SWAY - a synth modeled after the Yamaha SY77

[EvilDragon]

However Yamaha giveth and Yamaha Taketh Away and we also lost algorithms 19 and 20 where each of those have three modulators and two carriers both modulated by one modulator and there is no direct equivalent in SY77. One could argue that doesn't matter as you can add feedback loops going from a modulator to a carrier which can accomplish the same thing which is true, but it's also not the same workflow wise which means the DX7 is able to do things the SY77 can't namely have Algorithms 19&20

Not correct. Algos 19-20 are algos 40-41 on SY.

[IvyBirds]

However Yamaha giveth and Yamaha Taketh Away and we also lost algorithms 19 and 20 where each of those have three modulators and two carriers both modulated by one modulator and there is no direct equivalent in SY77. One could argue that doesn't matter as you can add feedback loops going from a modulator to a carrier which can accomplish the same thing which is true, but it's also not the same workflow wise which means the DX7 is able to do things the SY77 can't namely have Algorithms 19&20

Not correct. Algos 19-20 are algos 40-41 on SY.

Algos 19 & 20 on the DX7

Screenshot_20250919-072103.jpg

In 19, operator 6 is modulating 4&5 with a feedback loop going to itself and in 20, operator 3 is modulating 1&2 with a feedback loop going to itself

Algos 40-41 on the SY77

Screenshot_20250919-071748.jpg

In Algo 40 on the SY77 operator 3 is only modulating #2 and doesn't have a feedback loop going into itself, instead it has feedback loop is being sent into 1

So no it's not the same and in fact is nowhere close

And in Algo 41 on the SY77 Operator 6 is only modulating #5 it's not modulating 5&3 which it would need to do to be the equivalent of Algo #20 on the DX7. You will also notice that there are two Modulators modulating a single carrier in the other group of three in the DX7 while in the SY Algo 41 that is not the case as we have three stacks of two

You could have a feedback loop from #6 go into #3 but then it's not going back into itself as in the DX7

So like I said in SY there is no equivalent to Algo 19&20 on the DX7

I use 19&20 quite a bit on the DX7 because using different envelopes for the two carriers that have the same modulator you get morphing timbres

I realize we are getting deep into the weeds here with FM Synth Nerdery, (which is fine as I am an FM Nerd) and like I said before you felt the need to try to correct me that there is an argument to be made that you don't need those algos on the SY because you can cheat and use the Feedback Loop to accomplish a similar task which in this case rather than a direct connection between a Modulator and two carriers, you are stealing a feedback loop, not to actually loop or even feedback anywhere but simply as an extra output to send to an input and that is absolutely true, but the fact remains those Algos don't exist in the SY.

[EvilDragon]

This document seems to corroborate my claim, though:

https://www.xfactory-librarians.co.uk/D ... ersion.pdf

Turns out there's a bit more work needed to be done on SY77/99 to get the same thing, but you can get the same thing as on DX7.

And even if we take all of that away, you can still program your own algo via sysex, which then definitely allows you to completely duplicate algos 19/20 from DX7...

So, you cannot really say those algos "don't exist" in SY. They do/are attainable.

[IvyBirds]

This document seems to corroborate my claim, though:

https://www.xfactory-librarians.co.uk/D ... ersion.pdf

Turns out there's a bit more work needed to be done on SY77/99 to get the same thing, but you can get the same thing as on DX7.

And even if we take all of that away, you can still program your own algo via sysex, which then definitely allows you to completely duplicate algos 19/20 from DX7...

So, you cannot really say those algos "don't exist" in SY. They do/are attainable.

Sure you can because they don't exist which is exactly what I said

And they most certainly are not Algos 40-41 as you claimed

are there work arounds? Sure I have always said there were

But the issue remains. If I launch a TG77 how do I recreate the functionality of using Algo 20 from the DX7? You can't even using feedback loops, at least from the hardware. If you have a Sysex Editor you could build it, but out of the box from the factory you can't as that algorithm doesn't exist

Which has always been my point. The SY series had a different workflow and user experience than using a DX7, and FM-X has a different user experience and workflow than using an SY77 even if you are able to build your own algorithms on both to accomplish the same use case

One of the biggest head scratchers from Yamaha for me is when they built the SY series why didn't they just duplicate all of the 32 algorithms from the DX7 as algorithms 1-32 exactly the same way, and then have extra algos that used SY77 capabilities from 33 onwards. Most of them already have direct equivalents so why not just reproduce all of them exactly the same way and number them the exact same way? All of them can be very useful with the expanded waveforms and even more so with two more feedback loops

[sheaf]

Maybe I'm missing something, but it does look like DX7 algo 19 is the same as TG77 algo 40. The only difference is that the roles of 6-5-4 are swapped with 3-2-1 and vice versa, but they seem to be functionally equivalent? Without the need to change any feedback setting or go into the custom mode through SysEx.

Similarly, DX7 algo 20 seems exactly the same as TG77 algo 41, with a single feedback loop in operator 3.

Is this a difference between the SY77 and the TG77? Your screenshot of the manual only shows SY77 algo 41 & 42, not 40 & 41. My TG77 display shows the same algorithms for 40 & 41 as your DX7 screenshot is showing for 19 & 20.

tg77_algos.jpg

[EvilDragon]

I sincerely doubt there'd be such a major difference between SY and TG. But yes the only actual difference seems to be in how operators are numbered.

I can get OPS7 alg 19 sounds in Sway alg 40 and the same for DX alg 20 in Sway alg 41... No custom fb routing either. It's just there, readily available.

[sheaf]

I doubt it too because then the patches wouldn't even be compatible between them, but in that case there is an error in the SY77 manual. For algo 40 it shows feedback from 1 to 3, while it's really 3 going to itself, and it also doesn't show 3 modulating 1.

[EvilDragon]

That's actually properly Occam's razor - the manual is wrong

[IvyBirds]

Maybe I'm missing something, but it does look like DX7 algo 19 is the same as TG77 algo 40. The only difference is that the roles of 6-5-4 are swapped with 3-2-1 and vice versa, but they seem to be functionally equivalent? Without the need to change any feedback setting or go into the custom mode through SysEx.

Similarly, DX7 algo 20 seems exactly the same as TG77 algo 41, with a single feedback loop in operator 3.

Is this a difference between the SY77 and the TG77? Your screenshot of the manual only shows SY77 algo 41 & 42, not 40 & 41. My TG77 display shows the same algorithms for 40 & 41 as your DX7 screenshot is showing for 19 & 20.

tg77_algos.jpg

You are right sheaf I cropped the wrong image. My mistake, that's what happens on two hours sleep

Anyway I'll use yours as they are significantly cleaner rather than from the manual

Here are the DX7 Algos in question

Screenshot_20250919-072103.jpg

Here is your picture of the screen

tg77_algos.jpg

Let's look at the DX7, it's in no way the same as the SY. On the DX7 operator 6 is in the same position as operator 3 on the SY. In the DX7 that operator has a fixed feedback loop and that fixed feedback loop is attached to itself

In the SY it's not attached to itself, instead it's attached to operator 1. There is no predefined Feedback Loop attached to itself.

Beyond that on the DX7 Operator 6 is directly connected to 4&5 without any kind of feedback loop. That is the way that Yamaha predefined the Algorithm(s). You have a single modulator directly connected to two different carriers.

On the SY this is not the case, take a look operator 3 is only directly connected to operator 2. It has no direct connection predefined in the algorithm connected between operator 3&1. It is using a feedback loop to accomplish that

The issue with using the predefined feedback loop to not be a feedback loop but rather a simple connection between two operators with no feedback occuring is that the modulator as predefined by the algorithm itself is not feeding back and modulating itself like is occuring in the DX7

To put it another way on the DX7 if I want to have a modulator modulate itself and two additional carriers, there is a predefined algorithm for that exact scenario. I can simply select Algo 19 or 20 and away I go. I don't have to change anything. If you want to do that on the SY I have to use feedback loops and it's not predefined

Can you use feedback loops in the SY to recreate the functionality of fixed connections predefined in the algorithms between operators? Sure I never said you couldn't but it's not the same and there is a difference

One thing I really hope your plugin will allow for is the ability to easily create as many Algos as we want, name them whatever we want, and put the operators in whatever order we want

The first thing I will do is recreate exactly all of the DX7 Algos exactly as they are in the DX7 and call them DX7-1, DX7-2, Etc. With the numbers of the operators all exactly the same, then so the same with the TX81Z Algos

[EvilDragon]

On the SY this is not the case, take a look operator 3 is only directly connected to operator 2. It has no direct connection predefined in the algorithm connected between operator 3&1. It is using a feedback loop to accomplish that

This is again incorrect. There is BOTH a self-feedback on op 3 AND it modulates ops 1 and 2 in SY/TG/Sway.

I've had gentleclockdivider fire up his TG77 to check this. You are wrong. Those algos DO have pre-wired feedback on op 3, even if it's not in the alg schematics - so they ARE identical to the DX7 algos in practice. Sway emulates this perfectly - op 3 has pre-wired feedback just as it is on SY/TG.

[IvyBirds]

I've had gentleclockdivider fire up his TG77 to check this. You are wrong. Those algos DO have pre-wired feedback on op 3, even if it's not in the alg schematics - so they ARE identical to the DX7 algos in practice. Sway emulates this perfectly - op 3 has pre-wired feedback just as it is on SY/TG.

Interesting about this predefined feedback loop you say is in sway. Tell me is it loop 1,2 or 3? I would assume there is some kind of control in sway that would adjust that level so which number is it? And since Operator 3 is also modulating Operator 1 using a feedback loop what number is that one?

I don't have the Beta so I can't check myself

Oh and for the record check out this quote from February 1990 SOS Magazine

"Two DX7 algorithms have no obvious direct equivalent on the SY77, algorithms 19 and 20: each of these have three modulators and two carriers both modulated by one modulator. None of the AFM three carrier algorithms has a modulator which modulates two carriers."

https://www.muzines.co.uk/articles/sy77 ... ttons/5757

Again there is a work around using feedback loops and it explains that later in the article

[EvilDragon]

Same is on TG/SY by default as confirmed by gentleclockdivider.

This may have been added in a firmware update, so I wouldn't necessarily fully believe articles online which might have deprecated info. Do you have an actual TG/SY unit? That would be the easiest way to check.

Also, do you really think sheaf would do this incorrectly after spending years working on Sway? I don't think so.

[sheaf]

Yes, the feedback loop in 3 is attached to itself, and I believe the diagram shows that too. If it were attached to 1 you would see a wire going all the way from the bottom output of 1 back to 3. You can see the output of 1 is not connected to the input of 3. But the output of 3 is both connected to the input of 3 and the input of 1 and 2. So 3 modulates 1 and 2 (and itself through feedback).

Internally the way 3 can modulate both 1 and 2 is indeed through the feedback bus, but that's equivalent to direct modulation or modulation through the accumulator because it's not actual feedback yet. The 3 feedback busses act as 3 additional storage units that you can use to modulate lower level operators (they are named FF1/FF2/FF3 in Sway). Only in the next sample frame do they get filtered and are used for actual feedback. It doesn't matter if you modulate a carrier by OP, ACC, or FF1/FF2/FF3, as long as they contain the same value then the modulation will be the same.

I guess they had to connect it this way for algo 40 because the accumulator could not be used, as it needs to preserve the output of the 6-5-4 stack. In the DX7 that's not the case because the 3-2-1 stack there is calculated last so they can use the direct operator input instead. Not sure why they reversed the role of 6-5-4 and 3-2-1 between the DX7 and the SY77, but the output is mathematically equivalent if you swap the settings for 6-5-4 and 3-2-1. And the algorithm is configured this way out of the box, so I think the writer of the SOS article is simply mistaken.

Currently there is no way to save custom algorithm presets, but that's an interesting idea! I'll add it to the list of possible future features.

[oneOeight]

Here's one vote for skipping the factory presets.

Yes, maybe an early adopter version without presets would be an idea.
Most people would want to get their own old presets going if they owned one before.
Getting the ROMs is not difficult.

[phreaque]

One major aspect of making presets during a beta testing phase, is to find bugs.
Nobody will like a partially broken plugin.