4350 Crossover Q's

[Audionutz]

G'day all from down here in Oz.

I have a pair of 4350's and wondered if the knowledgeable souls that inhabit this board would assist .....

I've owned them now for some months - powered by Crown D150 on bass and a pair of Marantz MA-24 30 wpc Class A Monoblocks on the top ends.

Basically, in a fit of exuberance over the weekend and fuelled by a gathering of like minded Audio mates, we tried placing them vertically. Didnt work to my satisfaction, either with tweeters inside or outside on the baffles.

Anyway, having gently lowered them back into a more dignified horizontal position last night, I now find I have an imbalance with the speakers.

Center image is shifted noticeably to one side. Have changed amps, connections, all wiring and power supplies, reveresed amps, preamps etc etc . I keep getting back to the speakers themselves. Now, the other noticeable thing is that the attenuator controls on both speakers seem to have far less effect than previously, when I adjust them. This leads me to wonder if the crossover has failed in some way on one, or both ?

If my conclusion is correct and the problem lies within the crossover, I now have the question as to whether to repair, rebuild to standard, or upgrade completely ? I am determined to maintain outward cosmetics, so no cutting or enlarging of holes.

I'd like to know my options before diving into this and also, what sort of improvements to expect with the varuious choices.

All comments, opinions or ideas greatfully considered !

Cheers

'Nutz

[boputnam]

I have a pair of 4350's and ...Basically, in a fit of exuberance over the weekend and fuelled by a gathering of like minded Audio mates, we tried placing them vertically. Didnt work to my satisfaction, either with tweeters inside or outside on the baffles.

Anyway, having gently lowered them back into a more dignified horizontal position last night, I now find I have an imbalance with the speakers.

Man, you guys were into the Castle (or 4X, or whatever) pretty healthy! Wish I'da been there! 4350's on-end!!??

Anyway, my grab is you should peek inside the quieter cabinet and see if anything was jarred loose. The gizzards of my 4345's are pretty stout and can certainly handle gentle moving around, so I suspect whatever it was that happened is pretty visible.

Hoever, what does not make sense to me is the latter part of your post where you claim the L-pads are less responsive on BOTH cabinets? This makes me suspicious that in your celebratory phase your crossover or amps got re-connected improperly (wrong crossover band pass to the wrong amp or amp to the wrong cabinet connections). I'd start from scratch, taking nothing for granted and do it all fresh. Hell - you might find the vertical orientation was not so bad afterall~!

[Audionutz]

Man, you guys were into the Castle (or 4X, or whatever) pretty healthy! Wish I'da been there! 4350's on-end!!??

Anyway, my grab is you should peek inside the quieter cabinet and see if anything was jarred loose. The gizzards of my 4345's are pretty stout and can certainly handle gentle moving around, so I suspect whatever it was that happened is pretty visible.

Hoever, what does not make sense to me is the latter part of your post where you claim the L-pads are less responsive on BOTH cabinets? This makes me suspicious that in your celebratory phase your crossover or amps got re-connected improperly (wrong crossover band pass to the wrong amp or amp to the wrong cabinet connections). I'd start from scratch, taking nothing for granted and do it all fresh. Hell - you might find the vertical orientation was not so bad afterall~!

Right on several counts Bo !

I think we were all a bit ambitious that day Social lubricants impart such measures of courage !

I agree next step is to have a peek inside. I only run the bass through the crossover, usually at 290Hz. Mid/highs are running full range off the Monoblocks.

Looking at all the pics from the Japanese sites, looks like most folk there have them in the normal, horizontal position, albeit usually on substantial stands. Not to say there's no other way, but given how fanatical those guys are with their big JBL's I would have though they'd tried them on end and gone back to horizontal ....:dont-know

Cheers

'Nutz

[yggdrasil]

When you had the speakers vertically, did you turn the lenses and slots so they kept their normal orientation?

[Audionutz]

When you had the speakers vertically, did you turn the lenses and slots so they kept their normal orientation?

Yes, we certainly did. Bass was definitely more accurate without the floor reflection, but at the expense of mid/highs. Mids especially became "honky" and distorted no matter what amount of toe in/out was applied. Then we tried them with the tweeters outboard on the baffle and sound was very similar. Center image was almost completely lost, along with midrange definition. I had both of these tuned in reasonably well in the horizontal position, which with some 2 inch blocks, raised the tweeters to just below ear level.

'Nutz

[yggdrasil]

Sorry, had to ask...

Regarding the crossovers: I can't remember if there have been posted upgraded networks fort the 4350, you'll have to do a search. And read up on charge coupling before doing anything. It will be worth the effort.

You might get some ideas in a thread by saeman about a vertical 4350 clone he made and called 4351.

Good luck.

[Audionutz]

Sorry, had to ask...

Regarding the crossovers: I can't remember if there have been posted upgraded networks fort the 4350, you'll have to do a search. And read up on charge coupling before doing anything. It will be worth the effort.

You might get some ideas in a thread by saeman about a vertical 4350 clone he made and called 4351.

Good luck.

Will do and thanks for the reminder - probably should have tried that first

Cheers

'Nutz

[4313B]

Regarding the crossovers: I can't remember if there have been posted upgraded networks fort the 4350, you'll have to do a search. And read up on charge coupling before doing anything. It will be worth the effort.

So far I've built six pair of charge coupled 3107 networks. I think they all went to Japan.

[Robh3606]

I agree next step is to have a peek inside. I only run the bass through the crossover, usually at 290Hz. Mid/highs are running full range off the Monoblocks.

Hello Nutz

You are running a full range signal into the amp that feeds the High Frequency section of the cabinet? Why are you not running the top end through the active crossover?? They are a Bi-Amp only cabinet. There is no passive filtering between the 2202 and the woofers.

Now, the other noticeable thing is that the attenuator controls on both speakers seem to have far less effect than previously, when I adjust them.

You should have one per speaker and they only effect the 2405.

I hope you didn't cook them feeding a full range signal into the top end amps.

Rob

[boputnam]

I hope you didn't cook them feeding a full range signal into the top end amps.

Yikes - me too.

I've owned them now for some months - powered by Crown D150 on bass and a pair of Marantz MA-24 30 wpc Class A Monoblocks on the top ends.

So, maybe you ran them this way - at moderate volume - for "months", and then maybe you drove them a bit harder during the "Vertical Party"...?

Ugh - I sure hope this is not the problem. It will be an expensive and systemic repair...

[Audionutz]

Hello Nutz

You are running a full range signal into the amp that feeds the High Frequency section of the cabinet? Why are you not running the top end through the active crossover?? They are a Bi-Amp only cabinet. There is no passive filtering between the 2202 and the woofers.



You should have one per speaker and they only effect the 2405.

I hope you didn't cook them feeding a full range signal into the top end amps.

Rob

Thanks Rob,

When we were setting this up, I tested the signal into the top without a crossover. I got no signal at all through the woofers. I may be wrong, but this seems to suggest that there must be some sort of internal filtering or division between the 2202 and the woofers ....? The reason for doing so was to get the crossover out of the signal path as much as possible. Sounded much better too. The 2405 is still providing sound, which is easily heard. Just the controls seem to have less effect on the 2405 output than previously.

Regards

'Nutz

[Audionutz]

Yikes - me too.

So, maybe you ran them this way - at moderate volume - for "months", and then maybe you drove them a bit harder during the "Vertical Party"...?

Ugh - I sure hope this is not the problem. It will be an expensive and systemic repair...

Hopefully not. I dont run them too hard at any time really. The rooms just not big enough to sound good at higher spl's. As I said, both tweeters are still producing good clear sound, just there seems to be a discrepancy between them. My "gut" fell is its something simpler like the crossover, or that good 'ole "human error" element. I'll be starting from scratch today/tonight and going through the connections from start to finish.

I am however, a little concerned that there seems to be some worry about running the uppers full range. Perhaps someone/s could clarify that for me ?

Cheers

'Nutz

[BMWCCA]

I am however, a little concerned that there seems to be some worry about running the uppers full range. Perhaps someone/s could clarify that for me ?

Well, the upper three elements are designed to handle only the frequencies above the 250Hz crossover point. Your external crossover should cross the woofers at 250Hz as well as the upper section. I would think the 2202 could handle the lower frequencies since it has a huge magnet and a 4" copper voice coil, but that's still not the way it's designed to operate.

Don't know if running full-range could harm the passive crossover in the speaker itself but I'm sure others who build networks can speculate on that point. Regardless of whether you ran it full-range, or not, I can't see how that could have harmed the 2405 unless your amp clipped from running full-range. Perhaps the L-pad has crapped out on you if the only difference you're hearing is in the UHF. But then I once blew an 075 with a low-power amp and JBL told me to check for a "high-frequency oscillation" in the amp. We know the ring-radiators are sensitive to clipping amps. I'm running a D150A-II on the top-end of my 4345s and a DC300A-II for the eighteens, with an electronic crossover set to about 300Hz. I've never harmed a tweeter with too much power. I'm not familiar with your monoblocks. Is it possible they're not up to the task?:dont-know JBL recommends a 200wpc amp for the upper section of my 4345s. Your 4350s are even more robust.

[boputnam]

...I tested the signal into the top without a crossover. I got no signal at all through the woofers. I may be wrong, but this seems to suggest that there must be some sort of internal filtering or division between the 2202 and the woofers ....?

Er, not exactly - there is no wiring whatsoever between the Mid/Hi connections and the woofers. Rob's point is, those Mid-/Hi drivers do not expect to see a full-range signal - there is no Hi-Pass (Lo-cut) filter in that signal path. Ideally, you would use a symetrical crossover point at 250Hz - the Mid/Hi signal would roll-off below that point.

Here's a Link to the 4350B brochure. I'll check our Library to see of the 4350 is there - or pm me your email and I can forward it along.

As I said, both tweeters are still producing good clear sound, just there seems to be a discrepancy between them. My "gut" fell is its something simpler like the crossover, or that good 'ole "human error" element. I'll be starting from scratch today/tonight and going through the connections from start to finish.

I sure hope there isn't something smoked in the crossover. This is one of those times a nice friendly human error in cabling would be preferred!

[yggdrasil]

If you look here : http://www.jblproservice.com/pdf/Net...%20Network.pdf

You'll see that the stock crossover only has a low-pass section feeding the 2202.

Meaning: You need to run your active crossover so that the signal you feed into the top-end are ~250Hz and above, and the signal you feed into the woofers are ~250Hz and below.