Ok, well I can't set anything.
I am using B&W 802D speakers, rated at 8 ohms and 4 ohms for the woofers. I am also using a McIntosh integrated amp rated at 100wpc 8 ohms, 150wpc 4 ohms. As I said, I cannot switch anything anywhere, So my question was related to exactly what happens if the amp is rated at 8 ohms and 4 ohms but there is no switch or any way of changing the impedance. Does the speaker just draw using the impedance for each speaker as need be?
The reason I am asking is because I am about to upgrade to a higher power amp. I have been considering going with either a 300wpc or a 450wpc McIntosh but each has only one power rating at 16, 8, or 4 ohms (300wpc and 450wpc), or going with a different amp altogether which is rated at 325wpc into 8 ohms and 500wpc into 4 ohms. Might this amp be a better way to go considering the woofers are rated at 4 ohms? Would the amp supply 500wpc into those woofers while supplying 325wpc into the mid and tweeters?