Lower output on other channel's midrange

I noticed a while ago that my right speaker’s midrange is significantly lower in output. Tweeter and bass woofers are fine, so would this have to do with the crossover?
The driver itself seems to be fine, I checked the spider, etc. It doesn’t distort, just the excursion is very limited (seemingly limited in terms of signal, not mechanically, as the cone when pushed moves as easily as the left channel’s) - strangely, I noticed this when checking by hand. Proves again how changes in amplitude aren’t so distracting to us. The stereo image even is fine, compromised though of course.
Could it be anything else than the crossover caps causing this? Or is it possible for a driver to fault this way without it being apparent upon visual and mechanical inspection?

To be honest this is extremely frustrating BUT this might give me an opportunity to delve into the world of tweaking crossovers with overpriced capacitors and whathaveyou…!

Just swap the drivers over. A damaged voicecoil can still work but not as it should.


Well I might do that, bit of a hassle but indeed I need to locate the problem…
Do you think a lower output without any distortion could even be a common sympton of a damaged voice coil?

If it’s damaged… Damn, it’s a special driver that Audio Physic has further tweaked for these speakers and it’s not in production. I guess replacing a voice coil, then again, isn’t such a big job for a professional in an audio repair shop? Or is it…

I can see no choice but to swap the drivers. I once overdrove a tweeter with a test disc. I could smell the voicecoil overheating. It continued to work, apparently fine, for about two months and then failed completely. It’s possible for voicecoils to get so hot that the windings join together thereby changing the impedence and altering sensitivity (it’s worth testing/comparing voice coil impedences, it’s often a little different but only by maybe 5%). Often when voicecoils short they will also start to rub.

This I see as a possible cause, the other possible symptoms of failure not. If the sensitivity is now significantly lower it’d lead to lesser output, right.
I kinda want to get to work with swapping the drivers but not until I’ve listened my dose of music today (lazy). Fortunately this issue does not significantly alter the soundstage as mentioned, because it’s only a matter of lesser amplitude. Humans aren’t that picky about amplitudal changes, more about frequency arrival coherence…

It’d be worth pointing a db meter closely at the mid and tweeters to check the outputs with white or pink noise. Yes, I presume a lowering of impedence would cause a drop in sensitivity.

If you take drivers out make sure you put the connections back the same - some designers actually put drivers in reverse phase!

It could even be something as simple as a poor connection at the crossover.

I’ve some old four-way speakers and each driver measures slightly differently but they still sound ok.

Right, I switched the drivers and yes, the problem persists. It’s the crossover.

Bother. :frowning:

A bother but then again, this will lead me to redo the whole crossovers with hand-picked better quality components when I have the money. My nature will not allow me to simply fix a problem like this, I have to make it better.

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How old are your speakers?

Tough one here but if drivers no longer available…
time for new spekers?

It is tough call…

Best wishes

Well since the issue is with the crossover, is it most probable that it’s a midrange subcircuit’s capacitor that has shifted in value to cause lesser output?
I don’t necessarily want to redo the whole crossover nor do I want to take it all apart to find the faulty part… Any other passive component in the circuit than a capacitor that could do this? Can a resistor also cause this by becoming, well, more resistive for some reason?
My friend drove the speakers fairly hard some time ago, more than the recommended 150W at least.

You wouldn’t need to change all components in the crossover.

Firstly check all the connections then look at the board for obvious damage such as burnt resistors or components that have come unsoldered.

Then you need to work back through the circuit (it’s almost certainly a single layer board). You will likely find that with a three way speaker the crossover will split into three sections (if it’s biwirable then you can easily discard the bass section and then work out which components are associated with the mid/tweeter section, They’ll likely share a common trace until they split into the separate sections for mid and tweeter). There are unlikely to be many components to any one section and the treble is likely to be very simple with very small components in it. Once you’ve worked out which components are for the mid you can then come up with a strategy for swapping things between the two crossovers, or give the crossovers to someone who’ll do it for you. My 2p worth.

Out of interest (to me anyway) when I had my 4-way speakers I could clearly see which sections were for each driver and I could cut the tracks on the board to convert it into a 4-way ampable speaker.

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To be replaced with:

(Realized I had some fairly nice 10uF caps, so why not do this… it somehow even fits in the enclosure!)

I ran into a similar problem years ago with my B&W speakers. Turned out the ferrofluid in the voice coil thickens and hardens to the point where the driver couldn’t work properly. The solution offered by my audio technician was to disassemble the driver, clean out the existing ferrofluid and put fresh fluid in again. But a couple if years later it happened again so it had to be disassembled and freshened again. The speakers live on i a closet now. They look nice but…

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How did you determine it was the fluid which was the problem?

The tech determined it when I brought the speakers in for repair. I was hoping to replace the tweeters with new ones but they are no longer available. Hence the infinite storage. I don’t know what i hope ti accomplish with them. Apparently its a common problem.


It’s one thing to blow a voice coil or for a speaker to suffer dry rot from climate or age, but this sounds like a substantial design flaw, no?


That’s one of the things that can crop up with aging “new” tech. There isn’t time to fully age the parts in the test lab before they need to be released for public sale.

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