Recommend a small and loud speaker

I'm working on a project that needs a purdy dang small speaker, but it still needs to be loud enough to be heard clearly from about 10 feet away.  Now, I know that when you loose size you loose watts and when you loose watts you loose volume, but I was wondering if anybody could recommend a speaker 50-ish millimeters or less in diameter and loud enough to be heard clearly from 10 feet away.

If it helps, I'm working with an Arduino with an Adafruit Wave Shield to make a human voice speak English (American-ish).

Thanks for the help,

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orksecurity7 years ago
Almost any small speaker will do the job, I expect. Ten feet really isn't much, and if all you want is voice you don't need a huge frequency range or tremendously accurate reproduction. A scavenged speaker from a busted clock radio or cassette player or something of that sort would work; those are typically about 2" diameter with an 8-ohm coil, and 2" is pretty close to 50mm.
Schmidtn (author)  orksecurity7 years ago
Thanks, I ripped apart an old MP3 player speaker set and harvested one of the speakers. It's actually 4 Ohm, 1 Watt but it's much clearer than the one I picked up at RadioShack and half the size.
(I'm listening to a small radio right now from farther away than that.)
NachoMahma7 years ago
.  In addition to the recommendations given by others, I'd use a high-pass filter in front of the amplifier. Your small speaker will not reproduce any bass to speak of, bass is not required for speech recognition, and it uses a lot of power. Save your power for mid-range frequencies.
That does sound entirely reasonable
Good idea.
The case you put the speaker IN makes a lot of difference. A nice thick wall stops the case cancelling out the speakers emissions.
lemonie7 years ago

it'd be "tinny" but you can get pretty loud piezo devices.