I think Jonas is after the decrunching sound (depacking data sent to the sid) that occurs before a lot of crack intros start.
I recommend using a decent C64 emulator (like VICE), download a couple of cracks (e.g. [CSDb] - The Commodore 64 Scene Database) and sample the output. VICE offers a possibility to save the audio output to .wav aswell, I think.
There were so many crunchers back then at the time.
Not everything made noise either. Some only showed colourfull flashy raster bars.
There are a batchload of c64 demo’s that also decrunched in between parts, i guess you could inspect a lot of those too.
decrunching is not really an interesting process to make millions of dedicated video’s for it and i guess most folks even remove the decrunching part completely as it’s not interesting to share.
A500 only had the DD 880kB drive didn’t it? If I remember the 1MB upgrade gave you a total of 1.5MB as it was on top of the RAM installed by standard, although may be wrong. Wiki seems to say I’m wrong “# The Chip RAM can be upgraded to 1 MB directly on the motherboard” Suppose it depends how much memory the Protracker software itself took up…
You could simply add more RAM to your chipmemory area by soldering a junction on the motherboard. I am also not sure wether this could be raised above 1MB though, i had 512K chipmem and 1MB fastram, i thought i could add them all up.
But then these spaceballs bastards came and released their cool “State of the art” demo that didn’t wanted to run on an A500 having over 512KB of memory. So for this demo i had soldered a switch to this junction so i could either switch to 1,5MB chipmem or 512KB chipmem.
Hmmm… since I had several TV’s while i had my C64 I always thought that these noises when something was decrunching were caused by the the TV itself, because they always sound different. I guessed it was caused by the very fast changing colours… But maybe I am wrong…
From the back of my head as i understood it back over 20 years ago (so it could be poluted by a high percentage of belony right now, apologize in advance)
The C64 has several banks covering addresses from 0000 to ffff (65535). More or less one could change banks and swap data so one part of the memory was actively doing something and the other part was only being filled with data to be started up later.
There were some magical addresses in the $Dxxx range to set and change specific registers for various control areas of the C64, Like the 6501 amongst others and the 6581 was also one of them who had to be controlled by registers.
But sometimes these addresses weren’t used for the purpose they were invented for but got abused by other routines to allow them performing jobs completely unrelated to the task these addresses were meant to cover, hence if some decruncher was doing some fancy stuff by abusing banks and addresses used to configura stuff for the 6581, you heard noises as a side effect as the 6581 ofcourse responded to the data that got send to it in the crossfire.