What Doug means here is that if the amp or speaker isn't having to work at the limit, then you are probably all right. Indeed, if he never drives it that hard, it doesn't matter, BUT if he ever DID, it really does. I rely on my ears to tell me something is in gack land, and THEN look to the amp and mixer clip lights to tell me what I need to know. If I set up my system in advance, and have tested it, though, I pretty much know where the limits are, anyway. And I've only seen one failed clip light in my 27 years in this biz.
ANY distortion is undesirable.
Training yourself to hear and respond to a clean signal is the best way. And I agree that having taken care of that up front makes the whole event much more relaxing and worry free. All Rights Reserved.