First speaker design

[llung]

Hi Klaus,
FWIW, I wasn't thinking about an isobaric system when I made my 2-1/2 way remark. I made that statement without running any numbers and simply assumed that a 5-1/2 inch woofers in a straight 2-way in a sealed box (original stated preference) wouldn't give much on the low end. The "1/2" way was for the 2nd woofer to reinforce the low-end output only; as is sometimes done to counter the baffle step only at a lower f. Box size permitting of course.

[Klaus Stock]

Hi Lou,

FWIW, I wasn't thinking about an isobaric system when I made my 2-1/2 way remark.

right. I didn't mean to mis-quote you to make it seem that you were talking about an isobaric configuration.

The isoparic configuration has been a "pet project" of me many many years ago, so it naturally came to mind while thinking about designs with superfluous drivers

Back then, I built a prototype, with two 15" woofers in isobaric configuration in a compact vented box. The box was almost a regular cube, with a baffle barely big enough for the driver. The vents were of triangular cross section and placed in the corners of the baffle - 3 vents plus a fourth fake vent, for optical reasons. Like the Titanic, which had 4 funnels, of which one was a dummy.

My collegues ran a few tests, and finally demonstrated that the isobaric system was as loud as two standard systems with the same driver model. Right, according to the theory, this is is impossible. Like the Titanic, which was once operated outside the safe operation area (aka SOAR - in the case of the Titanic, the special alloy of the hull should not be used at very low temperatures, as it catastrophically rip apart when mechnical stress occurs), the drivers were driven past their mechanical limits (thermal power was no issue). They ripped.

PTW, the standard systems which used the same driver model, still work after 20 or so years.

Best regards, Klaus