On 13/12/2016 13:02, Dave Plowman (News) wrote:
In article ,
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.

Piezo sounders tend to be tuned to a particular highish frequency for best
efficiency. Perhaps ideal for an alarm, but not sure I'd like that nasty
noise as a door bell.

Piezo speakers can be made to do a range of sounds and tunes and are
plenty loud enough for a domestic dwelling. It isn't hifi but neither is
it just a manky fire alarm klaxon. Flash mode too for totally deaf.

https://www.amazon.co.uk/Byron-BY301...dp/B005JBN3V8/

--
Regards,
Martin Brown