Somewhere around the end of 1989, my beloved Commodore 64 was start to get long in the tooth and I was looking at upgrading to what all the cool kids (geeks) were getting, a Commodore Amiga 500. I remember that there was none to be had up on the Sunshine Coast where my family was living at the time so my brother Stephen, drove me down to K-Mart at either Strathpine or Toombul.
My new Amiga 500 set me back $600 and I also got an extra floppy drive and a new printer. I can’t imagine how many times I printed out the assembly code for my music driver and demos. I’d print them and then pour over them for hours trying to figure out how to optimise my routines by cycle-counting every instruction – not that your had to worry about that so much on the Commodore Amiga. Doing this was largely a throwback to my C64 music days.
[warning]Very Wide Stereo Separation
These are raw recordings and not entirely headphone friendly. The Commodore Amiga sent its audio channels completely to either the left or right speaker. May sound disorienting through headphones.[/warning]
Gilder Rider (C64 Remake)
When I got my music driver into a workable state, I didn’t have the patience to write a bit of music to test it out. Instead, I made a version of David Whittaker‘s “Glider Rider” while I was programming the driver. A bit of machine code hear then add a bit of music there and so forth.
I wrote this one when I was going to Tafe to study IT. It ended up being used in a demo by the demo group I was in at the time, Factor Four.
On the Inside
This music was very ambitious for me at the time and it’s still a piece that I go back to once in a blue moon. It ended up in some demo – I’ve got no idea what that demo is any more.
Well this was a surprise find from a bit of Googling. I did have a vague recollection of my Commodore Amiga sound driver being able to generate simple waveforms in realtime. These waveforms mimicked the triangle, sawtooth and pulse (with variable width) waveforms of the C64 but as soon as I loaded this intro in FS-UAE, it all came back to me how far I got with real-time waveform generation. Well, I remember a lot more but not all really.
The Commodore Amiga had a simple low-pass filter (even simpler than that of the C64) that you enabled and the power light on your computer would switch off to signify that the filter is on(?) and that the filter affected all sound channels equally. After the love/hate relationship us C64 musicians had with the C64’s filter, I embarked on creating my own filter that I could apply in real-time in different proportions on individual sound channels.
This is where my memory is still a little sketchy but from memory, I think I wrote some kind of additive waverform generator that modified the base triangle, sawtooth & pulse waveforms much like you’d find in FM synthesis.
You can hear the C64-like sounds and the filtered affect in this remake of the original C64 intro music.