E145 in onken enclosure?

[mantisory]

Hi everyone,
I am currently using JBL E145 drivers in the (much maligned) 4560 cabinet, and while I am pretty happy with it (I use it from ~100 - ~800 HZ) I have always thought that I'd like to try an Onken enclosure for it.
Using the onken calculator at mh-audio.nl, and the JBL published specs for this driver, I end up with the following:

box cutoff frequency (-3dB): 40.41Hz
port length (corrected): 27.76cm
port width: 4cm
Vb: 319.96L
Vb total: 342.17L
SPL: 97.37dB

So, a couple questions:
1) Do these #''s sound correct?
2) How do I arrive at proper box dimensions?
3) Are there generalized plans for building an onken enclosure anywhere?
4) Am I heading down the wrong path?

thanks for any thoughts and help you can give me.
Regards,
Byron

[Lee in Montreal]

Hi Byron. What I retain from the Onken design is how the braced walls are used as ducts. It allows for a stiffer cabinet. That's a great idea. Onken initially used a specific driver in his time (was it an Altec 416B ?). That being said, to me it's just another bass reflex cabinet. So, you can calculate the volume you need for your driver, as well as the porting you need to reach your goal.