Originally Posted by JimWilson
I've been intrigued by this design for a while, but James Loudspeaker and Pinnacle are about the only ones actively pursuing it. That's not exactly a ringing endorsement for the design. Other then the lack of efficiency, I'd love to know if it's a viable alternative to the traditional front or down firing options.
Unless you have the drivers close coupled as in face-face, you probably introduce more problems than you solve, and waste a lot of space. For the most part this was of interest back in the day when there was less ability to have a woofer built for a specific need. In most cases you are better off spending 2x the money on a better quality driver. In the end it simply gives you a driver with the same Xmax, 2x the Mms, 2x the motor strength, 1/2 the Vas (2x Cms) and the same Sd. In most cases you are better off using a second driver to increase headroom and apply some EQ rather than the attempt to make the box smaller. If you want a smaller box, look for a driver with 2x the mass and more motor strength.
James uses a 4th order bandpass using a PR in their EMB designs, not an isobaric design unless there are other models you have in mind.