Enough to practically rattle my car apart. My parking mirror fell off within a week. See last picture for full specs list. I tuned my amp with an oscilloscope, so these subs were never sent a clipped signal, and therefore the voice coils are in great shape.
All coils reading the correct resistance after accounting for the internal resistance of the multimeter probes (see photos). This particular model of Deaf Bonce subs is almost impossible to find nowadays, good luck finding another pair for sale! Will be well packaged with padding and lots of tape.