JBL 4406 035ti Issues

[daversa]

Hi all,

I recently came across a really clean pair of JBL 4406's on craigslist and it seems like I'm having issues with the tweeters. They sound fine on most music, but with movie dialogue and orchestral pieces I notice a pretty bad fuzz/crackle on the high-end of both speakers. I'm hoping to get a little input on the situation before I go buying new parts.

The tweeters aren't completely blown, it just seems like certain frequencies cause a bad resonance.

If someone could walk me through a troubleshooting process I would really appreciate it!

Thanks,
Dave

Edit: one other note, this rattle is imperceptible at very low volumes.

[BMWCCA]

Both sides the same and it doesn't happen with any other source? I'd say it's not the speakers.

Or:

If these are the non-A versions, perhaps the L-pads could use some cleaning or at least work them full cycle a few times, without a signal through them, and try again.

[daversa]

Both sides the same and it doesn't happen with any other source? I'd say it's not the speakers.

Or:

If these are the non-A versions, perhaps the L-pads could use some cleaning or at least work them full cycle a few times, without a signal through them, and try again.

Thanks for the help! Unfortunately it happens on multiple sources. I've tried working the l-pads quite a few times but it didn't seem to help. I'll try cleaning them tonight to see if that helps. Is it possible that a tweeter could partially fail like this? I always thought it was an all or nothing sort of thing.

[hjames]

Thanks for the help! Unfortunately it happens on multiple sources. I've tried working the l-pads quite a few times but it didn't seem to help. I'll try cleaning them tonight to see if that helps. Is it possible that a tweeter could partially fail like this? I always thought it was an all or nothing sort of thing.

Phil's idea is spot on -
You may have tried with different sources,
but what about trying with a different amplifier?
replace all parts in the chain EXCEPT the speakers and see if the problem goes away.

[grumpy]

failing the quite reasonable electronics-string-substitution line of thought...
might be "crap in the gap", but repairs along those lines
can prove semi-destructive, so eliminating all other likely culprits
first is a healthy path. Ensuring -all- internal connections are solid is another,
usually simple check.

[daversa]

Phil's idea is spot on -
You may have tried with different sources,
but what about trying with a different amplifier?
replace all parts in the chain EXCEPT the speakers and see if the problem goes away.

Yeah, I tried the speakers on a completely separate amplifier and input source that normally drives some ADS l300's (that sound great) and it was still happening. It's definitely the speakers.

[rdgrimes]

My solution would be to grab a 035ti off eBay and see if that fixes one of the speakers. I wouldn't rule out tired crossovers either, but a different tweeter will help you do so. In any case, one can never have too many 035ti sitting around.

[daversa]

My solution would be to grab a 035ti off eBay and see if that fixes one of the speakers. I wouldn't rule out tired crossovers either, but a different tweeter will help you do so. In any case, one can never have too many 035ti sitting around.

If I don't have any luck cleaning the l-pads I'll probably go this route . What's the consensus on the Chinese replicas? Also, I noticed there's some people selling the diaphragm only—is that worth pursuing?

[Jonis]

I recently had a similar problem with L20t's but only on one. Distorted, crackling sound. I changed components with the good one until I narrowed it down to the crossover. Waited for a crossover to come up on eBay and now all is good.

[daversa]

I recently had a similar problem with L20t's but only on one. Distorted, crackling sound. I changed components with the good one until I narrowed it down to the crossover. Waited for a crossover to come up on eBay and now all is good.

Ah, wish I had one good one to do the same!

[rdgrimes]

Its probably safe to say that some previous owner has abused these in one way or another. But I think the easiest way to troubleshoot will be with a tweeter. If it fixes the speaker then the crossover is OK. You could also try removing the tweeter and direct connecting to an amp at LOW power, see if you can duplicate the issue using sine waves or HF sweeps.

[daversa]

Its probably safe to say that some previous owner has abused these in one way or another. But I think the easiest way to troubleshoot will be with a tweeter. If it fixes the speaker then the crossover is OK. You could also try removing the tweeter and direct connecting to an amp at LOW power, see if you can duplicate the issue using sine waves or HF sweeps.

Since this only happens at normal listening volumes (not outrageously loud or anything) is it safe to power it up that loud without a crossover?

[macaroonie]

Free download from LCH , the tone generator lets you create a very slow sweep across the audio spectrum. Either burn a disc that you can use in a CD player or if you can run from your computer you can nudge the frequency till you nail the resonance. This will let you get a better idea where its coming from. If its definatly the tweet remove it from the cab and run it direct wth the tone and continue your investigations. No bass of any merit will be present in the signal so you are OK
03 series tweets mostly have a foam damping pad behind the diaphragm. These are known to rot and can have debris in places you don't want it.
To get in at the foam remove the inner for retaining screws and the faceplate should pull away from the magnet. There are postings on this subject in the event that it sticks. I think someone used a hair drier to warm the magnet , thereby releasing the 'stick '.

Good luck

[BMWCCA]

All the talk of swapping out tweeters has me compelled to offer my normal caution when working with the 035Ti that the terminals and the wire connecting them to the diaphragm are extremely fragile. If you even slightly bend the terminals when removing the Faston connectors you can (likely will) sever the wire on the diaphragm or break its connection to the terminal. You can also pull the terminal right out of the plastic housing since they appear to only be glued in-place.

All of this is possibly repairable if you need to and if you are very careful with soldering tools, but paying attention to the experience of others before attempting disassembly is far more satisfying than squeaking out a repair after screwing one up.

No need to ask me how I learned this.

Again, the cheapest way to acquire spare 035Tis is to buy some donor speakers such as L60T. Even a pair of L20Ts can cost less than a pair of 035Tis, though I would consider it heartlessly cruel to part out a working pair.

[daversa]

All the talk of swapping out tweeters has me compelled to offer my normal caution when working with the 035Ti that the terminals and the wire connecting them to the diaphragm are extremely fragile. If you even slightly bend the terminals when removing the Faston connectors you can (likely will) sever the wire on the diaphragm or break its connection to the terminal. You can also pull the terminal right out of the plastic housing since they appear to only be glued in-place.

All of this is possibly repairable if you need to and if you are very careful with soldering tools, but paying attention to the experience of others before attempting disassembly is far more satisfying than squeaking out a repair after screwing one up.

No need to ask me how I learned this.

Again, the cheapest way to acquire spare 035Tis is to buy some donor speakers such as L60T. Even a pair of L20Ts can cost less than a pair of 035Tis, though I would consider it heartlessly cruel to part out a working pair.

Thanks for the heads-up, I really appreciate it! If I take out the tweeter to test it independently do you think I should just clip the wire instead of trying to pull it off the terminal?