How Distortion Works in Music
One kind of distortion that I loved to apply in my FastTracker II days, and which I don't see used all that often, is to flip the sign.In short, FT2's sample editor could handle a few common waveform formats, but this was cross platform days and there were a lot of wave formats. These have differnt headers and different structures, but many of them ended up being just a series of samples, either in 8-bit or 16-bit, and at some sample frequency. To deal with this, FT2 added a button that let you reinterpret a waveform as if it was stored signed or unsigned, and one that let you reinterpret as 8/16 bit. This let it load a huge amount of sample formats well enough; you'd fiddle around with those buttons until it sounded right, then you cut the first few millisecs of noise (the file format header) off the front, and done!But turns out that the "reinterpret as (un)signed" button (called "Conv" in FT2) is pretty spectacular for nasty distortion too.Imagine a sine wave. Loaded correctly, it'll look like this:     +-----------------------------------------------------------------------------+
     |                                                                             |
     |                                                                            X|
     |                  XXXXX                                                   XXX|
     |               X       XX                                                X   |
     |              X          XX                                            XX    |
     |                                                                      X      |
     |           X               XX                                        XX      |
     |                             X                                      X        |
     |         X                   X                                    X          |
     |                              X                                 XX           |
     +-----------------------------------------------------------------------------+
     |      X                        X                              X              |
     |     X                          X                            X               |
     |    X                           X                           X                |
     |                                 X                        XX                 |
     |   X                             XX                      X                   |
     |                                  X                    X                     |
     |  X                                X                 X                       |
     | X                                 XX            X XX                        |
     | X                                  XXXXXX X  XXX                            |
     |                                                                             |
     +-----------------------------------------------------------------------------+


Imagine this was stored as 8-bit signed. Now, if you reinterpret those bytes as unsigned, it'll look like this:     +-----------------------------------------------------------------------------+
     |      XX                      XX                              XX             |
     |     X X                      X X                            X X             |
     |    X  X                      X X                           X  X             |
     |       X                      X  X                        XX   X             |
     |   X   X                      X  XX                      X     X             |
     |       X                      X   X                    X       X             |
     |  X    X                      X    X                 X         X             |
     | X     X                      X    XX            X XX          X             |
     | X     X                      X     XXXXXX X  XXX              X             |
     |       X                      X                                X             |
     +-----------------------------------------------------------------------------+
     |       X                      X                                X             |
     |       X                      X                                X            X|
     |       X          XXXXX       X                                X          XXX|
     |       X       X       XX     X                                X         X   |
     |       X      X          XX   X                                X       XX    |
     |       X                      X                                X      X      |
     |       X   X               XX X                                X     XX      |
     |       X                     XX                                X    X        |
     |       X X                   XX                                X  X          |
     |       X                      X                                XXX           |
     +-----------------------------------------------------------------------------+

Notice how the top half and the bottom half of the sine waves are swapped.Now, I don't understand much about DSP and sound and the frequency domain. Better programmers than me have told me that this makes no sense from an audio/music perspective. But it sounds pretty cool; you keep a lot of the essence of the original sound, and add a lot of nasty.I once made a VST plugin that does this (it lets you slide the waveform up, wrapping over to the bottom; its only parameter is by how much to slide), but I don't think I have it anymore unfortunately.For context, applied to a random bassdrum using 8bitbubsy's amazing Windows clone of FT2[0]:- original: http://neuvostoliitto.nl/808_drum_kick_035_21338.wav- distorted: http://neuvostoliitto.nl/808_drum_kick_fucked.wavJust sharin' :-)[0] https://16-bits.org/ft2.php