Terry Morse writes:

Spokes never break in the center. 90% of the time they break at the
elbow, the rest at the threads, that's where the residual
manufacturing/building stresses are.

Never say never. I've seen a spoke break in the middle before, and
it makes a pretty spectacular noise. The culprit was corrosion,
probably started at a surface scratch.

As I said, most of my spoke failures are from nicks made by the chain
falling into the spokes (because the end stops of today's derailleurs
are too short to prevent going past the lowest sprocket on my 6-speed
FW's). The exception was a failure in the middle that showed no
indication for its failure with no crack propagation, only a slightly
sloping complete separation and no necking. When it went, it sounded
no different from any other spoke failure, like a small hammer blow on
the hub.

Jobst Brandt

Palo Alto CA