These gigantic Monets followed me home when I picked up some vintage Knight speakers for my Econowave build. The guy was moving and his trailer was full. He begged me to take them. Aztec was a local company here in Denver, and not well-known. These guys have been hanging out in the basement for a few years and I just dug them out to give them a listen. But when I removed the grill - empty.
If I rebuilt them, then I'd want to do justice to the awesome cabinetry. Interior dimensions are 11.5 x 24 x 33. I'd probably build them, keep them a little while, then sell because I don't have a room big enough. Anyone have any ideas? 4pi?
I've been searching through AK threads. Consensus is that the drivers are CTS, so same as Magnavox. I have a 15" 4ohm but not sure what the Monet uses. My 8" mids seem original and are isolated in a cardboard tube (see pic). There are 3 x 4.5" tweeters!? Maybe this is some sort of impedance matching thing. The crossover is pretty simple. I see an air core inductor, a cap, and a resistor.
I see a guy on the AK forums who lives in Denver and has a pair. I'll reach out to him and see if he can provide some info on the parts I'd have to get. I found and attached a picture of how they should look.
Here is an add that says special design woofer and advanced crossover. I pulled off some more mattress, I mean, insulation and found more components. Looks like at least 3 more each of resistors, caps, and inductors. Curious.
But I must admit that I would advise against using this cabinet for a four Pi loudspeaker build. I'm concerned about the quality of the midrange in that cabinet. Internal standing waves might cause problems.
The original design had a midrange driver in its own internal cabinet. The main cabinet was energized only with bass frequencies from the woofer.
In a four Pi loudspeaker, the midwoofer energizes the cabinet with bass and midrange frequencies, but the layout - the positions of the driver and the port in relation to the internal surfaces - as well as the positions of the damping material mitigate internal standing waves in the midrange.
If you decide to give it a try anyway, please perform acoustic measurements and pay close attention to the 100-300Hz range.
I would look for a woofer that will work well in that size box. The vent can be changed, so that doesn't need to be seen as a constant but you might be able to find a woofer that works well with that Helmholtz frequency. So calculate the Helmholtz frequency from the box volume and vent dimensions to know what you have there too. Might not even have to change out the port.
You have a fairly large assortment of brands to choose from. I'd probably stick with Eminence or JBL since I'm most familiar with them and I think I could find something that worked in the cabinet. But there are other good brands to choose from too.
The midrange driver won't be hard to source. There are plenty of good midranges of that size. The internal midrange box volume won't mater too much - probably - but do check to make sure the driver you choose works in a sealed cabinet of whatever size that midrange box is. You don't want it to be underdamped. That's really all you need to watch out for there.
Then pick some tweeters. Might be fun to replace 'em with a line of ribbons.
Make sure all your drivers are around the same sensitivity so you don't have a lot of level matching to do in the crossover.
That's too bad if they can't be refurbed as survivors but good on you for even investigating it and not directly abandoning the notion.
If it shakes-out that way, here are my ideas:
1) Beg Wayne for 3-pi thermionic design. Do quickie qtr-wave sims using ewave woofer data. If no showstoppers, whack new baffle to put driver and port where he had them. Stick ewave guts in new baffle. Don't push a bunch of watts but just test-listen (and see how much "bigger" your ewave can sound). Worst case, put your ewave guts back where they were, out one pair of baffle's work but prepped for re-baffling.
2) Beg Wayne for ancient 4-pi thermionic design Obtain remaining parts and make new baffles.
3) Lots of other stuff...depending on what you want. 5+ ft3 is a nice cab to have. And it's built Well I really like those cabs. Heck--I'll do the sims if somebody tells me where the old designs had driver and port relative to overall cab dims (is that a dc300?).
Thanks for sharing the great stuff. Good luck and keep us posted.