"BP" wrote in message

Would 680 watts into 4 ohms be too much for this unit in a large room?

If you try to use 680 watts with these speakers, it's easy to predict that
you're going to blow the tweeter fuses - they are only 3 amps will blow
someplace around 36 watts continuous power. The speakers are not that
efficient, and the tweeters are crossed over pretty low (500 Hz).