Commander X16

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There are 2 designs in final testing and one or both will remain:

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  Yamaha YM2151 sound chip
  


• 
  SID-like implementation in the VERA FPGA chip
  

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• 
  16-channel stereo Programmable Sound Generator with multiple waveforms (Pulse, Sawtooth, Triangle, Noise)
  

7 minutes ago, John Chow Seymour said:

So.. the PSG is the "SID-like implementation", or are we getting that PSG and also one of the other options (TBD)?

13 minutes ago, John Chow Seymour said:

In that case, I hope they find that it's possible to go with both the YM2151 and the VERA PSG.  As kliepatsch said earlier, they would complement each other well.

1 hour ago, John Chow Seymour said:

In that case, I hope they find that it's possible to go with both the YM2151 and the VERA PSG.  As kliepatsch said earlier, they would complement each other well.

On 6/14/2021 at 9:44 PM, ZeroByte said:

The YM2151 can really do some interesting things if you go "off-script" with it. For instance, the KeyON register has an interesting way of gating notes. Instead of a single gate for each voice, you can gate the 4 operators individually. This means that if you're clever with the ADSR values of the 4 operators, you could make a sound that features a continuous tone but with a cyclic modulation - so something that kind of goes WooWooWooWooWooWoo... - It's hard to describe this in text, but I'll give it a stab. (I'd have to make a program to demonstrate this as your typical tracker / OPM DAW plugin isn't going to offer this function either). Suppose your tone-generating operators have a D2R of zero - meaning that once the envelope reaches the sustain level, it will not decay anymore until you gate in a release on the voice. You start your sound by triggering all 4 operators.



e.g.: let's say operator 0 is the modulating operator



Now let's say one of your modulating operators does have a full ADSR with a D2R so the modulation runs its course.  Say the sound goes like oooOOOAAAAOOooo  (and stays "oooo" thereafter). You can re-trigger only that one operator and get another cycle of the effect w/o the sound ever decreasing its volume. So if you have some sound effect that represents something like a plasma beam firing, or a UFO engine, or something like that, you can just keep re-triggering the modulating operator to generate the effect.



Maybe I should try whipping something up in BASIC as a demo and do a "how-to" video on it or something.

2 hours ago, a9m said:

Let me explain this. Basically you can start and re-start envelopes independently on each operator. Depending on how you set up connections you can either do echos or crude LFO without restarting the main carrier's envelope.

On 6/15/2021 at 1:16 PM, a9m said:

Let me explain this. Basically you can start and re-start envelopes independently on each operator. Depending on how you set up connections you can either do echos or crude LFO without restarting the main carrier's envelope.