Pictures of my Tri-amped Open Baffles

[Poultrygeist]

[Poultrygeist]

[Feanor]

Good work Bill I know yours sound good. They've gone up in price at PE but I was patient and ordered them from China. Here they are mounted atop the OBs.

Looks good!

[Poultrygeist]

After experimenting with different mountings I think I've finally found the one where the Neo 3 planar tweeters sound the best. I settled on this simple lollipop mount with no mounting legs to influence the rear wave.

[Poultrygeist]

[londo1dw]

I've lost the specific thread, but I remember you offering to share your plans for your take on Martin King's H-frame OBs. Of course, your tri-amped version is also of great interest. I'm a newbie on audio review, but I've thoroughly enjoyed following your adventures in the OB world.

[Poultrygeist]

WOW it looks like all the pictures evaporated from this thread???

My Beta/Alpha H-frame OB's have continued to evolve but the basics are unchanged. The H-frames are an open ended cube with all interior dimensions measuring 17 inches. Martin King's is a little larger as he uses an 18 inch woofer rather than the 15 inch Eminence Alpha 15A. His dimensions can be found at his quarter wave website.

The Alpha is mounted in a 17 X 17 inch flat baffle in the exact middle of the cube. The inverted T which rests atop the H-frame is 24 inches high and the width of the H-frame. I used that height as I had a half sheet of MDF on hand. My Beta 12LTA's center is mounted 15 inches from the bottom and 7.5 inches from the side. If I build it again I'll drop it down from 15 to 14 inches.

The tweeter center is 4.5 inches from the corner. I plan to replace the in-baffle super horn tweeter with the B&G Neo 3 planar tweeter which currently sits above the Beta on a lollipop stick mount.

I still use the 2a3 Bottlehead mono block SET to drive the Betas but now use two 300 watt class D plate amps to drive the Alphas ( Yung SD300 on sale at PE for $99 ). The 300 watt plates are way more than I need so the Yung SD200 would work fine.

Plate amps if you don't know are replacement sub amps. I cut a 4 inch pine board in sections to make the frames they rest in and added binding posts on the rear which connect to the H-frames via speaker cables. I show some pictures of them over at AK under the modern gear section.

The Neo 3 tweets are being driven by a Topping T-amp but I plan to try them with a Miniwatt SET to see how they sound.

A major improvement came from moving to an active crossover. I now use a Behringer CX2310 two way to handle the crossover for the Neo tweets and the Beta mids. I discovered that by depressing the 2310's frequency x10 button I went from high to low to high to mid range. The Alphas use the plate amp crossovers which is a better choice. I tried a Behringer 3 way but couldn't get it to sound right so I returned it. The cheaper CX2310 is transparent in my system.

I've received several PM's from very happy AK members who have built this OB. The general comment seems to be "they sound so much more open and alive compared to box speakers". One guy at AK said the "Alphas in the H-frames are the best reproducers of natural sounding bass he's ever heard" and he's heard a lot.

Another great advantage of OBs is the ease in which they can be built. If Poultry, who has never built a birdhouse, can do it anyone can.

The straight cuts can all be done at Home Depot so the only thing left is the driver holes which can be done with a drill and a jig saw but better still with a router and Jasper circle guide.

[Poultrygeist]

I guess there's no reason to post pictures or anything else here anymore.