I have listened to that speaker and it's all about the "line array experience." I have an intention to build a "similar" speaker, but not a clone. I have built a couple of NSB 16 speaker arrays with either Onkyo or PT-2's. They are running off gainclones ~ very nicely I might add. Friends bring over "favorite" CD's to really listen to the recording.

I posted a similar question several months ago and would LOVE TO HEAR JIM GRIFFIN opine on the McIntosh design. His paper is one of the few technical resources on arrays. However, I am unable to fully integrate his information especially regarding a double line of 4" speakers.

The new design will use 34 NSB's and 7 PT-2's. I will drive the pair using a 4-channel Aleph and MOX active crossovers. Bases will include my present Tuba 18's running off a plate amp. I am willing to take the Pepsi challenge with an NSB clone against the 29's.

Wiring? Balanced or tapered? My original thought is tapered. That's how I came up with the odd number of 34 drivers. Now all I have to do is find that piece of scrap paper! My personal opinion is that I can't hear much difference

The 29's are using a 4" driver with a long line of 1" tweeters. I don't think the 1" tweeters really give you the sound of the ribbons and they are a pain in the ass to wire. I wouldn't do the 1" line again even if they were free... too much work. As for the M-T-M horizontal arrangement of the Mac's, I think there are real technical advantages (less lobing) to the MM-T arangement. One of the design challenges will be to reinforce the baffle with strong backs if they are built with MDF. This will be especially true with a second line of woofers. The structure of the baffle will be pretty weak without a little something in the back. McIntosh uses an extruded aluminum enclosure (not sure about the baffle???) and that might be a reasonable solution. It would be quite possible to job out the baffles for laser cutting, right down to the mounting holes that could be tapped later. One need only to supply the DXF file and pick up the parts the next day. You would also have the opportunity to form the sides in a nice radius (for some BSC). One would simply need a decent plan for dampening the baffles. Epoxy and cement board? That would be pretty dead.

McIntosh is a boxed speaker, my intention is to build an open baffle. Even with a box, the 3" and 4" speaker choices are petering out at 150-200Hz, so you need something low. The Tuba's are VERY tight and the 18's are a decent match for the arrays. The other big question is the baffle step. I don't think that I can sell a 30" baffle to the little Mrs. ~ she's a good earner and I would like to keep her around.

Anyway, the boat went in the water yesterday and I must go to the shop and fabricate spinnaker cranes for the mast. Sailing season has started and (other than the mess in the den) DIY audio season is soon in a 6-8 month moratorium.

• 29's