BillFitzmaurice.info

Hey y'all,

I just picked up a well used pair of JBL 4602A wedge monitors for $100. The tweets in both are missing and one had a budget 12" replacement cone. I looked up the discontinued tweets and found the asking price for JBL 2402's are north of $100 each! (Maybe that's why they're gone.)

So, 2 questions:

1) Since I can get an Eminence Beta 12CX for south of $100, would that be a quick and easy way to breath some life in these old pros?

2) Any suggestions on a reasonable replacement for the JBL 2402 that will work with the 3kHz crossover?

Thanks,

Beaux

The beta should work pretty well. I'd strongly suggest the new 2013 tweeter. It's a killer.

LelandCrooks wrote:I'd strongly suggest the new 2013 tweeter. It's a killer.

+1, but not with a 3kHz crossover. OTOH using a 3kHz crossover in a two way is really poor practice, unless the woofer is an eight.

which model is the new tweeter?

How about the APT 50 or ASD 1001? I'm not looking for stellar performance, I'm looking for a budget rebuild.

Bx

Hey Beaux,

If you look at all the JBL specs for the wedges you'll see best response in the original HF driver is from 4K up, but useable from 3K at -10dB. That's probably why the crossover was designed at 3K.

Most of the crossovers in Bill's designs are crossing at 2K.

So, the issue isn't if what you are proposing will work, rather how well it will work.
You don't want a hole in response in the range required for vocal intelligibility, which is exactly what you want in monitors.

The beta 12cx has a higher power handling capability than the original JBL E-120 but the APT50 that would screw into the back of the beta12cx has less power handling capability than the original JBL 2402H HF CD.
The ASD 1001 has (slightly) higher power handling capability than the original 2402H, but is a bolt on transducer, so would need to go on a horn flare. If you still have the flares, that might be an option, but no doubt the bolt pattern will be slightly different.

The APT-80 is a higher power option (about the same as the ASD 1001) than the APT-50 and will screw in the back of the beta 12CX. While response wise it may not be perfect with a 3K crossover it is a better option power handling wise I think.
You would need to remove the HF horn and blank off the HF horn area of the monitor if you went this way.

So, in short, if you have the HF flares, I would go for ASD1001 on them (drill new holes to bolt on if you have to) as this means you don't have to blank out the HF horn, and a slightly cheaper driver option would be the Beta 12a.
If you don't have the HF horns, go the beta12cx and APT-80 route, blanking off the HF horn area.

The crossover was also probably designed on the power handling of the E-120, so I would continue to treat the monitor as having that power handling, rathe than thinking the power handling has gone up with different drivers...

Grant,

Thanks for the input.

Grant Bunter wrote: The APT-80 is a higher power option (about the same as the ASD 1001) than the APT-50 and will screw in the back of the beta 12CX.

From what I found, the APT-80 is just an APT-50 with a horn mount screwed on the front and the APT-150 and -200 have a bigger horns. They all have the same power handling.
http://www.sweetwater.com/store/search. ... &Go=Search

Grant Bunter wrote:The crossover was also probably designed on the power handling of the E-120, so I would continue to treat the monitor as having that power handling, rather than thinking the power handling has gone up with different drivers...

As with most of my projects, it's never as quick/easy/cheap as I first think it will be. Once I decide on which tweet, I'll bite the bullet, do the job right and spend a few more bucks for a 2k crossover.

Beaux

Is this the one?

Yep, that's the one, DJP. Except mine don't look nearly that clean. And the tweeters were missing. And I'm going to pull out the old fiberglass insulation baffling and replace it with egg crate foam mattress padding.

One cab had the original JBL E120 cone. I've dropped a Beta CX in the other cab that had an 80watt replacement speaker and it sounds pretty good. Once the tweets show up and I wire in a new crossover, I'm sure they'll both sound much better. If I can find a deal on another Beta 12CX, I'll build a guitar cab for the old JBL cone.

Beaux

This is just my humble opinion: Gut the interior, remove the crossover and such, cut the round tweeter hole to a 4.25" wide by 4" or 6" tall square, the taller being preferred, if it fits. Install a Beta 12A and a 4 or 6 element melded array and the piezo filters. This should give them a cheap resuscitation, but wider dispersion. Thoughts?

I think the array should be vertical rather than horizontal.

I've used those wedges in the past, and for their size, they weren't bad at all.

If the wedge is being used by one person not moving around much, perhaps a tighter horn pattern would be better than having HF all over the place, especially if there are other open mics nearby.

Bigger holes? Melded arrays? Phhht! That's waaaaaay too much work, especially when I've got Otops I need to get back to.

I'm just going dupe the Simplexx arrangement and screw an ASD 1001 on the back of the Beta 12 CX, plug the hole where the tweeter used to be and be done with it. If I want to get fancy, I might to the effort of finding some black gaffers tape to dress the edges where the black fuzzy carpet stuff has started peeling.

Beaux

SayAgain wrote:Bigger holes? Melded arrays? Phhht! That's waaaaaay too much work, especially when I've got Otops I need to get back to.

I'm just going dupe the Simplexx arrangement and screw an ASD 1001 on the back of the Beta 12 CX, plug the hole where the tweeter used to be and be done with it. If I want to get fancy, I might to the effort of finding some black gaffers tape to dress the edges where the black fuzzy carpet stuff has started peeling. Beaux

Great come back Beaux

Does Gaffa come in some colour other than black?....