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

Hi all

Just aquired a pair of JBL kit speakers which seem to be similar in layout to the L300/4333.http://img849.imageshack.us/img849/3765/dsc02815g.jpg

(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.http://img690.imageshack.us/img690/7775/dsc02820h.jpghttp://img842.imageshack.us/img842/4606/dsc02814cm.jpg

(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!
http://img832.imageshack.us/img832/6610/dsc02816cu.jpg

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.
http://img716.imageshack.us/img716/1197/dsc02817mi.jpg

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

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.

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Originally Posted by 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.

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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?

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

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.

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Originally Posted by 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.

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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?

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Originally Posted by 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

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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 :)

1 cap is cheaper than two.

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Originally Posted by M1k@el

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 :)

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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

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. :)

Have you thought about biamping?

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Originally Posted by M1k@el

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.

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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

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

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Originally Posted by 4343

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

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

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Originally Posted by Mr. Widget

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

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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.

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Originally Posted by just4kinks

Have you thought about biamping?

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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.

http://img854.imageshack.us/img854/35/dsc02821n.jpg

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.

http://img254.imageshack.us/img254/8741/dsc02822zw.jpg

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

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?

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

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Originally Posted by 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...

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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

Quote:

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Originally Posted by 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?

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Yes ( here's one ) !

http://img854.imageshack.us/img854/35/dsc02821n.jpg

- Those two caps are perfectly setup to "DC bias" .

- ( IME ) the presence of DC within a cap can help reduce ( and sometimes, even eliminate ) inexplicable sources of "newly-found" sibilance .

- An explanation of sorts ; a cap holding a charge of DC voltage becomes much less "self-resonant" when it's asked to pass AC signals.
- These " high-Q resonances" are heard when they get triggered by the appropriate ( frequency dependent ) signal .
- This ( statement, if accepted ) can help explain the ( not-so-often ) reported phenomena of an observed, "capacitor break-in period" .
- This also assumes that one will accept the statement that subjecting a cap to a significant AC load, will have the net effect of the capacitor acquiring a residual polarization ( ie; some DC offset where the cap never fully returns to "zero" / which is a "memory effect" of sorts / and you can blame gravity if you must "blame" something for this "asymmetrical" behavior in real world circuits ) .

- To implement; ( with the speaker un-plugged from the driving amplifier and the tweeter disconnected from those 2 caps ) add 1.5 volts dc ( obtained from a AA battery ) to the central junction of the 2.2 caps by applying the "+" voltage to the junction of the two caps ( the "-" side of the battery is connected to the minus side of the crossover network ) .
- Remove battery ( after 24 hours ) and allow the 2 caps to continue holding/storing the dc charge .
- Reconnect the speakers, as well as the network and get back to listening .

- If this seems like too much voodoo for you to accept / well, simply ignore this post ( keeping in mind that it also took quite a while to prove the world wasn't flat ) .

cheers :)

BTW; I (obviously) disagree with that part of Ruediger's assessment that there's nothing to be done .

DC bias can be applied to the center junction of your two caps in series through a high value resistor, at least 1.5 Mohm, from a 9V battery the way JBL does.

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4343

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Earl K

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That's something that I'll definitely look further into. If one can improve the sound just by applying a voltage over the caps that's a great solution!

Thanks :)

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victoriobenatti

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I feel like this is something I'll experiment with in the future since I study and don't really have the money (nor the time) to play around with different amps right now :)

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Ruediger

Can You name an example recording?

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Yes, every singe one of them! But just to give you some examples, Painkiller (Judas Priset), A momentary lapse of reason (Pink Floyd) and strangely every single record by Dire Straits! This leads me to believe that there is indeed something that can be done about those over-emphasised S-noises. Remember, I didn't experience the noises with the old caps :)

(Although I must agree with you that there are some recordings which are just BADLY mastered, I for one can not understand why so many people regard tracks by Katie Melua as audiophile-grade. According to me they are some of the most badly mastered tracks out there, blurry instruments which are barely audible coupled with moddy bass which makes me wonder if the recordings were done in a cave(?) But the most annoying thing is by far her over-reverbed voice which yield those S-sounds making every single track umbarable.)

But back to topic :)

I've done some research and concluded that the best thing to do right now is to build a new pair of N8000 networks. After all, they are very simple in their design and should therefore not be too expensice in parts.

http://www.jblproservice.com/pdf/Net...06 Network.pdf

The biggest advantage with building these will (I think) be that they attenuate the 2410 whist also taking care of the 077, I hope that this will make the crossover between them much smoother. With my current setup, the 2410 is not crossed over at all at high frequencies since it only operates off the LX13. This can't be good if there is a 077 connected as well, right?

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Originally Posted by M1k@el

...and strangely every single record by Dire Straits! This leads me to believe that there is indeed something that can be done about those over-emphasised S-noises. Remember, I didn't experience the noises with the old caps :)

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It seems simple to me, you need a proper crossover.


Widget

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Originally Posted by Mr. Widget

It seems simple to me, you need a proper crossover.Widget

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Yep, and they're on their way home to me now :)

Ok so thought I'll make an update on my progress :)

I've gone one better than my previous filters and have just finished my N8000 clones. Only problem is that the L-pad is only accessible by taking out the bass reflex tube. No big worry though since I've dialed the in 077's the way I like them by now.

http://img689.imageshack.us/img689/1162/dsc02836n.jpg

The harsh and sharp sound is COMPLETELY gone now! The speakers sound much more coherent and I simply love the sound now.

Great news!

I hope you enjoy them for long time... or at least until the upgrade bug bites. :D


Widget

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Originally Posted by Mr. Widget

Great news!

I hope you enjoy them for long time... or at least until the upgrade bug bites. :D


Widget

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I guess I get bit by the bug quite often to be honest :D

I do experience some distortion from the woofers when playing very deep bass, and to be honest I feel that the speakers are a little down on bass in general. Can this be due to demagnetization of the Alnico magnet? I just discovered that the woofers have actually been reconed by a previous owner, thus converted to the 2235(?):s.

AFAIK, there is a place in the US which specialises in remagnetizing speakers. Maybe I should contact them and send the woofers on a trip across the pond to breathe new life into them :)

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Originally Posted by M1k@el

I feel that the speakers are a little down on bass in general. Can this be due to demagnetization of the Alnico magnet? I just discovered that the woofers have actually been reconed by a previous owner, thus converted to the 2235(?):s.

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I would confirm the cabinet size and tuning first... It is possible that mags need charging, but it is also possible the woofers don't have their mass rings or that you don't like 2235 woofers.


Widget

Quote:

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Originally Posted by Mr. Widget

I would confirm the cabinet size and tuning first... It is possible that mags need charging, but it is also possible the woofers don't have their mass rings or that you don't like 2235 woofers.


Widget

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How do I confirm whether they have mass rings or not? That's something I've never thought of.

I played a Hiphop track with very deep bass just to hear how the woofers responded, I must say I was a bit disappointed. The fast and dry bass become thin, farty and slow. In other words, all the opposite of what JBL-bass should be :(

.. and added to that came some distortion as well. It seems as though my woofers simply can't handle that type off deep bass.

EDIT:

Did some searching and found that the 2235H have the mass ring installed on top of the voicecoil and that it should weigh 35 grams, let's just hope that my reconed ones have them as well!