Let’s keep this one short. Serious Stereo went hog-wild a while back, and they basically perfected a big, mass-loaded transmission line for Altec Duplex descendants. It’s called the “Serious Stereo Speaker,” and it’s about $14,000 if you pick it up in Montana (a pair will fit in the bed of a pickup).
Compared to the mushy, bloated, lumpy response of my ancient Altec factory enclosures, the tight, tuneful bass our of the Serious Stereo behemoths is just refreshing. They’ve also done some non-trivial crossover work to tame the Deafening Shout that Altec duplexes are known for. Making use of Great Plains Audio’s modern duplex drivers probably helps a great deal as well.
Faced with the room’s uncooperative AC unit, the Serious Stereo guys couldn’t jam their speakers quite far enough up against the wall. The bass performance suffered badly. And, yes, “suffered badly” was obvious. And, yes, “suffered badly” was still infinitely better than what you heard from Altec in the 70s.
Electronics in use while we visited were Serious Stereo’s own 2a3 amps ($15,750 per pair) and Berkeley Alpha DAC. The amps made a strong impression. They’re obviously designed as dancing partners for the speakers, and they danced very well.
I should offer one bit of warning. The amps are finished in an attractively applied paint job. It’s hard to call them anything but striking. The speakers displayed, on the other hand, were finished in Early Chopsaw, looking a bit more suited to a DIY maven’s rumpus room than a decorator’s portfolio. No matter how well assembled, plywood always looks like plywood. I like plywood, so that’s not necessarily a deal breaker for me. You may feel differently.