Alnico won't attract much metal...
Quote:
Originally Posted by morbo!
Do metal objects fly toward them???
I dont know how much charge they supposed to have.
But the only thing i would do to the actuall driver by the look of the photo is a recharge if a shifter wont stick to it
maybe ill get in all kind of shit for this!
Unlike Ceramic/Ferrite magnets, Alnico magnets have very little "stray" magnetism and do not hardly attract ferrous metal to them even when they are newly charged. So this would hardly indicate a weak magnet.
shorting terminals= infinite damping factor
If you ship a driver with a high-compliance suspension, it couldn't hurt to connect a shorting lead between the speaker terminals. Lord knows what those packages are subjected to bouncing down the road, going through conveyors and chutes in Dist. centers, etc.
We used to have sensitive analog instruments that required a shunt wire across the leads to damp the meter's needle movement during storage and transit. Makes a major difference in the effect of vibration on moving the needle; same goes for subwoofer cones.
Quote:
Originally Posted by moldyoldy
Just a side note for any that try the "manual" method. The driver in question MUST be disconnected from amps, networks, etc., or you'll likely condemn a few good speakers this way. When the coil is moved manually, it acts like a microphone and produces a signal. If the coil "sees" any load connected, you'll feel/hear what you'll swear is a coil rub. The effect may not be noticeable on cheap, inefficient speakers, but it sure is on the close-tolerance, efficient drivers we mess with. Next time you've got a loose 15" on the bench, throw a jumper across the terminals and try it. I've even checked for open coils in the field when I was without a meter or battery this way.
Typical disclaimer, don't try this at home, etc., etc. It DOES require a practiced touch.