The yamaha FM synth chip that was used in alot of their keyboards as well as some of the best-sounding arcade games... Does anyone know of a patch that emulates all of its features? Or can anyone even tell me where to find all of its features & settings? I know it has 8 voices, with 4 operators to choose from for each (saw, sin, tri, noise(?)). But can anyone tell me what else it has in terms of digital or analog envelopes, filters, effects and all? If there's no patch for it I plan to try and make one, but I'm not finding much information.

I did find the datasheet, which doesn't help a whole lot. Here's what it says:

_"Generate up to 8 notes"

"Generate noise"

"Timbre can be altered temporally"_
How? I think that can be done by sweeping the modulator frequency or level controls - but are there auto-sweepers or hard presets?_

"High harmonic can be de-harmonized from the base freuency"_
What does that mean - that I can control the pitch of the highest partial independently from the pitch of the lower ones? Is this easy to do in pd? I imagine it will require FFT, or maybe I could erxperiement with networks of key-following filters?_

"De-harmonize between octaves"_
Anyone know what this means?

_"Interval setting of 1.6 cents."

"Add vibrato and AM"_
AM is just the volume envelopes, right? Or am I missing something completely?

If anyone wants to answer these questions, fire away, heh. I certainly appreciate it!

It's the same architecture used in all Yamahas 4 op FM synths like DX21, 27, FB01. IIRC it has 16 algorithms (wrongly called) which are fixed configurations of 4 operators - such as 2 parallel oscillators modulating 2 in cascade. Some of these include feedback paths and self feedback for generating noisy sounds.

Check out the detailed specs on any 4 operator Yamaha synth chip and you will dealing with roughly the same thing.

The above statements sound a lot like marketing talk, some of them don't even mean that much technically. They are saying the oscillators are all independent, that's all.

The DX7 structure has been implemented by Frank Barknecht in Pd , look at the PDX7 to see how.

AM is rapid modulation of volume that causes audiable sidebands. When the sidebands are inaudiable for low modulation frequencies we usually call the effect "Tremelo" not AM. Vibrato is slow frequency modulation, usually less than 10Hz

I think I have the manual for the TX81z if that would be helpful.

thanks guys, I'll poke around and see if I can find some manuals. nestor if you have one that's ready to upload that's cool, but don't go outta your way, I'm trying to be more resourceful, heh.

AM is rapid modulation of volume that causes audiable sidebands. When the sidebands are inaudiable for low modulation frequencies we usually call the effect "Tremelo" not AM. Vibrato is slow frequency modulation, usually less than 10Hz

Man that's a great analogy! I had figured out the relationship between FM and vibrato, but I didn't realize the one about AM and tremolo. Thanks!