You might generally have more trouble with room tuning in a big empty room without a lot of furniture. I have my system integrated into a larger apartment room with a lot of stuff everywhere. (couch, recliner, blankets, rug, etc.) I've almost never heard "too harsh." (unless you want to put in a really old movie and crank that up)
It's amazing what the difference is between a properly powered speaker like the m80 is at high volumes and other systems not built for full volumes. Like say turning your tv speakers up to max, blech... our neighbor does this. Also lots of restaurants that play music by turning up boom box speakers really loud, ouch.
It seems like often the parts of the higher volumes you can't stand are the distortion, the clipping, case rattle and overall shrillness. On the flip side, if your amp and rig can keep up with big dynamic changes.. wow. I find movies have the power to startle me more now. Jumping from dialogue to full explosions or a window shattering, etc. It's pretty amazing.
