Originally Posted by Erich H
Here's the thing. At 22" tall, there's no room for ports on the front. We'd have to jump up around 25" to get two or three 2" ports nested on the front. That's not too bad because that's about the height needed for the SEOS-12 and a 15" woofer. So box sides could possibly be interchanged. But I think we really need something around 21"-22" tall, so I don't think we can just make all of them 25" tall, even though that would be easier.
No offense intended. I'm genuinely curious. Why do you "think we really need something around 21"-22" tall"? Are you receiving emails from folks asking for that? Did the designers spec this size? Was there a poll with votes favoring this? Is this being driven by CNC cut planning?
Certainly, keeping the height limited and the width as tight as possible so the waveguide and round over barely fit will result in the deepest cabinets for a given size (a good thing, imo)... any thoughts on sealing off the top part of the box where SEOS is mounted so you can have a spot to mount crossover and not have the space behind the waveguide mess with box volume? that should allow taller boxes, still some good depth for each volume requirement size, and allow adequate space for ports.... Others would have to run simulations to see the port velocities for given outputs, but I'm a little scared of only having 2 inch ports if these are intended to play loud.... 4" minimum would be my starting point... I'm having flashes to commercial designs I've had that you could hear the smaller ports chuffing away at any kind of volume.... *shudders*
For the JBL 2206 based designs, JBL recommends a couple options, but only commercially built one size themselves, I believe.... they do a 1.2 cubic foot box tuned to 60 Hz as their design: http://www.jblpro.com/pub/obsolete/4646a.pdf
If it's good enough for them, it's likely good enough for others. The JBl is a shallow woofer relatively speaking... so their 10 3/4" depth would be good to follow.... any internal dimensions would have to be at least 8 inches to allow for the driver depth and their requirement of 3 inches of space behind teh woofer to prevent thermal issues.... the JBL requires porting to get any kind of lower end extension to cross at a reasonable low end to sub or give some hope of bass on its own... so again, taking what they are doing with the 4646a box and adding a sealed compartment on top of it to house the SEOS waveguide would be an ideal size, I would think.... The other options they recommend but didn't commercially build is a bigger box, again ported:
says 57 liters (2 cubes) tuned to 50Hz under their "Typical response and Impedance Curves, Enclosure Volume and Port Tuning" section.
says 57 liters (2 cubes) tuned to 40Hz. 1 port 4" X 7.6" long. this link even gives box dimensions that JBL recommends... I assume they didn't just randomly pull those numbers out of a hat and they are derived based on something as far as being more ideal....
I know you were slammed getting caught up on the group buy orders... but I still want a set of your 2352 horns to play with. Please get me a total including shipping to my email and I'll pay you for them immediately. Please keep pushing the Auto Tech guys to do the mould for the SEOS 24" model.... I want a set of those as soon as they are available... I'm listening to some non-ideal JBL waveguides right now and I'd like better.... especially since the beryllium replacement diaphragms should be out very shortly... I want to hear what they can do on a good waveguide and/or horn....
Initial listening on the SEOS-12 plastic is showing that the Radian 475 CDs sound very, very, very good on it. Much better than the QSC waveguide. Kudos to all involved!
Edited because I can't type "mould"...Edited by hometheaterdoc - 7/20/12 at 9:07am