chip + circuit recommendation for driving4Wrated speaker/4ohm using bipolar 12v DC

[dnk777]

johnr66: thanks!! that's exactly what I was afraid of. well, then I could perhaps sacrifice 250mA, but for sure I can't afford 1A (1,2A is whole psu and the synth modules needs big part of that). Also 500mA is still too much

i'm a total beginner in this area, so the questions i'm going to ask are probably stupid, but:

1) The speaker's datasheet says RATED POWER = 4W, but most people here advice me chipamps with much more power. is that needed for the speaker to work properly?
If I'd just use a weaker chipamp (lets say 1,5W) with that 4W rated speaker, would the speaker just play more quiet, or is there some other problem as well?

2) if there is another problem and I can't use weaker AMP, then what kind of speaker should I look for if I want the matching AMP to spend only up to 200mA @ +/-12v ?
Should the speaker be rated for 12v x 0.2 A x chipamps efficiency ? (probably not, as i don't have the impedance in the equation and you say that 8ohm speaker would draw less current than 4ohm)

3) what do you think about using a class-d chipamp in this case, where I can't afford to draw 0.5mA, nor add another psu..?

[JMFahey]

Your Power Supply can't feed that amplifier driving a speaker. Period.
Mount the speaker, a chipamp and a suitable PSU inside the speaker cabinet, so it becomes a small powered monitor, to minimize or simplify hook up around your synthesizer.

Edit: just as *one* suggestion: a TDA2003 (not 2030/2050/etc.) is optimized for 12V single supply operation, and provides around 5W RMS into 4 ohms.
Get a kit (or an assembled one) at EBay and feed it from any old 12V wall wart you have lying around.