I Love your music subject, because I am a Metal fan myself.
Heavy Metal came from the Blues area when a blues band got a flat tire and along with it, came down the amplifier. The amplifier got hit hard. They agreed to take a look at the problem in the studio, but when they tested in on the guitar, the guitarist loved it's sound. Until seberal years later came the Fuzz Pedals and Overdrive Pedals leading to everyone from AC/DC, Jimi Hendrix, Led Zeppelin, Johnny B. Goode and more bands until Distortion Pedals we're invented. Distortion (in Guitar as a setting) has a rougher, raw-er and gnarly sound than Overdrive, Leading to bands like Def Leppard, Tygers of Pan Tang, Iron Maiden, Mötorhead, etc. These British Heavy Metal bands gave birth to bands like Dio, who kept their Heavy Metal sound; Metallica who went for a mix of Heavy and Thrash Metal; Pantera from Glam Metal to Groove Metal; Slayer to Thrash/Death Metal, and; Rage against the Machine and System of a Down to Alternative/Nu Metal.
Turkish march (rondo alla turca) by mozart should be played at 126 BPM