Yes I know but it isn't meant to generate sound... I estimate that less that 100 mW total will be required and all moving parts will be mechanically isolated... Simple enough to do with some foam and silicone based adhesives... Further If both the x and y axes are fed the same linear ramp signal, properly phased... the Red Laser diode could be pulsed on/off for a 'Vector Display'[ device... great for displaying text too...
Red is the only even half safe color to use, Blue will cause permanent eye damage at 1/2 mW power levels and green isn't much better, VERY dangerous because of the possibility of 'accidental' reflection. Initially small speakers will be the 'linear' drivers for a proof of concept design... Later well???
Doc