Reply 320 of 321, by yawetaG
mattw wrote on 2020-12-29, 20:33:yawetaG wrote on 2020-12-26, 18:33:mattw wrote on 2020-12-21, 09:36:
...i kind of demystified "fmAyA" - it's actually "fm4y4". so, 94B instrument definition could be either PCM(Wavetable) or FM. that means "fm4y4" whatever it exactly means, is the only "loop mode" available with FM instrument.
Google "Roland FxM". Some Roland synths (JV-80 and descendants) have a limited FM modulation option. As an aside, JV-80 uses the same GP4 chip as the SC55, so FxM might be part of the GP4 chip's abilities and just inaccessible in SC55...
I believe you're right, in 94B that "fm4y4" thing is dual 2-operators FM (that's why it's designated as "4", i.e. "2x2") and that Roland FxM is also 2 operators FM (1 carrier and 1 modulator). I think 94B has Dual such FM synth, because 94B can do 2 samples defined for one instrument, i.e. I guess it is connected to what you outlined here:
Yes. You can find a simple example of FxM on this page: https://www.polynominal.com/roland-jv80/index.html (under TECH, last bullet point). It's kinda crappy.
BTW, upping the modulation sensitivity on a SC-55 results in modulation effects similar to that example on some patches at high modulation values (using the modulation wheel, CC1), so it might be that the parameter is not editable on the SC-55, but still present nonetheless in the synthesis engine and ROM presets.
So, once again, I am not expert on those topics, but similarities between 94B and Roland are staggering in my opinion. […]yawetaG wrote on 2020-12-26, 17:59:
The usual way Roland implements detuned patches on their other TVA/TVF synths is having two samples played at once, one of which is detuned.
So, once again, I am not expert on those topics, but similarities between 94B and Roland are staggering in my opinion.
[EDIT] correct me, if I am wrong, but:
TVF is essentially the same as what 94B has: VCF, which is Voltage Controlled Filter
and I presume Roland TVA is essentially the same as what 94B calls VCA (Voltage Controlled Amplifier). I am very close to think direct conversion between SC and 94B is possible. There are too many identical structures/parameters, at least from my point of view.
VCF and VCA are part of the basic designs for the components of a synthesizer, dating back to the time that analog synthesizers were initially developed*. In a digital synthesizer they do not need to exist as distinct electronic circuits or components.
If 94B is actually a (not so legal) copy of the SC-55 these generic terms might have been used to avoid scrutiny into the format...
* There's a nice book by Peter Manning, "Electronic and computer music", that recounts the history of synthesizers in quite a bit of detail. Recommended.
For the MIDI implementation and relationship between parameters in MIDI and ROM, I came across this older page that basically provides an annotated shortened version of the controllable parameters:
Some comments on that page make me believe that the ROMs might have been cracked before, but it's likely the information will be hard to find because it was likely published on mailing lists or maybe usenet. Guess I'll have to trawl through Google Groups' archived posts (DejaNews archive) and hope to find something between the retroactively posted spam... 😐