FM Lab import weirdness with 4-OP FM patches

I’ve been having a blast importing my old 4-operator FM synths’ patches (YS200/B200, TX81Z) and they really convert very well, some differences but close enough for comfort.

However, there seems to be an issue with white-noisey types of patches. They sound great on the hardware, but become some weird warble in FM Lab. I can’t figure out what parameters are going wrong here, has anyone experienced the same? Here is an audio recording of the YS200 preset “Ice Age”:

Hardware (Yamaha YS200), as it should be:

FM Lab, warbly-weird:

Edit: I have the feeling the “Matrix” page is not always updated correctly. Some settings are left over from previous patches (esp. when loading the FM Lab presets). But that’s probably not the cause, just causing some patches to sound off.

Sounds like the type of Noise Sounds I did in the 80s on my TX81z, using S&H LFO on pitch and carrier level. I had similar problems when trying to recreate that technique on the FS1R or (later when I catched an affordable one in the 00er) on the TX802 or imported my old 4Op sounds on FM7.
I first thought it’s the speed only, but that it’s probably the poor resolution of the old 4Op LFOs as well, that are responsible for the noise.
On the Montage - after an update - their is a high speed mode for the LFO that works fine (but not identical to the TX81z) for noise in case FB Lab/Halion 7 I found out that the Noise waveform surprisingly effective for coloured Noise. Other than that I think to remember that the rate reduction filter types are useful for coloured Noise as well.

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Thanks a lot, that sounds like a very likely explanation! Then I’ll have a look how to fix/recreate those patches using Halion’s onboard tools.

FWIW, it may be to do with the hardware limitations of old modules such as the TX81z … I’ve seen patches where the “noise” seems to be the result of the D/A converters not being able to cope. The designers of the original sounds seem to have encountered these limitations, and yet were able to “misuse” them to produce great sounds, but of course, that’s pure speculation on my part.

It may be impossible to reproduce some of these sounds using an accurate software rendering of the FM algorithm, even if all the parameters are the same,

Seem like that’s the case indeed. So actually a full emulation with FM Lab is not possible. I guess I’ll keep my TX81z for a while then. :slight_smile:

Me too!

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I know this info is wide spread, but according to the service manuals the DACs were pretty sufficient with 16Bit and 48khz, at least on the later 4Op and newer DX7 Models.
It’s rather the internal resolution of the synth: To make the synth affordable and polyphonic Yamaha had to use some tricks, like rolling out the calculation by using lookup tables and working with the similar Phase Modulation instead.

Now that’s what I call dedication … great article!

I’m a rather a fan of dirty FM Sounds than oldshool DX Preset emulations, so I know that their are multiple ways to get the Dirt back into the FM - in case that’s what you’re looking for, due to the additional H7 Operator Waveforms with scalable overtone amount, fixed Frequency carriers down to 0Hz (that can be used as waveshapers and therefore additional hiss and distortion), as well as positive and negative Feedback for all operators.
So at least sound/character wise I wouldn’t give up on this, in case you’re willing to get into FM.


Yep, I’ll investigate a bit, getting into the ballpark is probably feasible. Just a pity there’s no 1:1 full emulation that would have allowed my TX81z to retire.

Limitations (and minimal approaches) can sometimes inspire creativity.
Also, if you haven’t already tried it, edisyn is very useful for these old modules.

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Great tip, thank you!

I’m no minimalist when it comes to synthesis, would even welcome additional functions like per Operator pseudosync or additive waveforms (with Kawai K5000 type formant or morphing filters) on FM-Synths.
Even so I still own a TX81z and used it regularly for more than 10 years, I would miss some of the added functionality of newer FM-Synths. I tend to use the additional Operators for Soundchanges/Parameter Morphing and rather regular using the pitch EG per Operator to add punch or additional movement.

@Alessio Some ppl. like to use the stereoping HW Programmer.