Need help with weird crossover design on JBL KIT-speakers?

[M1k@el]

Hi all

Just aquired a pair of JBL kit speakers which seem to be similar in layout to the L300/4333.

(The enclosure, really well-built)

.. until i took a closer look that is. They utilize the LX13 crossover coupled with 2231A woofer, 2410 midrange, 2312 horn, 2308 lens and 077 tweeter.

(Thought I might as well replace the crappy posts with new ones)

I know that JBL sold kits with the LX13 crossover, and that those kits came with the N8000 add-on in order to use the 077.Problem is, my speakers don't have the N8000. Instead, they have something that looks like a non factory have-a-go crossover for the 077 which consists of 2X 2.2uF caps in series, and that's it!


This is coupled with 2X 22 Ohm resistors for the midrange which actually sit _outside_ the LX13 itself (see pictures), one wired in series with the midrange and one wired across its poles.


The green/yellow and brown wires go to the HF-posts on the LX13, I should add. Furthermore, I've never come across a JBL-kit which has the 2410 horn coupled with the other drivers.

So my questions are:

- Does anybody know if this weird crossover setup for the 077 is a design from JBL? (I've always thought that the N8000 was the way to go when adding a 077 to an LX13)

- What's with the two resistors strapped around the posts of the midrange? Are they supposed to be there? Dosen't the LX13 support the 2410 natively?

- Is this stuff any good? The speakers sound fantastic in every way apart from the bass being a little weak, still very well defined though.

Help would be much appreciated since I've reached a dead end by now and can't find anymore info on the Internet.

Best - Mike

[just4kinks]

Nice find! The cabinets look good.

I think you're on the right track already with the crossover: this is a DIY job, and the proper solution would be something like the n8000.

The resistors form an attenuator for the 2410. The capacitors form a first-order high pass filter for the 2405. UHF frequencies will be played by both drivers. It gets the job done, but I think you would benefit from a real second-order two-way crossover.

[M1k@el]

Nice find! The cabinets look good.

I think you're on the right track already with the crossover: this is a DIY job, and the proper solution would be something like the n8000.

The resistors form an attenuator for the 2410. The capacitors form a first-order high pass filter for the 2405. UHF frequencies will be played by both drivers. It gets the job done, but I think you would benefit from a real second-order two-way crossover.

Thank you for confirming that for me

I just ordered replacement caps & resistors for the DIY-filters so I guess I'll stick to this design, at least for a while.

Would be great if someone could tell me what kit these speakers are since none of the S-XX kits fit the driver-setup in my speakers. And one can wonder why a previous owner swapped whatever crossover was in there for the DIY ones?

[Mr. Widget]

Are your mid horns 2307s or 2312s? I would seriously consider you get 2312s if you don't have them and I'd replace the 2410s with 2420s or LE85s. You would then have all of the correct components for 4333A/L300s. Next follow this thread and you will find the info needed to build some excellent 3133 networks that are an upgraded equivalent for the 4333A/L300.


Widget

[4343]

Those are 2.2uF polarized caps! Wired back to back like that they form a 1.1uF non-polarized cap. I bet you ordered 4 2.2uF non-polar caps? If so, send them back and get 1.1's.

[M1k@el]

Those are 2.2uF polarized caps! Wired back to back like that they form a 1.1uF non-polarized cap. I bet you ordered 4 2.2uF non-polar caps? If so, send them back and get 1.1's.

Yes, I ordered 4X 2.2uF since I didn't find 1.1uF at my local shop. Only 1.0uF, but I guess that difference wouldn't matter that much right?

Why would I be better of using one 1.1 instead?

Are your mid horns 2307s or 2312s? I would seriously consider you get 2312s if you don't have them and I'd replace the 2410s with 2420s or LE85s. You would then have all of the correct components for 4333A/L300s. Next follow this thread and you will find the info needed to build some excellent 3133 networks that are an upgraded equivalent for the 4333A/L300.


Widget

I have the 2312 horns, but as you already read they unfortunately sit on the 2410 and not the 2420. Thank you for the link, I've considered building entirely new crossovers but want to know how much of an improvement upgrading the 077 caps and swapping the terminals will be first

[Mr. Widget]

1 cap is cheaper than two.

I've considered building entirely new crossovers but want to know how much of an improvement upgrading the 077 caps and swapping the terminals will be first

If these changes make a night and day improvement, then something was broken or you will be fooling yourself... the latter seems to happen quite often in audio.


Widget

[M1k@el]

Well, I'm not really expecting that big of an improvement after these mods but at least it will feel good to know that the the wires sit firmly in the posts. My speaker wires almost shorted numerous times after coming loose because of them being to thick for the original posts

Since I don't feel like upgrading the 2410 just yet, would it be a good idea to upgrade the caps in the LX13, or am I just wasting my time and money?

My main concern is whether the LX13 is a design worth upgrading or not. I've understood that people improve even on the original L300/4333 filters. This leads me to believe that the LX13 might be somewhat inferior.

Then again, I LOVE the sound from these speakers just as they are but of course realize that there is room for improvement because of the old components in the filters etc.

[just4kinks]

Have you thought about biamping?

[Mr. Widget]

My main concern is whether the LX13 is a design worth upgrading or not. I've understood that people improve even on the original L300/4333 filters. This leads me to believe that the LX13 might be somewhat inferior.

In my opinion JBL's networks have been their weakest link for most of the company's history with the designs slowly evolving over the years. The current designs are quite good, but going back to the LX series... not so much.

I'd suggest what you have are very nice speakers, with a few updates you can have a pair of exceptional speakers.


Widget

[4343]

Was there any damping material in the cabinets? That might make a noticeable improvement if there wasn't any.

[M1k@el]

Was there any damping material in the cabinets? That might make a noticeable improvement if there wasn't any.

Yes there was, and quite a lot of it as well so that went back in as soon as i finished everything

In my opinion JBL's networks have been their weakest link for most of the company's history with the designs slowly evolving over the years. The current designs are quite good, but going back to the LX series... not so much.

I'd suggest what you have are very nice speakers, with a few updates you can have a pair of exceptional speakers.


Widget

Ok, quess I'll consider upgrading the crossovers with entirely new ones in the future then. Or upgrade to something like the 434X with that nice midbass driver.

Have you thought about biamping?

Nope, I'm quite happy with the gear I have and don't really have the money to invest in another amp right now. But I guess biamping has its benefits!


This is what I've come up with so far, at least the resistors and caps don't hang off the drivers like tumores now.



The bass actually got a bit punchier with added detail and decay, som I'm very happy with that. The treble opened up a bit as well and got more detailed.



Thanks for all your help so far, I've got answers to a lot of questions

[M1k@el]

While I enjoy some aspects of the "new" sound from the tweeters I also experience a very annoying sharpness during "S"-sounds in recordings, for example in vocals or in crash drums. When litsening to some recordings this is simply umbarable!Might this be due to the fact that these new caps let "too much" information pass into the tweeter? I mean, I haven't changed the XO-frequency, just upgraded the caps to better ones. Any suggestions on how to solve it? A small resistor or perhaps increase the uF with another cap in parallell?

[victoriobenatti]

If I were in your place, and taking into account the great quality of these components JBL, I would have it lives and experience a stereo 3-way active crossover. Needs three amplifiers, and a crossover, of course. But I guess you could try, even if borrowed from friends, these components to test.
I have systems multiamp many years, I'm pretty sure will be delighted with the results. It takes a while to get the optimal settings, but when it succeeds, is fantastic.

Victório Benatti

[Ruediger]

While I enjoy some aspects of the "new" sound from the tweeters I also experience a very annoying sharpness during "S"-sounds in recordings, for example in vocals or in crash drums...

The recordings should have been mixed with a deesser, if such s-sounds are annoying. There is nothing reasonable You can do afterwards.

Can You name an example recording?

Ruediger