JBL-NOT!! - DIY 4351 Studio Monitor

I am trying to build my own 4351’s.. I need the outer overall measurements and the port size & length. Any help would be appreciated.

Hi Guygella,

Since you said "Any help would be appreciated."

I think i have some of the 4351 information you are looking for. Well, there's one twist its in Japanese language i don't speak, not the easiest one to read either, however numbers remain numbers and that's what you're interested in. I was able to figure out a couple of things like dimensions, but certainly not all there is.

A professional translator would be expensive, see if you have a Japanese friend or neighbor, or better yet find a Japanese girlfriend (lol) and you might be in business! A not too expensive alternative could be to eat in a Japanese restaurant and have someone there do a little translation of important stuff for you in exchange of extra gratuity. Gotta do what you have to do...

The JBL speaker builder material on-hand gives port dimensions for a number of models, not for the 4351 though. However there are some ways to "reverse engineer" such port, not really difficult when having some basic data but it takes a little time... Btw the 4350B seems to use similar port diameter but length may be different.

Let me know here if you're still interested in the data.

I can't post it here but if you send me a Private Message with an e-mail address i could forward the info to you. Regards,

Richard

If you have a 4350 system it would be possible to test your drivers for box tuning and impedance then move to the 4351 and run the same tests. You can measure box volume accurately by closing all the ports and observing the change in resonance of the drivers compared to free air resonance. Both the 4350 and 4351 should have the same result and solid fill or fiberglass can be used to make them.the same.
With the same volume you can approach tuning. Cut just one tube of the 6 to fine tune them.