Eminence Magnum 18LF rattle

[paulspencer]

I've recently purchased a pair of Eminence Magnum 18LF woofers, one of them in a box so far and it rattles! Initial though was that the off centre VC was rubbing against the phase plug, but pressing it in manually doesn't reveal any rubbing. There is a flywire screen pointy dust cap over, it's flimsy and I suspect it's the cause. Has anyone had experience with this driver? I'm wondering if this is a design flaw, or something else. Considering removing the fly screen which appears to serve no important function.

[pinkmouse]

Stick the driver on the bench and feed it some 20 Hz to get it moving, (and hopefully rattling). Run your finger around the surround, spider, and dust cap in turn, and at some point, you will hear the rattle stop, or get worse. That is where the damage is, and hopefully, is just a dried out glue joint, rather than a split or tear.

If that doesn't work, still while feeding it 20Hz, push down firmly on the cone in each of the four quadrants, this will show if the VC is out of alignment.

The other thing to check is that the tinsel leads are bent well away from the cone, as these can cause rattle with high excursion.

[revboden]

also check that the cable is secured and not rattling against the side of the box, i've had problems with this and it is very frustrating as it only happens when the box is back together and you can't see what's happening. thin water pipe foam insulation tubes work well as conduit.

[wg_ski]

The dust screen could be the cause. And it could be just turbulent airflow around the phase plug or through the screen. There may also be something in the gap - it doesn't take much to get it making noises. Try gently applying a vacuum cleaner hose over the phase plug area to get any grit, hair, dust, etc out of the gap. I get stuff stuck in my 5K4211's from time to time, and the vacuum gets it out.

[paulspencer]

Thanks for the suggestions guys, haven't had a chance to look at it properly yet

[evanc]

I feel for you ........A couple months ago I thought one of my subs was rattling. I couldn't figure it out for the life of me. It turned out to be some sticks of moulding I had stored in the space between the floor joists in the basement.

[Tajzmaj]

I have such case with Beyma12kx. It was badly glued dust cover.....at the new unit....grrrr. And it shows up at the live gig. In a brand new monitor....so we firstly check everything else. Power amp, graphic eq, aux channel.....cables. We solve it right there with some latex glue. Uf ugly but efficient at the field solution.
Regards, Taj