Our amplifiers are Loud and Clear. We have 2 channel amps and 4 channel amps
2 channel amps are made for 2 speakers, one amp will power 4 speakers, but it divides the output into each speaker, making it not as loud. we have several customers that use one amp to power 4 speakers and are very happy with the setup. you could always add an additional amplifier if you wanted to later, that would be a 3.5mm splitter to split the output of your audio device to each amplifier, then you'd have one amp powering the 4" chrome speakers, and another amplifier powering the 6x9 speakers
we do have 4 channel amps, that will power 4 speakers with no loss to any of the speaker.