PDA

View Full Version : what to do with a pair of D131?



c3conv
03-18-2008, 08:26 PM
HI, I am a newbie when it comes to JBL. I was able to get hold of these Signature series D131. I have fostex driver on tqwt boxes with el 84 tube amps. What suggestions can you give for boxes to use these JBLs. Open baffle is alright with me too. Will they be an upgrade from my fostex? I listen mostly to jazz and classics. thanks in advance.

speakerdave
03-18-2008, 10:11 PM
You don't say what Fostex driver you have (and I'm not familiar with them anyway) but chances are that, for hi fi, the move to the JBL D131 is retrograde.

Here is a pamphlet for the 2130, a later, professional equivalent. It shows a frequency response curve of the driver in a closed 6 cubic foot box:

http://www.lansingheritage.org/html/jbl/specs/pro-comp/2130.htm

And here are the pages of a '70's enclosure construction kit. You will find dimensions and baffle layout for 5 and 8 cu ft boxes for that driver.

http://www.lansingheritage.org/html/jbl/plans/1970s-kit.htm

Or you can use one of today's box design programs.

For open baffle I can't help you; should be an interesting experiment, but I believe the result will be further emphasis on the already-emphasized midrange.

To me owning the driver is matter of nostalgia, as it is with the 075. They are unbelievably efficient, dynamic, impressive. But they are tiring after a while. Back in the day some folks used them for hi fi, though the D130 and D123 were much more common for that. I believe the D131 was targeted to a market for simple, low power PA, SR and MI applications where limited space did not allow the box size the D130 requires, although JBL later recommended the same-sized enclosures for both. It's sound of the fifties all the way-- a time when the mere fact of hi fi was a source of endless fascination and the standards applied for satisfaction were nothing like they are today.

David

c3conv
03-18-2008, 11:35 PM
thanks for the info.

4343
03-20-2008, 10:08 AM
Used a pair of these just the other day as a guitar speaker, just for practicing, a real performance might be too much for them. They had great tone in the Karlsen K-12 cabs. (Plans on the web.)

For hi(gher)-fi I have an EV (GASP!) horn with a Dukane (GASP! again!) driver, (which does have a JBL Ti Diaphram). These make good patio party speakers. They can get loud but are not so untiring that your guests will want to move in.:applaud: And notice the EV logo is properly oriented, even if the horn is not!

I run them with a JBL passive crossover for low levels in the garage and bi-amp them when I need a bit more output outdoors.
When I first got this pair of D-123's, I used them as PA midrange, later they became small floor monitors (with a piezo:o: "super horn" tweeter) The floor box saw use as a guitar speaker occasionally, but not often enough to put an on-off switch on the tweeter. The first time, the guitar player just put some duct tape over it, which says something positive about the durability of the piezo tweeter, if not it's quality as a sound production device...:p