What does clipping sound like?


I have been wondering if the break up distortion I hear with my 60 watt tube amps is because I have insufficient power for my 91db 6 ohm minimal speakers. I do question if that rating of my speakers is correct.
When the music swells, I get break up sound. It is not on low notes or high volume. I do wonder how my speakers would perform with a lot more power. I have always thought that any speaker likes more power.
mglik
+1 for preamp overload of low level signal input. It would be interesting to know if it occurs from a specific selected or all source inputs to the preamp.
If you play your system loud, it doesn't take long to eat up 60 watts. If you turn your system down, does it get better? 
It’s not clipping if no correlation with turning up the volume. Something else then that would have to be isolated by testing one change at a time.