Uneven Loudness

[ngccglp]

Hi,

I noticed the freq response of my 4430 L/R varies, when both sides mid and high lpads are set to 0, one side seems louder than the other side. Also the freq response seems uneven, in that I mean like for voice the imbalance seems ok, but for saxaphone, the sound would drift to one side.

Is this caused by the crossover or the compression driver? would changing the diaphragm works?

Thanks

[Fred Sanford]

Actually, I had similar symptoms with 4333As and it was the original equipment input terminals oxidizing. Sometimes when the music would naturally get louder the sound would balance back out, too. Cleaning them helped for a while, then setting them up for bi-amping has been OK for a while, and I'll be replacing them with new next time I have the whole mess apart.

Good luck,

je

[JBLRaiser]

Hi,

I noticed the freq response of my 4430 L/R varies, when both sides mid and high lpads are set to 0, one side seems louder than the other side. Also the freq response seems uneven, in that I mean like for voice the imbalance seems ok, but for saxaphone, the sound would drift to one side.

Is this caused by the crossover or the compression driver? would changing the diaphragm works?

Thanks

Switch your speaker wires, if the problem moves to the other side, it's not your speakers.Then switch each components' wires until you find the culprit.

[hardtime]

Don't forget to swap the speakers (right to left) to see if the problem follows.

[ngccglp]

I did swap the L/R connection and confirmed that the problem is with the speakers and not the CDP, AMP.

could it be the capacitors in the XO has reached their useful life? If that is that case , bi-amping will not solve the problem because the circuit for the HF will not be bypassed. Is it difficult to change the capacitors? Are they still avail or are there substitutes?

Thanks

[johnaec]

What happens if you turn the controls up and down a bunch of times, then leave them all the way up, which theoretically is "straight-through"? What's the balance sound like then? I know the settings wouldn't be ideal, but at least you should be able to compare them.

John

[jbl]

The internal speaker wires can oxidize leading to a higher resistance effecting the output level.
Strip new internal wire connections as well as clean the L-Pad. It may solve your problem.

Ron

[grumpy]

I've found it helpful to use a monophonic source (or pre-amp setting) when chasing
this sort of thing down. I don't happen to have a stereo-mono preamp switch, but can
set my FM tuner to mono (as an example).

... additionally suggest you give the biamp/passive switch a rigorous workout
(clean if practical). L-pads are probably your best target for focus, albeit a bit
of a pain to get to... (heat gun or hair drier + spackle tool or spatula to remove
name plate)

[Skywave-Rider]

If you can, pry open the Lpads and spray in first Caig Deoxit; give it a good bath. Then spray in some Deoxit Gold.

Last time I did this I destroyed the decals which covered the attenuator. But the pot worked right again.

[Chas]

My 4430's had corroded bi-amp switch contacts. Try rotating them back and forth a few times. When I finally opened mine up, I also blasted them with some Caig.

[ngccglp]

I don't think its the Lpads. when I rotate them, there is no noise which would indicate that they are in fairly good working condition. I also tried the biamp switch. I will try biamp this weekend.

Also thinking of building the XO from scratch so that I can avoid the trouble of taking out the name plate.

[grumpy]

If you're planning on going through all that (fun project that it would be) ,
why not swap horn/driver assemblies to narrow it down to crossover vs.
compression driver issue (which I believe you speculated earlier)? Only
six hex-head machine screws per speaker.

[ngccglp]

Took a peek at the crossover, noticed a iron core inductor that looks like a mini transformer.

If I build my own XO, do I need to use the same type of inductor? Don't think they are avail anymore.

[grumpy]

To not alter the design, the same value and DC resistance are a minimum criteria
for a replacement inductor. Current/power-handling capability in say L102 (2.6mH),
the off-board inductor, would also be good to match (at minimum). I seem to recall
someone having posted a suggested N3134 parts list and perhaps DCR.

Something like this would work (in an overkill/feel-good sort of way):
http://www.partsexpress.com/pe/pshow...number=266-910
(take off a few turns if the 4% + tolerance value bothers you... good to measure
and match them anyway)

The equivalent air-core inductor could easily cost 2x, but "different strokes..."

[doodlebug]

I had a similar problem when I refoamed a set of 4425s. Since I had never heard them running right (purchased at a yard sale in sad condition), I figured that there was a bit of mid-range 'suck-out' with the speakers. What I found I had done was not wire one of the woofers correctly after I had reinstalled it after refoaming. Your symptoms sound somewhat like I was hearing.

I'd be in there confirming that the drivers are, indeed, hooked up correctly - especially if they have been opened up before.

Hope that helps.

Cheers,

David