MATRIXSYNTH: Kawai K3m ROM Mod


Wednesday, April 11, 2007

Kawai K3m ROM Mod

Plutoniq9 (Ryan) sent the following to AH. I asked him if I could put up a post and he gave the thumbs up.

"Just a recording demo of a Kawai K3 with a TB-303 waveform (Replaced in ROM).....thanks to a list member for supplying the raw VCO square/sawtooth recordings. Not bad, considering they needed to be converted to 8-bit @ 22khz.

k3m_303_saw.mp3 (3.3M)

Prophecy is providing the arpeggio (via midi) to the K3m. I'm still not sure if I'm gonna bother with bandlimiting yet, maybe in the long run....... but the Prophet-VS I know gets part of it's character from it's aliasing & they only cause real problems in the highest octaves. It was a pain in the ass getting this far :)"

I asked Ryan if he had a web site or page up with more info and he said one would be coming on audiosyn.com.

"I'm actually still working on waveform selection, my plan is to create a ROM bank thats 50% classic analogue waveforms and 50% digital, mainly some good Prophet-VS samples + choir & strings on the digital side (basically, all the things that the K3 sucked at).

The ROM system is very cryptic :) Interleaved waveform data (containing different octaves) + a second ROM containing information necessary for anti-aliasing the waveforms (also interleaved). The service manual does not even brush upon this area, so it's been heaps of trial n' error getting it to work right. I've got some rudimentry code that allows me at this point to encode 512-byte raw waveforms (8-bit @ 22khz), but with no bandlimiting (at the moment).

Hopefully I'll have a ROM available shortly (freeware) for download, though I'm still holding out for some better analog waveform samples. Additive potion of the synth is not touched, and there will be a way to switch back to the original waveform set (or an additional bank of 31 waveforms)."

Thanks Ryan!

10 comments:

  1. The 50% bandlimiting is pretty important though, since it's used as a sort of cheap (although insufficient) alternative to interpolation. Leaving it out will cause the oscillators to alias even more than they already do with the factory waves.

    I wish the K3m used a higher sample rate for its' oscillators.

    ReplyDelete
  2. Awesome! It is a nice synth, but it could be a great synth with some better waveforms. My K3 has been for sale for quite a while, but it's one of those synths that I wouldn't mind keeping if nobody ever wants to buy it.

    ReplyDelete
  3. well the links goes nowhere...

    How can we replace ROM waveform? is it an EPROM ? ROM are not writable...

    ReplyDelete
  4. so, would the same thing be possible with the k4 and xd5?

    ReplyDelete
  5. Mp3 link is fixed. Sorry about that. Title link just goes back to the post.

    ReplyDelete
  6. Samples, waveforms and operating system code on most synths from the eighties and early nineties reside on EPROMs. It's relatively easy to reprogram and change the chips yourself if you have an EPROM burner. The hard part (as with the Kawai K3m) is figuring out just what sort of data the device needs.

    ReplyDelete
  7. Very cool. I have a few K3's and woul d like to get any information about this and any other mods that might be possible:

    Detune oscillators in mono mode?

    Sync LFO to midi clock?

    Also, this was posted in April - anything new since then?

    - Joel

    ReplyDelete
  8. wow, your a genius- i dont really understand how your doing it, but please post on the yahoo k3 group when you can get those rom banks working - cuz the factory ones suck

    http://launch.groups.yahoo.com/group/K3Resurrection/

    ReplyDelete

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