Coaxial Bass Speaker

lcw50 · #1 03-18-2013, 06:47 AM

I have an Eden CX-210 cabinet loaded with 2 10" speakers, one of which is a coaxial. This coax had a voice coil buzz or scratching noise so I sent it out for re-coning. When it came back repaired it played for a few minutes scratch-free but then shortly thereafter started to make the same buzz all over again! I sent it back to the repair shop and had the same exact results, 2 more times! This speaker has 2 separate magnets - Is it possible that the upper "added-on" (high frequency) magnet structure is not aligned properly causing the cone to move off-center? Is there anyone who has had any experience re-coning a coax like mine?

KJung · #2 03-18-2013, 06:56 AM

Sounds like the problem is not the speaker

Arjank · #3 03-18-2013, 07:42 AM

Not all coaxial drivers are designed the same so it's hard to tell.
If you wiggle the 10" cone with your fingers(slightly push the cone downwards with your fingers around the dustcap, or voice-coil if there's no dustcap). Sometimes you can feel the voice-coil scraping some other part of the assembly. If not, you can try to feed the woofer part of the coaxial driver with a sine-wave of e.g. 30hz (start with low volume). If no buzz appears you may want to do a sine-sweep from 1khz to 6khz through the high-frequency driver to make sure this one isn't the culprit.

fokof · #4 03-18-2013, 07:56 AM

Not all product are created equal.

Maybe a bad reconing job?
Have you send it to the same shop all those times?
You usually have a little warranty on repair jobs.

Maybe try another repair shop......

I use coax speakers a lot where I work as PA , front fill and monitoring kit , L'Acoustic brand , we had a couple reconed over the years without any problems.
These are very well engineered product , costing mucho pesos though...
I also use one as a bass monitor , sounds incredible! (108P)

T-Bird · #5 03-18-2013, 10:00 AM

Hi.

My vote would go for a magnet or other ferromagnetic fragment in the VC gap.

If that's the case, the basket is toast.
It also shows lack of judgement from the re-coner to recone such a basket.

Regards
Sam

1958Bassman · #6 03-18-2013, 10:15 AM

Quote:

Originally Posted by lcw50

I have an Eden CX-210 cabinet loaded with 2 10" speakers, one of which is a coaxial. This coax had a voice coil buzz or scratching noise so I sent it out for re-coning. When it came back repaired it played for a few minutes scratch-free but then shortly thereafter started to make the same buzz all over again! I sent it back to the repair shop and had the same exact results, 2 more times! This speaker has 2 separate magnets - Is it possible that the upper "added-on" (high frequency) magnet structure is not aligned properly causing the cone to move off-center? Is there anyone who has had any experience re-coning a coax like mine?

Can you post a photo of the rear of the speaker? If it looks like a compression driver, remove the HF unit and try the bass driver, on its own. If that works well, see if the diaphragm is removable and, if it is, remove it and make sure it's positioned properly. Also, look for dark stripes on the voice coil- if it does, it's from over-powering, high amounts of distortion, or both.

seamonkey · #7 03-18-2013, 12:42 PM

Maybe the HF driver needs a new diaphragm

RockNRollAl · #8 03-18-2013, 04:11 PM

Hold on... Is there a 1/4" jack right behind the speaker? Sometimes they buzz from the air rushing through it, but the sound seems to come from (through) the speaker. A foam earplug fixes that problem. It's a common complaint with Eden cabs.

Arjank · #9 03-19-2013, 01:31 AM

Quote:

Originally Posted by fokof

I use coax speakers a lot where I work as PA , ..... I also use one as a bass monitor , sounds incredible! (108P)

+1 (though this is off-topic)

I use a coaxial driver from 400hz and up for my bassmonitor and I don't want anything else.

Alper Yilmaz · #10 03-19-2013, 01:41 AM

This might be an over-simplified version of what the OP has been experiencing, but what he/she has is similar to Bag End's coaxial drivers, I had a similar problem once with my S15X-D. At the end, I figured out that the tweeter unit was a bit loose, and by turning it (from the back of the driver) clockwise, I fitted it again and got rid of the buzz.

DaveAceofBass · #11 03-22-2013, 09:32 AM

Eden is very unreliable gear. Saw too many duds come fresh out of the box when I sold them at the music store.

DukeLeJeune · #12 03-22-2013, 03:35 PM

Quote:

Originally Posted by Alper Yilmaz

This might be an over-simplified version of what the OP has been experiencing, but what he/she has is similar to Bag End's coaxial drivers, I had a similar problem once with my S15X-D. At the end, I figured out that the tweeter unit was a bit loose, and by turning it (from the back of the driver) clockwise, I fitted it again and got rid of the buzz.

I use screw-on compression drivers mounted to horns, and like to put a drop of blue loc-tite on the threads just as insurance against the compression driver unscrewing itself over time. My guess is that the vibrations are stronger if the compression driver is screwed directly into the back of the woofer, so a drop of blue loc-tite (or auto parts store equivalent) would make even more sense there. Do not use the red stuff, it grabs too hard.