| Fun Fact: Why is AC/DC nearly all power chords and Major Chords? short answer: it sounds good long answer: extra notes are added. At some point during guitar history, some metal head was like "I wonder what happens if I turn this tube amplifier up ALL THE WAY to 11?" and... it sounded "good". Nobody really knew why at the time, but this distorted electric guitar was like, pleasing to the ear. Sometime later, we figured out the science of why, after many many models of tube amplifiers had been designed and tinkered with. It turns out that since electrons, are in fact waves, they can interfere with each other. As they blast across the space/time in a vacuum tube, they can interfere with each other... and if they are modulated in such way, let's say by a musical input, they happen to produce "interference bands" in a certain predictable manner as a function of the input signal. What does that interference banding look like? Extra notes! Yep, when you slam a powerchord root-fifth at max distortion on a single-ended amplifier (the input stage to a Marshall), you produce "even order harmonics"! If you rip A+E you'll get: * Original A (root)
* Original E (fifth)
* Octave A (very forward, usually -1.5db)
* Octave E (very forward, usually -1.5db)
* 12th above the root (Another "5th"!) (Not as forward, but audible, -2.5dbish)
* C# two octaves up (3rd) (Making this a major chord!) (Not as forward, but audible, -2.5dbish)
* G two octaves up (Minor 7th) (Not as forward, but audible, -2.5dbish) Whoah!? And the pattern continues but at some point amps filter out the series. And guitar amplifier dudes also figured out how to make all kinds of distortion sound crazy! A 5150 produces "odd order" harmonics and makes adds totally different content. The pre-amp and the power amp sections interfere with each other, making the output function deterministic, but super complicated! I used to think people were just being snob-ish about tube amps until I really dove into making my own guitar amp design. It's a crazy clash of music theory, functional harmony, and analog electrical engineering! |