On Tue, 13 Dec 2016 11:29:23 -0000, wrote:

On Tuesday, 13 December 2016 11:05:08 UTC, wrote:
Piezos are very power efficient but they just don't have the
required volume. Old mechanicals do.

Piezos and other electronic sounders have just about replaced conventional bells in fire alarm systems due to low current requirement enabling more sounders to be used, for uniform volume coverage.

My doorbell uses a small paper cone 2" speaker. It's as loud as a mechanical chime and lasts the lifetime of the 4 AA Duracells.

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