How subtle can a bad tweeter be?

[240zracer]

My DIY speakers are Eton 11 inch, Scan Speak 6 1/2 inch, Scan Speak Revelator 2905/9900. There are some miles on them, but I really like them. In fact, I just completed a major crossover upgrade. The problem: Center image is slightly off to the right. So I disconnected the woofer and the tweeter and played an imaging track. Dead on center. Add the tweeter and image moves slightly right. Then for grins, I changed the polarity of the right hand tweeter. Image is very close to center. (changing polarity on the left tweeter has no effect on the image). So I swapped left and right crossovers. No change, meaning it is not a crossover issue. I have checked all the wiring and nothing is mis-wired. So.....do I have a tweeter that is going bad?? Which one? I think maybe, just slightly, I hear a little grain from the right and it definately wants to play louder than the left......seems a lot of echo and ambience come from the right as well. Any ideas?

[dantheman]

Can you take measurements?

Not sure what the replacement dome assembly costs, but it shouldn't be too much.

Dan

[AllenB]

Try rotating all your RCAs in case they have developed a bad connection.

[Cal Weldon]

I have had the same problem AllenB. It was a ** to finally zero in on it.

[tinitus]

Originally Posted by 240zracer

So I swapped left and right crossovers. No change, meaning it is not a crossover issue.

I have experienced exactly that
and it was caused by crossover
and how can I know
because a crossover adjustment changed it

not because of imbalance between each channel xo, as one might expect
but something strange related to summed xo function, in both channels

I suspect small micro phase changes
it seemed to cause ambience to draw more towards one channel
I have also experienced some parts of an instrument 'dragged' towards one channel, while some parts of the same instrument seemed to be more present in the opposite channel
that too was caused by crossover(malfunction)

that you can get it more centered by reversing polarity on just one tweeter indicated that this may be the case here too
but still a small mystery why it happens
still, it is possible
though logical its certainly not

[tinitus]

well, you have tried to switch xo, left/right
I suppose you have tried to switch tweeter too, left/right

but maybe Allen and Cal are right about the connectors
would certainly be easier

[kevinkr]

Originally Posted by tinitus

I have experienced exactly that
and it was caused by crossover
and how can I know
because a crossover adjustment changed it

not because of imbalance between each channel xo, as one might expect
but something strange related to summed xo function, in both channels

I suspect small micro phase changes
it seemed to cause ambience to draw more towards one channel
I have also experienced some parts of an instrument 'dragged' towards one channel, while some parts of the same instrument seemed to be more present in the opposite channel
that too was caused by crossover(malfunction)

that you can get it more centered by reversing polarity on just one tweeter indicated that this may be the case here too
but still a small mystery why it happens
still, it is possible
though logical its certainly not

Easily enough checked by swapping the left and right speaker systems and seeing if the issues stays on the right channel or moves to the left.

It is also potentially the case that there is an amplifier problem that is at the root of this problem - if the problem moves with the speaker it is speaker if it doesn't could be the amplifier.

Another thought is how the two speakers are placed relative to your listening position - if they are not symmetrical all sorts of weird things can happen. Tweeters often have limited off-axis dispersion and will sound much brighter if heard on axis than even slightly off axis.

Make note of other obstacles in the way and reflective surfaces that may affect one speaker more than the other. (Stuffed furniture, reflective glass coffee tables, plants, absorbent wall coverings, etc..)

[240zracer]

dantheman, this is very subtle. Center image drifting to the right about 18 inches. I wouldn't know how to measure it. AllenB, rca's would affect all the drivers, not just the tweeters. tinitus, you scare me because I cannot imagine how my crossover could cause it. The two tweeter crossovers are mirror images, stand-alone, outside of the enclosure, Duelund Cast and Mundorf S&O caps, Duelund resistor, hand-measured inductors. Scares me because I know it is possible cause all things can happen with crossovers. kevinkr, actually I have not swapped left and right speakers since I discovered this problem. I will try that. My amp is recently serviced and is balanced, and as I said, I get a dead center image with only midranges and only woofers hooked up. I'm still thinking that one tweeter has a problem and the inverted phase is cancelling the effect of it somehow.

[AllenB]

Originally Posted by Cal Weldon

I have had the same problem AllenB. It was a ** to finally zero in on it.

Like when I finally knelt on mine while poking around an amp? I've stopped using the cheap ones because they seem to bend and work loose.

[tinitus]

Originally Posted by 240zracer

tinitus, you scare me because I cannot imagine how my crossover could cause it. The two tweeter crossovers are mirror images, stand-alone, outside of the enclosure, Duelund Cast and Mundorf S&O caps, Duelund resistor, hand-measured inductors.

wow, you have really spent some serious money on your upgrade

I think you need to measure every each component
considering the cost of your upgrade, a special inductor/cap meter is small money
actually, every diy speaker builder should have one
the bad thing is, you probably can't change values on any of those components
all you can do is checking if they actually have the correct value you have ordered

do you have a schematic of your crossover ?

and I would like to see a picture of your xo layout
inductors 'talk' to each other if close together