Patent ID: 7236609

Claim:
A transducer comprising: a pair of spaced magnets, the pair of spaced magnets forming a first passage; a coil, the coiling being formed to include a second passage; the first passage and the second passage respectively forming a first portion and a second portion of a tunnel, the tunnel having a central axis, a first side wall and a second side wall, the first side wall and the second side wall defining a nominal tunnel width, and a first upper wall and a second upper wall, the first upper wall and the second upper wall defining a nominal rib gap; a reed having a central portion that extends through the tunnel, a stationary end and a deflection end, wherein the reed has a tip portion that lies at least partially within the first passage, the reed being mounted such that a portion of the reed is free to be deflected towards or away from respective ones of the pair of spaced magnets; the coil having a first end disposed toward the stationary end and a second end disposed adjacent the magnets; the pair of magnets having a first end disposed adjacent the second end of the coil and a second end disposed toward the deflection end of the reed; the tunnel having a tapered portion, the tapered portion either increasing or decreasing the nominal rib gap at the tapered portion, wherein the tapered portion comprises each of the first portion or the second portion.