Hi,

I'm just curious about the way the SCC works.
What is the purpose of the 32 bytes waveform table per channel ?

Is it a table to define an ADSR envelope ?
That would imply that the SCC has only one fixed sound operator per channel.

Or is it a table to define the sound itself ?

It's the waveform of the oscillator, so to say. Just like a classic synth would have an oscillator in the shape of a sawtooth or square. And the normal SCC has 4x 32bytes for 5 channels. chan5 shares its wave with chan4. The SCC+ (Snatcher, SD-Snatcher) has really 5 intrinsic waveforms.

It's not clear ... For me the classic synth works like this :

1 - a sound generator produces a chosen waveform (square, sawtooth, ...)
2 - then the chosen ADSR envelope monitors the volume evolution of the sound produced

In the case of the PSG, for example, the sound generator cannot be changed, and the ADSR envelopes can only be chosen among a pre-defined list.

From the info found on the net, I would believe that the SCC has also a sound generator that cannot be changed (that is why all the sounds generated are quite similar), but that the ADSR envelope is defined by the user through the 32 byte waveform table.

However, the MSX-Music gives the user a (limited) choice of sound generators, which means that the sounds can really be different. I don't know about the ADSR envelope choices, though.

No,

The user can upload 4x 32 bytes of wavememory to the traditional SCC chip, these waveforms can be anything.. from a simple sawtooth to complete chaos. In essence, it's just like a sample playback device, where the samples are max 32 bytes (or samples) in length.
There are no hardware envelopes or LFO's, that's what the MSX has to do. Each int the MSX could adjust the volume of a channel to produce the effect of an envelope, and each int the MSX could alter the pitch a bit to produce the effect of vibrato or tremolo.

Why Konami games all sound the same? Ask them. They prolly liked the voices they've been using, or dunno, perhaps those voices were presets in their software to make SCC music, it's certainly not a limitation of the chip itself.

Wiki article

OK, now I get it. Very interesting to know that the SCC works basically as a (small) sample replayer. That means that the SCC can really produce different sounds. However, having to manage ADSR envelopes through interrupts must be time consuming.

Although I must add that my remark concerning the sounds being similar was not only for Konami games. For example, I was surprised to find that although the sound library of SCC Blaffer NT was big, the sounds were not very different from one another.

Regarding those envelopes, ADSR is not always flexible enough for a specific task. While it may sound complex to have to do your own envelope system, it also gives more freedom. As for time consuming: one register change in the SCC for each channel (see Wiki). Can't be that bad, no?

As for Blaffer NT: it's not a product I know personally, so I wouldn't know. It is however true that if you're creating waveforms by hand (e.g. drawing, like in SCC Musixx) that one typically ends up with the same kind of sounds, even tho they may look different when comparing them visually. It has to do with phase differences and such. E.g., "_\__" sounds the same as "___\".

envelope modulation and hw waveforms are in scc not so separate... it's possible to have a triangle output with descending tone simply putting the correct value in the scc (assuming you can do in only 32 bytes).

In the same way you can get a triangle wave out from psg simply setting the freq = 0 and the envelope to triangle wave form for a specific channel.

Quote:

Why Konami games all sound the same? Ask them. They prolly liked the voices they've been using, or dunno, perhaps those voices were presets in their software to make SCC music, it's certainly not a limitation of the chip itself

Which brings me to ask these questions :

1) What was the software Konami was using to write their SCC music ?
2) Did someone analyzed the replayer Konami used in their games ?

1) prolly nothing fancy.. here's a nice read about it.., tho for later stuff, I wouldn't know. Could as well have been something MML'ish
2) not sure, there have been BGM demos around, but perhaps those demos also had the original player ripped..