifier rather than the preamp directly. One can try to replace the WX4 with a superior unit.
3. Eagle 2a and above have superlative bass and were optimized for even order distortion by the iconoclast designer John Iverson. They really integrate well with the upper section for a fine gestalt and excellent concert hall balance.
What holds back a 4a?:
1. Superior tweeters now available.
2. Slightly older driver versions, but 8" midwoofer may also be Dynaudio!
3. No esoteric crossover parts or battery bias, etc. Quality parts carefully chosen, but not boutique!
4. Can't touch cabinet on a 5a, though they have an interesting nude look, especially if one removes the support rods for the oak top.
5. 3a sig with a couple subs gives a good fight with far superior ultra low bass, but the 4a integrates better and makes it to 24 hz.
The 4a done right should have subtle noise/sound floor advantages over its successors. They can be had for around $1000 these days and Eagle amp and vanden hul wires might be as cheap as $500, but just as scarce as the speakers themselves.
