New Online MSX emulator

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By tvalenca

Paladin (728)

Аватар пользователя tvalenca

04-03-2016, 19:17

JohnHassink wrote:

Well, they sure stripped that OPL2 down to create the OPLL. Less (or cheaper) chips 'n' transistors etc. needed. For instance, instruments went from having 4 operators to 'only' 2. So it probably really mattered in mass-producing the thing. Sometimes, business executives make steep decisions, I guess. Smile

I thought OPL2 only had 2 operators. (by operators, are you talking about waveform generator? If yes, I thought OPL2 and OPLL had 2 waveforms, and OPL1 and MSX-Audio Chip -Y8950- Had only one.)

By anonymous

incognito ergo sum (109)

Аватар пользователя anonymous

04-03-2016, 19:29

@ tvalenca: I think you're right. Only two oscillators for both OPL2 and OPLL. It's the amount of waveforms that got reduced to two (instead of three?), and no doubling for mixing the channels anymore. And the DAC for playing all channels in a row through an analogue filter. That's pretty much how far my technical understanding goes. Wink
I'm by far not an expert on chips, nor am I a true "chiptune composer". I'm just a guy who likes to compose music and knows a little bit how to get certain sounds out of certain chips. Smile

By sd_snatcher

Prophet (3261)

Аватар пользователя sd_snatcher

04-03-2016, 23:35

Whoa! Operators and waveforms are different beasts. Smile

Operators are the essence of the FM synthesis. They can be combined in different algorithms to affect the output of the other operators of the same set. The more operators you have in a given set, the more complex is the resulting timbre.

Waveforms on OPLs are exactly as the SCC waveforms, except that unfortunately they are in ROM and can't be user-defined like in the latter. If they could be written we would have had a hell of soundchip that would join the best of the FM and SCC universes.

Waveforms were an ingenious idea to produce more complex resulting timbres that would otherwise require a lot more operators to achieve the same result. This is why I can't agree with whoever looks down of the OPLn family for having less operators than other FM soundchip, while they ignore the fact that those chips have only a fixed sine waveform.

Here's a summary of some Yamaha FM soundchips listed with their number of operators and waveforms:

  • YM3512 (OPL1): 9 channels, 2 operators/ch, 1 waveform
  • Y8950 (MSX-Audio): OPL1, +1ch ADPCM
  • YM3812 (OPL2): 9 channels, 2 operators/ch, 4 waveforms
  • YM2413 (OPLL): 9 channels, 2 operators/ch, 2 waveforms
  • YMF262 (OPL3): 18 channels, 4 operators/ch, 8 waveforms
  • YMF278 (OPL4): OPL3, +24 PCM channels
  • YM2151 (OPM): 8 channels, 4 operators/ch, 1 waveform
  • YM2164 (OPP): 8 channels, 4 operators/ch, 1 waveform
  • YM2203 (OPN): 3 FM channels, 4 operators/ch, 1 waveform, +PSG
  • YM2608 (OPNA): 6 FM channels, 4 operators/ch, 1 waveform, +PSG, +1ch ADPCM, +6ch ADPCM percussion
  • YM2612 (OPN2): 6 FM channels, 4 operators/ch, 1 waveform

IOW, with 8 waveforms and 4 operators the OPL3 can create quite some complex FM instruments. Too sad, very few software ever used that potential. One of the few I know are:

But enough with the derailing of the topic. I don't want to hijack the thread. :)

By ppeccin

Champion (374)

Аватар пользователя ppeccin

17-03-2016, 16:35

Hey guys!

Does anyone know of any good documentation about the MSX MUSIC BASIC commands? I only found this, but its insufficient:
https://www.msx.org/wiki/MSX-Music_programming

It would help me a lot to test my implementation.
Specially I can't figure out how to send drums commands to play in basic.

Thanks

By Grauw

Ascended (8927)

Аватар пользователя Grauw

17-03-2016, 18:01

http://msx.hansotten.com/uploads/msxdocs/fmpacpanacart.txt

I was also looking for the FM-PAC manual scans, but couldn't find it, anyway if you can then it also contains a description of the Basic commands iirc.

By ppeccin

Champion (374)

Аватар пользователя ppeccin

17-03-2016, 18:35

I can't understand the relation between the MUSIC and PLAY parameters. Its SO confusing.
Can someone give an example that plays one drum sound?

Thanks

By NYYRIKKI

Enlighted (5508)

Аватар пользователя NYYRIKKI

17-03-2016, 18:42

Drum example:
CALL MUSIC: PLAY#2,"","","","t220b8h8c8h!8"

... try also the example on Wiki-page. At least I like it a lot Smile

By ppeccin

Champion (374)

Аватар пользователя ppeccin

17-03-2016, 18:51

Ok, it worked.
Some questions... Why are the drum commands in the 4th String passed to PLAY? Is it aways that way?
Can we somehow control the tone or pitch of the drum sounds? Like different TOM notes?

By NYYRIKKI

Enlighted (5508)

Аватар пользователя NYYRIKKI

17-03-2016, 19:04

4th parameter is the default drum channel, but you can change that with CALL MUSIC command. Drum channel is always the last one. ie if you want it to be 7th parameter, you can use command:
CALL MUSIC (1,0,1,1,1,1,1,1)

(Yes, pretty confusing, I agree)

By ppeccin

Champion (374)

Аватар пользователя ppeccin

17-03-2016, 19:04

Oh I see...
What about the tone control of drum sounds? Is that possible?

As I hear it, the drum sounds in games are very different from those I get in BASIC.
I hope the fixed drum sounds of the chip are not unchangeable and ugly like those from BASIC.
(not considering the ONE custom sound)

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