Freddi's Gauss cabinet looks like a good place to start. A Qt of 0.34 works to your advantage so far as keeping cabinet volume as small as possible but you won't be building a sub with this design but rather a good solid woofer. I don't have any practical experience with large Karlson's. What are your desired results or the best case performance characteristics? Moray James.
Thanks for the helpful suggestions. A mutual friend of Moray n' me has built some BR enclosures for some 18" mid-bass (pro) drivers to match to dh1a compression drivers and Celestion mids in Yorkville Synergy horns (under license from Danley). These enclosures are 7 cu. ft. each, so pretty large in a home environment.
Because I know little about the Karlson enclosures I thought I'd ask. As I understand it the Karlsons have very low distortion and are quite efficient, assuming a suitable driver is used. In this case the the drivers are high efficiency (99dB) and the Qts is 0.34.
Should I choose to go this route in the future I think a Karlson might be THE way to implement a HE mid-bass for use with Synergy horns
Freddi has been saying for years how a K can beat many mid bass horns - and I think are a viable alternative to cover the lower end for a synergy. The K has coloration (famous K "W" dip circa 350Hz) and that may or may not be a problem depending on where you cross over.
A 98dB driver will have 98dB down to 60Hz in a K with no baffle step loss (as it has gain).
again thanks very much. Mike is using Dayton PA460-8 drivers. He had intended to port the boxes (6.3 ft³ net volume) that Mike is using. Luckily there is no dip and he is using an active x-over. I suggested running the Synergy horn as one speaker (full range to the 3X's Celestion mids and the EV DH1 compression drivers) and let their natural roll offs take care of the drivers themselves and crossing over to the mid-woofer (Dayton PA460-8). Obviously he is bi amping so no need for passive components.
If looking at the frequency response graphs of each, it seems that there is more than enough overlap to allow good integration between the horns and the mid-bass drivers.
I still think a Karlson would be the way to go. Not sure if there would be any better compact horn for use with those mid-bass drivers that might be domestically acceptable (because we all know WAF is important). Something in the under 4.5 ft³ range or so. Else maybe a "W" or "H" mid-woofer. Further thoughts anybody?