Originally Posted by Erich H
There's really no way to get a legit 99db sensitivity out of midranges that can fit under a waveguide and still keep the height around 11" or less and the width under control.
Just a few ponderings,
The 1099 would be 12.5" tall when laid horizontal using 3/4" MDF. If you used 1/2" baltic birch instead, that would drop it to 12" in height. Now replace the SEOS 10 with a SEOS 8 and that would drop the height another 1.2 inches for a height of 10.8 inches. Replace the 10's with the 8's from the 88 Special to narrow the horizontal cabinet by another 4 inches. You have all that extra space above the 8's and the horn is now narrower than the 5" mids--put a slot/triangle/round vent between the horn flare and the 8's. I'm sure with a slight change to the bezel, it could be made 10.75 inches tall. The point of putting the slot vents above the 8's (or below if you can fit them there) is to remove the extra 1.5" wide slot vents from either side of the 1099.
The 36.25" width of the 1099 drops to 35.75" by using 1/2" BB, drops another 3.7" because of flange width between the Delta 10 and Beta 8 for 32.05 inches then another 3" because of eliminating two 1.5" wide ports off the sides. Roughly 30"W X 10.8"H X XX D for the "898" using a SEOS 8 horn, 5" mids from the 1099 and two 8's from the 88 Special (and Fusion 8 if it comes back)
Figure if 1/2" baltic birch used in the Fusion 8's was good, using the same 1/2" baltic birch for the "898" would also be good. The 1099 center section seales off the air space between the two woofers so no worries about stiffness with proper braces. The HTM 6 uses the SEOS 8 waveguide at 1600Hz so the roughly 1700Hz crossover point for the 1099 makes it not an issue. The "898" can use a mix of existing parts with only the bezel, flatpack and crossover being different. No worries about custom drivers, more inventory of drivers and all that jazz. It won't be a bass monster but the two 8" drivers in my 88 Special work very well as a center--as long as you use subs.
The "898" would be a center that has a face that is 28.5% smaller than the 1099 and only a drop of half to one dB of efficiency. Since it uses the same mids and compression driver as the 1099, it should have very close timbre to the 1099 while being smaller, quite a bit lighter because of 1/2" BB and yet not give up much. Although, generally speaking, your customers don't think of custom drivers much--you sure do!
I pondered "rolling my own "898" because my furiture could not be modified to hold something that wide. I then figured out how to modify the furniture to hold the 88 Special so went in that direction. Still, I don't think many people would complain with the "898" and it would be less expensive as an extra bonus. Sure, baltic birch is expensive but the cost savings on the kit end should cover the increased cost of a 1/2" baltic birch flatpack.
Just a few thoughts on a cold day--an idle mind is the DIY playground". Have a great weekend and looking forward to those Neo coaxials.