shifted magnet- suggesrions? Pics included....

[thedelihaus]

I have a nice cast driver woofer from a Royd (“The best loudspeakers you’ve never heard of…”) which were hand built by owner of Royd, Joe Ackroyd, in Telford, UK.


Got them with a bad woofer. Judging by the giant chip in the cabinet, I wagered a bet and took the chance the driver wasn't blown, but the magnet had shifted.

They arrived, and besides a slip removing the rubber surround from the cone (a health issue causes occasional hand numbness and loss of control), got the surround off.

Later, I need to address the small 7mm tear the above caused in the surround, and a small cone wrinkle in the paper cone. Dang!

I figure RTV silicone and a small patch behind the tear.

As for the paper cone wrinkle, Any suggestions?




Back to the magnet- you can see the magnet is in fact two magnets stuck together.


The back magnet is the one that has slid and pinched the voice coil.



I have a few ideas for aligning the magnet-

1) remove the cone and lead wires

2) match a piece of pvc pipe to the magnet size and notch out a 1cm split lenghtwise

3) "wrap" the pvc section around the magnets, attach a few radiator hose clamps and tighten them 'till the magnets re-align.



HERE'S THE QUESTIONS-

Should the magnets be glued together? I don't know if they ever were or if they were just held together via gravity. If so, how do I separate the two rings of the magnets, and not chip, crack or damage them?

Any suggestions on checking the alignment of the voice coil hole through the magnet? If it needs re-alignment, any suggestions?

Is there a better way to align the magnets than my solution?


NOTE- the bottom magnet that attaches to the metal frame HAS NOT SHIFTED. It's the second, rear magnet that's got me concerned.

Here's some pics...

[socal sam]

That's a tough one. Removing the cone and VC makes sense, hopefully the pinch didn't break continuity. Magnets tend to shatter when struck or forced so your clamping strategy makes sense.

The wooker must be rare and expensive because of the boutique nature of Royds. If it was an ordinary woofer, I might use a couple of pieces of wood and a hammer to strike them back into place.

If you have a crappy or busted woofer, you could practice striking the magnet to develop a sense of how much the magnet can take before shattering. My ONE CENT, definitely not a professional solution. Good luck!

[Lazarus Short]

Face it - there is a very real probability that the voice coil is bent or cut. Is there electrical continuity? Try to align the magnets with a stout hose clamp of the proper size, or an automotive piston ring compressor. Is there any woofer repair shop in your area? Good luck with it!