Fun with JBL 1725AP

I'm a big fan of JBL's and their design philosophy of 'live' dynamics and high efficiency, a quality very often found in their PA and monitor loudspeakers.
One particular studio monitor I've always fancied having a play with is the 4430/4435.
The distinctive feature being the Dolly Parton/Butt cheeks 2344 bi-radial horn.
The same horn and 2426h comp driver crops up in the 1725AP pro mid tops from a while ago and on finding pair with original diaphragms that weren't blown(the 2206's were a different story) I got them for a rather good deal.
As with most things JBL everything is over engineered and this substantial/heavy trapezoidal enclosure is from the install range and is covered with what looks like carbon fibre wrap boy racers are fond off!

After sourcing a mint pair of 12" 2206 bass mids-really high quality drivers that have 4" voice coils, high power handling and very low distortion I installed them and awaited the arrival of an 8 pole Neutrik speakon plug-think Land of the Giants speakon.

Knowing they are PA mid tops with passive networks designed for pa coverage I wasn't expecting silky highs(it isn't uncommon to find Radian diaphragms in the 2426 to sweeten them a bit)
I was very pleasantly surprised, the mids in particular are actually very good as is the stereo image-the horn doing its job really well.
They are effortless and have for domestic settings enormous headroom.

I've sweetened the hf slightly via parametric eq-nothing drastic just a gentle notch about 4 kHz and will run them above 80hz with a spare XXL400 sub I've got lying round.

JBL dont mess about when it comes to crossovers;



Cant make my mind up wether they need a bra or underpants;



They are rocking the house at the mo'.

 

I like the idea that a 12" driver is only bass/mid and one needs a sub to go with it !

 

Decorum is restored ;-)

 

They are good down to 50 hz and have the headroom to take quite a bit of LF eq if need be but the sub fills the bottom octave out nicely.
These are now my workroom speakers..they sound huge.

 

Spent the afternoon restoring an old japanese little girl's music box-nothing fancy just cleaning up the lacquer and mechanism but must say the entertainment couldn't have been better, late 70's early 80's disco, Change n Chic etc oh my these things just thrive on it, proper smile on your face stuff.

 

I bet you don't get much work done....

 

The 2344 horn is superb - doesn't sound like a horn at all. If you've got some Radians chuck them in, big difference, all good IMHO.

 

Yes horn sound is totally absent, I also use the Array SAM1 vertical horn and there's not a great deal of difference other than the SAM1 images better. The plan was to eventually build some 4430 clones for grins and having now heard the butt cheeks I may well hunt down some 2235's

 

Hard to find unless you use the right cones in another chassis. But they come up in the states from time to time.

 

Looks that way, about 10 years ago I had 4 of the them- well, 2231a's reconed to 2235a's, that were used in some Westlake TM 1 I was restoring.

 

It has just dawned on me this thread is in the wrong room...

 

Hmm, I've heard lots of good things about the aluminium Radian 1255's so decided to order some.

 

Mylar surround and Aluminium dia vs the JBL diamond titanium/Titanium dia.
£170 later....


Good instructions and FR plot.



Install later in the week.

 

Installing the new diaphragms.

These enclosures are really well made.
There are 2 ports moulded under the horn butt cheeks.




JBL Titanium diaphragm with diamond surround;


Slotted Phase plug;


Radian Aluminium diaphragm with Mylar surround;

 

How do they sound?

I had a little trouble with one of the diaphragms but got it sorted with a bit of patience and replacing the foam inside the driver back cap which had detached and was fouling the diaphragm.
I was underwhelmed at first-the Ti dias are very sharp bright and clear, the Radians were initially mutted in the high mids and a tad on the dull side. After a day or so they've really settled down and sound very civilised with a nice smooth sound signature that doesn't seem forced or over detailed. Happy.

 

Any progress picking a bra or underpants for when the grille is off?

 

G-string?

 

One of one on each? You could stack them vertically and put some nicely contoured bracing in between.... (I'll get my coat...)