JBL D123 12'' cabinet size?

[vifa32144]

What would be the minimum box size in cubic feet and port size in inches for the JBL D123 12'' 16 ohm extended range woofer?

[GordonW]

They were spec'd to go in the C36 Viscount cabinet, and that was about the smallest thing I've seen them listed for. It's about the smallest volume I'd use them in, too. Smaller than that, they start to get midbass-boomy.

The C36 cabinet is 2.65 cubic feet, plus-or-minus, and the port length range I came up with that worked the best, was a 4" diameter, 4" to 5" long port. Tunes it to the high-30s, IIRC.

BTW: If you're using it with a SS amp, tune the port to the shorter end of that range, OTOH, if you're using a vintage-type tube amp, make the port to the long end of that range, maybe even longer. Difference in amp damping, makes the woofer work a bit differently...

Regards,
Gordon.

[Harvey Gerst]

As I remember both Ed May and Bill Burton (the designer of the D123) felt that 4 cubic feet was ideal for the D123.