Spectrum Music like Earth Shaker

Welcome to the 1-bit forum! Great to have you aboard.

Very happy to hear those unreleased 1-bit tracks! The tracker conversions are excellent as well. I'm not much of a gamer myself, but I think some people would go nuts if World Shaker ZX was to be released one day. Seems the PC version was never widely distributed either?

Also, how did you compose the music back in the day, actually? Did you hard-code it all in asm?

how did I compose the music - hmmm yeah I just used to put in in as numbers in READ and DATA statements (and still do in fact whenever I use that routine). I had a list of frequencies blu-tacked on the wall, or maybe on the Galaxians arcade cabinet that used to take up half of my bedroom. I wrote the whole of Earth Shaker like that, just poking in numbers I'd looked up in the back of the Spectrum manual when I worked at Zeppelin a couple of the guys there took pity and gave me an assembler.
The Earth Shaker tune was obviously a bit influenced by the one in Arc of Yesod, which I loved. I remember trying to only use chords and notes which sounded good played by the routine, as some verged on the grindy Manic Miner chords. I noticed that mathematically pairs of numbers which are coprime (have no common factors) often generate the best chords because the chord then lasts longer before it repeats. You could even make it sound like triplets if the frequency repeated at the right interval, which I used at the end of one of the sections.
Wouldn't hold your breath for a World Shaker ZX release though - it's something I would love to do but realistically with a full time job, two daughters and all the other million things I do I'll pencil in a tentative July 2045!