Playing Led Zeppelin On A C64


In the C64 demoscene there are a ton of awesome software hacks that push the Commodore 64, the 1MHz 6510-based computer from 1982, to its limits. Most of these C64 demos are very much limited by the hardware inside the C64, but the demoscene is always coming up with new ways of pushing the envelope. [No Quarter] just sent in one of these software hacks that propel the capabilities of the C64 into the realm of absurdity by playing full length songs directly from the floppy drive.

Playing a song on the C64 begins with an Amiga and a Perfect Sound digitizer to convert the digital audio file into a 4-bit sample. Once this sample is transferred over to the C64 where it was manually timed so streaming it off a 1581 disk drive would result in the song playing at the correct pitch. It’s an amazing work of optimization; the audio data is streamed off the disk just as fast as it’s played from memory, an amazing data throughput rate for the ‘ol C64

After the break you can see [No Quarter] playing Led Zeppelin, Bon Jovi, Shania Twain, and Extreme. A very, very cool project and with the addition of a C64 hard drive makes it possible to have a media player for the C64.


24 thoughts on “Playing Led Zeppelin On A C64

    1. The 1541 drives were hacked together at the last minute, they actually have the same processor as the C64 which was used to bitbang data over the cable at a suboptimal rate. I suspect that’s why the 1581 was used for this hack, it’s still impressive to interleave constant disk access with continuous sample playback on this machine.

      One of the thinks I love about 8 bit ‘puters is the restriction of hardware remains the same, yet demoscene coders and hackers can do more and more with it, by utilising modern computer science advances to help build code. I’d love a time machine to go back to 1982 with a stack of demo disks, red storm, mayhem in monsterland, c64annabault, Dallas FMV demo etc. it would be seen as magic to them!

      1. Not exactly the same processor. The 1541 used a 6502. The C64 actually uses a 6510. That’s based on the 6502 with extras. The 1541 is a computer in it’s own right and gutting one is a great basis for your own 6502 computer build projects.

  1. nice one… I remember the good ol’ days when I used C64 as an amplifier for my bass guitar. Plugged it into C64 audio in (yes, it has one pin that acts as audio input), doing a POKE somenumber,15 to set the volume to max, and cranking the old tv all the way up, and it worked

    1. The 1541 can’t keep up and we never owned a 1571 drive. This pushed the C64 to its absolute limits as the 1581 can just barely keep up. Back then, any time there was disk access, the whole computer froze up. Sure the audio sounds crappy, but this is an 8 bit machine running at 1MHz. In order to stream it, you have to compromise on the audio quality so the computer never stops and waits to load in more data. This is the best you could do back then.

        1. That’s pretty darn cool that it can stream from a 1541!!! I gotta hear this to believe it. I guess since my brother did his hack in the mid-90s, he can at least say he did it first. :)

  2. Yeaaaaaaa, this is way cool. I’ve always wanted to do some streaming audio like this for the SNES.

    Gotta disagree with the guy that said “play still alive from portal!”. good god has that song been beaten to death in these types of videos! no more! please!

      1. In that case, should play the Bad Examples then:

        I was born too late to play in the rolling stones
        I don’t know jimmy page,
        I never met yoko ono
        Standing with a strat,
        I’m rock and roll’s bastard son
        Go out, get drunk, get laid, have fun
        I don’t got a million dollars,
        don’t drive a cadillac
        Gimme half a chance, ’cause I’m not dead yet

        I’m not dead yet – not dead yet
        I’m a mad dog fighting with the wall against my back
        You’d better get a bigger gun,
        I’m not dead yet

        I been machine-gunned, hand-gunned, hijacked, left for dead
        Divebombed, napalmed, nuclear warheaded
        Dropped from a jet plane with no parachute
        Shot by a firing squad and raped by a business suit
        I’m dancing on a landmine, one leg left
        But I can still crawl and I’m not dead yet


    1. Actually the Atari 8-bit had a demo that played and recorded audio digitally using the analog inputs from the paddle controllers as A/D converter.

      BTW My Atari ST is sitting next to me running star glider intro (that has a digitized sound intro)

      The 8-bit Atari’s had some hardware advantages over the C64 (6502C @ 1.79 MHz and some specialized hardware such as the GTIA and POKEY chipset) so it’s not nearly as difficult as getting a C64 to do the same thing.

  3. Hey guys. I submitted this hack this morning to It’s my brother’s handiwork. It was never released and as present is packed away in a closet somewhere. Just to correct the hackaday information, this is NOT playing from a hard drive. This is playing from a 1581 floppy drive. I’ll email them about making the correction.

    1. None of it is. It’s got a static sound to it because this was about the best you could by rapidly changing the volume of the SID chip to play a rudimentary digitized sample. The C64 was never designed to play digitized samples and so it was a hack that worked although very primitive. Most of the samples you hear in songs are short and looped. Other demos would play a short 5 to 20 second sample because that’s all memory could hold! So this hack involves a custom load routine to shuttle the data as fast as possible and then it’s playing it at the same time it’s loading. The audio quality was beside the point when you were pushing the hardware to play a full-length song from the floppy.

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