the room size is needed.
the sub listed is not that great.
if the speakers are trying o fill in what it cant, it will have issues.
The room size is not needed when asking if his amp is not powerful enough to run his speakers. All that we need to answer that question is the RMS rating output of the receiver and the RMS ratings of the speakers.
He specifically stated distortion. Playing them too loud could cause this. Or there could be another problem BUT his question was is his receiver powerful enough for his speakers and it is powerful enough.
I understand what you are getting at; you think he might be in a very large space and his system just doesn't have the power to fill it but that really has nothing to do with his original question. That is indeed another possible issue but it's not needed to answer his question.
I can take one of my amps, a couple of speakers and place them in my warehouse...sure they won't fill the space but they will get loud and not distort.
If he is cranking up the volume to fill a large space then it should still sound good until he reaches that point where the amp clips or the speakers are over-driven. It would sound good up to that point. We don't know how loud he is trying to play them. Again though he only asked the one question in his original post which I answered above.
His next question in his other post asked why his friends Bose sound clear and loud while his speakers distort. I'd have to know if those Bose were brought to his home and hooked up to his amp or if he just heard them at his friends house. That would give us more info to go on. I was under the impression his friend hooked up two bose to the receiver in question and it sounded great. That implies that something is not right with one or more of his speakers? or his speakers just don't sound good? or the Bose are just better? Who knows.
It could be just a matter of setting the speaker frequencies up properly for each speaker and not cranking the gain on the sub. He doesn't get specific enough about what is distorting, at what point does the distortion occur or anything else.
But the one question he asked that is easy to answer was answered already above. Yes his amp is powerful enough for his speakers.