i am hoping I can put several in parallel to dropthe eff resistance to whatever the minimum the amp can handle
Quotei am hoping I can put several in parallel to dropthe eff resistance to whatever the minimum the amp can handleA Bad, bad, bad, idea! The general rule is NEVER connect outputs together. (That's why you use an audio mixer to mix audio signals.) Solid state amplifiers have very low internal source impedance (often less than one Ohm). The output of one amp "shorts out" the output of the other.The most common "trick" is to make a bridge amplifier. That doubles your peak-to-peak output voltage (theoretically 26V P-P = 9V RMS) with a 13V power supply) and that gives you 4 times the power into the same load. Doubling the voltage doubles the current, so an 8-Ohm speaker "looks like" a 4-Ohm speaker to each amplifier. In theory you can get about 10W into 8 Ohms, but there is some voltage drop across the transistor/MOSFET and you can't actually get the full power supply voltage across the speaker.High power automotive amplifiers have a voltage-boosting power supply.
wow that's a lot of sources quick, thanks guys! I'll take a look at em now. @retrolefty and DVDdoug: I meant put the speakers in parallel, not the amps, so I can drive more power at the same voltage. However since class D amps are 'digital' I figure they are a bit harder to predict how they will behave outside of thier rated range of loads compared to AB amps. Gotta dig into the datasheets to konw for sure. stupid low voltage supply, BUT since it is so close to automotive range, I know there must be devices out there specifically for it.
Power needs are still up in the air, but probably on hte order of 5W.
The catch is since it is battery powered, I want to stick with a single +13v supply to keep things simple and not have a neg source eating up power.