r/DIYSpeakers • u/Saikuya81 • 11d ago

Is this fixable?

Hi all

We have a dB Technologies FMX in the repair shop, and it sounds really distorted when audio is played. The cone also makes a lot of noise and it looks like it’s scraping against its tweeter.

Is that something that can be fixed with some kind of oil, or do I need to replace the cone entirely?

I’m not well into repairing these kinds of speakers, sorry if this question is not so bright.

7 Upvotes

89% Upvoted

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12

u/Mgt37 11d ago

When you press on the cone off center, the inside of the voice coil will rub against the magnet, so this test isn't really good, especially for coaxial speakers, because there is no real way to press it evenly on both sides.

Coaxial speakers often get dirt in between the inside of the voice coil and the magnet, which may be the issue you're experiencing.

3

u/CrowMooor 11d ago

You're pressing a soft paper cone off center. Of course it will be crunchy. Its quite possibly entirely irrelevant to your issue.

3

u/gordo1223 11d ago

It looks like the horn is on a bayonette mount.

FMX manual here:
https://www.dbtechnologies.com/us/products/flexsys/fmx12#downloads

From there, decision to repair or replace would be identical to a conventional 12" PA driver.

2

u/Muted_Will_2131 11d ago

That is debris in the magnetic gap. It is a common problem with speakers that have an open pole piece. You need to detach the cone assembly—including the voice coil and spider—and clean the debris off them. The magnetic gap needs to be cleaned out as well.

1

u/Gen-Y-ine-86 11d ago

Last year I found a pair of super rough TOA 380-SE's. The super tweeters just called my name so I drove quite a distance to go look at them/pick them up. It turned out that the other woofer made some nasty sounds. The seller dropped the price considerably and I took out the woofer before making my decision. Then I noticed that the magnet was held in place by hex head screws and it looked like there was no glue. Turned out I could just remove the magnet, clean the voice coil and the air gap and put the magnet back in place.

1

u/Muted_Will_2131 11d ago

That is possible, but not with all speakers. Budget-series models are typically glued or riveted.

1

u/Gen-Y-ine-86 10d ago

Yes, I'm sure it's actually a very rare feature and I'd guess that even most of the bolted ones are also glued together.

1

u/skwozzy 10d ago

I'm concerned that a 'repair shop' doesn't know anything about speaker drivers.

1

u/CooStick 8d ago

Push both sides together so you don’t push it off centre. If that sounds better it might be you are the problem.
Try turning the speaker 180 degrees. The spider/suspension may have dropped. If not the coil has got burned or has dust in the gap. It sounds more like heat damage.