Hello Everyone; I've been swamped and haven't had any time for Robot fun:( But I came across a display of this product that is a 1" cube Speaker for your MP3 player that also has a rechargeable lithium Battery that charges itself from a USB port:) This would be great for adding a voice to even a tiny Robot!:) and at Walmart, it was under $11.00!
https://www.getboomcube.com/IDVBC/1.0000/index.dtm?mid=2787519
I saw this product too at Walmart, however I came to find the music bullet another really good source of speaker output for robotics as well!
The best speakers are usb laptop speakers. They can take a 5v input have a built in amp and are usually much louder and better quality than non amplified speakers.
The Boom Cube are powered. And only 1inch square.
Ah neat