View Full Version : Enclosure Size. Can anybody offer advice?

09-11-2005, 12:45 PM
I want to build a single cabinet to house 2 x 15" D140F drivers. I want to use this cab solely for bass guitar.

So far I have looked at the tech dawings for the 5.75 Cu. Ft. enclosure and mocked-up an enclosure using WinISD (beta) software. However, no Thiele-Small parameters exist in the WinISD database for D140Fs. I was hoping to find some on this site but havn't yet.

Am I right in assuming that the D140F and D140E are similar? Can I safely use the paramaters of the E to establish goalposts for an enclosure using D140Fs?

So far I have a 7 cu. Ft. box housing both drivers with 2 x ports @4" dia. 3" in length producing a vent mach of 0.05. The box is tuned to 40Hz.

Can anyone help me 'tailor' these dimensions in order to optimise the efficiency of the drivers for a 2 x 15" bass cabinet?

I'm unsure of the rating of these, could they be 80 or 100 watts? Given the relatively low power handling of these (by todays standards) I would like to end up with a cab which is not too much of a trade-off between SPL and the lower frequencies, perhaps a happy medium between the two will be ideal.

Also, can anyone recommend an additional driver/horn that will be suitable for mid/high-mid and top-end? If appropriate I would obviously like to design the baffle with this in mind and if possible uprate the cab to handle approximately 300 watts (using an active crossover).

Any thoughts, advice, opinions? Your input will be much appreciated but go easy on me guys....I'm relatively new to all this stuff!


09-16-2005, 07:27 PM
I always test my drivers to determine the actual TS parameters before building. It is a PITA but at least you know what your getting. There are testers for around 200 dollars from parts express that do the job, if your budget allows i would invest in one.

09-17-2005, 06:23 AM
Under the circumstances some form of testing for actual parameters may be the only way forward.

As far as I'm aware, the D140Fs are one of only a few loudspeakers that JBL didn't release technical info for :o(

From what I've learned so far the D140F can be damaged quite easily by modern bass equipment so I can't be too careful calculating the box size.

A low 'B' string on a 5 string bass guitar rings at just over 30Hz (IIRC) so some form of notch filter may be a pre-requisite in order to limit movement of the cone and prevent damage to the voice coil?

Thanks for your advice.