I recently bought a wireless system and noticed something that maybe someone can explain why it's happening. I normally play at bedroom volumes and noticed that, playing with a lot of gain, standing close to the amp and standing further away really makes a difference in tone. I noticed that when I'm about 2-5ft away it sounds great, but when I starting walking about 15ft or more away it sounds as though the top end starts to disappear leaving a hollow/bassy/muffled kind of sound. If I turn up the presence and treble it starts to sound good again, but then I also have to raise the volume. I'm guessing this is a normal and there's some kind of scientific explanation for this. But, I never realized that distance can make such a difference. I also noticed that clean sounds don't suffer as much at different distances. I tried searching for this type of topic but nothing came up and I thought it interesting.