Wow! Magnet, voice coil, phase plug ripped out...

awillia6

Super Member
Monitor Audio Gold Reference Centre limped in today via USPS for some outrageous shipping price (my cost was limited). The speaker, over 25lbs, was decently packed in multiple layers of cardboard, each tightly shrink-wrapped around the speaker and inner layers, the whole works which was then wedged into a shipping carton. well-sealed with plenty of strong, wide shipping tape. Shoulda lived, but...

When I lifted the shipping carton to put it into my trunk, I heard and felt something go "thunk." That can't be good, I thought. After unwrapping everything, one of the two main drivers was missing its phase plug. On closer inspection the driver cone was deformed and the whole back end of the driver had come detached and was rattling around inside the speaker cabinet. That shipping carton must've taken a helluva drop to separate the driver into its constituent components like that. Back it goes, but first I'll ask if the seller wants me to go in and secure the loose guts so the remaining driver, the tweeter, and the crossover don't sustain damage (at least any more than they already have). Shit.

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Kinetic energy + common carrier handling = unhappy campers.

With a load like an assembled speaker some of the cushioning inside the package must allow some "give" to dissipate shock energy.
 
Almost makes you want to stuff the inside of the speaker. Easier to cushion raw drivers against this than assembled speakers. Bowtie is right though, the outer packaging has to be able to absorb some of the impact. Too rigid and the G force is transmitted too efficiently.
 
Actually the center speaker was pretty decently packed. I've certainly seen MUCH iffier packing whose contents arrived without any damage at all.

After going to war with USPS, who paid the insurance claim AND eventually refunded the postage (which I forwarded to the seller), I figured I'd see what exactly could be done with the "carcass."

Getting into the unit, I discovered more evidence of the abuse it suffered. The drop was so severe, it detached a crossover coil from the crossover circuit board, breaking off a small section of the PCB containing the solder pad. Cripes, those guys must've dropped it on its ear from at least 6ft up to do all that internal damage.

So:

I repaired the broken crossover PCB and checked that all components and connections were operable and on spec.
I epoxied the magnet assembly back onto the driver's basket AND glued in the now-rattling phase plug. The other driver's plug was also loose so glued that too.
I CAREFULLY bent the driver cone back into a very good facsimile of a pure conic (helped that these are metal cones).
Hooked up all three drivers to the crossover outside the cabinet, fired up my system, and everything seemed to work but sounded awful.
Glued in the cabinet's acoustic foam pieces (I hate relying only on friction to keep them in place).
Bolted up all the drivers, the crossover, and cleaned everything up.
Did a -15db full-range burn-in for about 4 hours, checked all drivers for fit and function (sounded glorious), and checked this project off the list.

Ended up with happy seller, happy "buyer" (me), and the USPS paying for their carelessness. All's well that ends well.
 
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Kinetic energy + common carrier handling = unhappy campers.

With a load like an assembled speaker some of the cushioning inside the package must allow some "give" to dissipate shock energy.

THIS is the key. But, there is a point where no matter how well you pack, things can be destroyed.
I pack for "normal" handling. A lot of you may freak out by the small amount I use. 99.9% arrive fine.
I've had things shipped in with very little good packing, some with very poor packing and survive.
 
Kinetic energy + common carrier handling = unhappy campers.

With a load like an assembled speaker some of the cushioning inside the package must allow some "give" to dissipate shock energy.

This. Cardboard will not do. It has to be furniture grade bubble wrap and medium density styrofoam sheets. Construction grade styrofoam is too hard and will transmit shock. Speaker will look perfect on the outside but havoc on the inside.
 
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