A:Answer Hello. Without knowing which make and model speaker you have, it is not possible to be sure. The wattage rating of a speaker is often just the manufacturer saying 'for use with an amplifier rated at no higher than 150 watts RMS'.
The AVR-X1800H can drive a wide range of speakers, but there are a number of factors to consider with any amplifier/speaker pairing, including speaker sensitivity rating, impedance, room size, how loud you may want to take the volume levels - to name a few.