5.20.2013

YM2612 "LADDER EFFECT"

When I was working on this side of things for the FMDrive Vsti, I have made of bunch of testing on the hardware.
Here is a possible approach of  the YM2612 chip "Ladder effect" on the DAC side.
Further informations could be accessed on the web.

when setting the output of a channel to "mute"
REG B4H LEFT&RIGHT bit==0;
Playing some notes here do not play silence but the same line as normal except (center) already distorted from the start and at a lower volume.
The very last ms ends with quantized effect on top of that.
TL as almost no effect on the slot until near max attenuation.

I think that the distorted line and the clean line simply adds together from the start.
The fact that we only ear the last portion is obviously because, as the clean line reaches low volume, the frequency richer distorted part underneath become prominent and that is also why some sounds seems to have a longer tail on the hardware then on clean emulation.
The positive portion of the sine also seems to be slightly shifted to the right the more the attenuation goes.
So there might be something in here just before MOL and MOR...
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Here is a wave recording of the effect.
1// B4 D7 and D6 are set (center)
2// (mute)

LADDER EFFECT 

This is basically how I have emulated the process in a clean simple explanation.


FMDrive Vsti Music Examples

Here is some Weekly demos made with FMDrive Vsti.

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NINJA STEP 
composed by Yuzo Koshiro
from Revenge of Shinobi soundtrack
PAL version

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FMDrive in HD mode. and a little mixed and arranged.
ninja-step-pal-on-fmdrive-vst 

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THUNDER ZONE
composed by Aly James
Tribute to Thunder Force III soundtrack
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FMDrive in M1 mode.
thunder-zone

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GLITCHES BREW
composed by Aly James
Tribute to Miles concept...
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FMDrive in M1 mode.
glitches-brew

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FMDrive AUDIO COMPARISON
composed by Aly James
Same track 1/Hardware,2/MD1 mode,3/HD mode...
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PAL Megadrive Model 1.
FMDrive in M1/ HD mode.
 fmdrive-vst-demo-01

5.08.2013

YM2612 CSM MODE INFOS

This is a practical overview of the CSM mode (speech synthesis) found in the YM2612 chip features.
The YM2612 chip is the sound heart of the SEGA Megadrive Console.
These informations could be useful to anybody planning to integrate CSM feature control on the hardware or emulator.
My FMDRIVE Vsti benefit of a special implementation quickly explained here.

 
FMDRIVE Vsti synth is available at alyjameslab.com