Michael,

Just make sure there's room behind the driver mount.  My 604E's need about 11" of clearance, perhaps the 904's don't need so much (ceramic magnets?).

Dave

At a .16Qts should be more than a stellar performer. Around 15 cu. ft. Vas. I'd love to hear a pair of Imperials with that 904-8A in them

Hello Michael,  I was not paying good attention.  I have not found a site with the model 610 parameters.

Guys/Gals...
Looking for information on a bass horn with a full range speaker like the Altec Duplex. I have 2 Altec Duplex speakers and have considered making a pair but I can't wrap my head around what happens when the horn unloads and the speaker takes over. The horns in the duplexes kick in around 1500-1600Hz but what I'm talking about is the 15" woofer.

Questions:
1) What frequency does the Imperial with a 15 unload?
2) What does the phase/time alignment look like when the transition occurs?
3) What's the roll of look like when it uploads?

This is a little confusing because I can't picture a smooth transition in this setup. Maybe one of you guys have thought about this too? Thanks, Steve

Steve, I would think the drivers would do pretty well down to somewhere around 80 - 100 hz on their own, so as long as the horn helps out around there I would think it would be fine.  I am not particularly knowledgeable about horn design so perhaps that is a useless point.  As far as the HF I've read recently that the older horns (pre mantaray) unload up around 1700-1800, while the CD horns go lower.

Dave