#85

Saw it get added to modulargrid the other day, looks like Klangbau Köln are planning something soon!

Out of interest, have any of you had a go of the desktop unit? I built one a year or two ago, and the sounds are great, but the user interface just wasn’t fun or satisfying for me to use. Curious about what CV control would actually add to the experience.

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#86

Never actually used one in person. I just love dx/FM sounds. :grinning:

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#88

I’ve been incorporating a PreenFM2 into my performance rig over the last few weeks. I’m liking almost everything about it.

The synthesis model includes 4 “performance parameters” which can be mapped via the modulation matrix to many things, and can be mapped to more than one at a time, with individual scale factors. This is the key to performability here: I’ve got the four for each instrument (so 16 total) mapped to physical knobs on my MIDI controller. With suitably construted voices, this becomes a very performable multi-timbral set up.

Now, patch editing on the unit is feasible - and doing things like adjusting the mod matrix is relatively easy with very shallow “diving”. Other things are admittedly hard, but the stand alone patch editor works solidly, and makes editing pretty easy. Editing is essential, as most of the example patches, and clearly none of the imported-from-DX7 patches, have any performance parameter mappings. But again, at least doing the mod matrix on the unit itself is fine.

Lastly, for a Eurorack version, I imagine that the 4 CV ins would map directly to these 4 performance parameters - which for FM would be far more useful than picking some subset of the patch parameters and bringing those on out CV - since you’d always be wishing for a different one. Here, the mod matrix lets you pick.

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#89

I have a question for you FM experts here :slight_smile:

I’m helping building a FPGA(ICE40) eurorack module dev kit (fpga+adc+dac+mcu) and as a first project I’m thinking of turning it into a multi op FM voice. Interface will be challenging and I started thinking of approaching the algorithm selection differently to keep the interface small.

I’ve never programmed an FM synth before. Do I understand it well that the operator algorithms are just a simple matrices of connections between ops and with the option to feedback an op itself? Since the operators themselves would be simple blocks on a matrix within an fpga, I think this would be easy to accomplish. What if we would treat these connections not as simple hard connections, but more like attenuators, like a matrix mixer? This would allow you to interpolate between algorithms and discover new sounds between existing algos? Would having audio rate cv control over a set of algorithms be interesting? Have there been experiments with this before? Am I asking too many questions, hahaha?

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#90

Many many many years ago I wrote a 6 operator FM synth in PD that did exactly this. The primary interface was exactly what you describe. pretty much an FM matrix mixer. I controlled the patch through a peavy 1600x faderbank and was able to do some pretty incredible stuff with it. The main issue was that there 36 possible faders so I had to switch between scenes on the peavey. I ended up creating “presets” and using the faders to lerp between them

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#91

Cool! Have you tried to interpolate between presets? I imagine one pot/cv input to morph over a sequence of presets :slight_smile:

#92

Yeah I remember it working pretty well. The thing I really wanted to do was control ADSR’s stages for each of the 36 input stages (was super into crazy Autechre FM shenanigans at the time) ‘morphing’ between presets was the best control over that beast I could get to.

I did end up doing another version that was a 4-op synth with an AR on each input, which I controlled with 2 Peavey scenes and that also yielded some nice stuff. Mostly for percussion. I ended up shelving most of that when I moved over to ableton live in the early 2000’s (its been a long while)

#93

I think there’s too many possibilities for one to get something useful along the whole range of the pot, simply because the fundamental frequency has the ability to change wildly as modulators become carriers. In principle, sure, although I suppose it would drastically alter the kinds of patch you’d want to set up.

I’d play around with programming FM, be that in PD or on something like a Volca FM, if you can, simply bc you’d want that experience in order to have a hope of making a good interface.

ETA: this is in response to something that would change the algorithm with a pot or CV control. morphing presets, on the other hand, would be a VERY nice thing to have.

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#94

I know that Elektron did a lot of work to tune their pots in the Digitone, to give them a range of all-sweet-spots. They weren’t even talking about modulating algorithms, but just the parameters of modulators and carriers.

I’ve never heard of FM algo lerping before, and I have to admit I’m super curious what it might be like, but I suspect it will need some tuning.

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#95

yeah, I think there’s a lot to be had in designing that kind of interface. The main thing that keeps one from doing something like this with the data slider on a DX7 or the Multiply or Wave knobs on an Akemie’s Castle is the clickiness inherent in those discrete transitions is miles away from the feel of “fiddling with the cutoff knob”. Be interested to fiddle with a Plaits in 2-op FM mode for this reason as well.

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#96

Yeah the thing to remember is not only do you want to control the amount of input from one oscillator to the next, but controlling modulator and carrier pitch (within a specified range) is very important. A lot of the work I was doing was around 2 modulators in a series, the middle one being low frequency that I would ramp from an audio range (like 120hz) down to LFO range (.25hz) with a quick attack and a variable release. this would give you a pretty good impact noise and then some cool wobble as the middle carrier acted like a pitch LFO. Add some enveloped feedback to the middle carrier and just with 3 oscillators and a bunch of control points you got a massive range of sounds.

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#97

I like some things that “DX-style” FM can do, but modular really opened my third eye to other kinds of FM. I’m not even in it for the noise that much, but there’s something gorgeous about linear TZFM on the Hertz Donut when the modulator is off-tuned a little, and in whatever the hell E370 is doing in its linear TZFM that makes it so angry, and in exponential FM on the Double Helix whether using a sine, saw or square as the modulator, and in getting FM to fight with oscillator sync or a PLL…

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#98

… I am ABSOLUTELY gonna see if the Pitch EG on my DX7 is capable of doing this tonight bc that seems like it would be amazing fun. If not I guess I finally have a great reason to build an FM Max patch.

ETA: it can’t. hello MSP!

Abstractly as I accidentally get sucked further and further into the intricacies of DSP for music, I’m beginning to really appreciate the usefulness of FM, especially when digital was more uncharted territory—the fact that if your operators are sines you get a finite spectra really improves the situation of aliasing, since there will only be a finite (and usually very small) number of aliased harmonics if there are any.

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#99

hey @zebra @cannc

is this possible to run on norns? what changes might be needed to use this as a synth engine?

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#100

yeah its possible, would need a fair amount of cleaning up but nothing too substantial

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#101

@Starthief Do you feel like accounting for your provocation that “2-op FM is better than 4-op or 6-op”? I’m intrigued.

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#102

It’s partially just personal preference. In a certain sense, I like working with simpler parts and assembling a whole from them.

I had a DX-100 back in the day, and then a DS-8. Later when plugins came around, I never really recaptured the love I had for those. FM was something I used occasionally for weird digital breakup noises, basses or glassy pads (usually with two operators, or an algorithm with a pair of detuned modulator-carrier pairs) but not a major part of my sound.

One of the first things I did when I got my first module (Tides) was to FM my Microbrute with it. And that was pretty glorious. I discovered there are all kinds of flavors of FM beyond Yamaha-style phase modulation. It was a bit like when I realized Chinese food goes way beyond the fried rice my parents had always ordered :laughing: And then I got deep into West Coast style complex oscillators, wavefolders and LPGs… 2-op FM at its best.

I tried a Volca FM and a Reface DX a few months ago and found I just didn’t like either all that much; I also haven’t been messing with FM8 or other “traditional” FM software at all in the last couple of years.

So now I have:

  • Hertz Donut, which is great for dynamic linear TZFM and those Yamaha-ish bell-like tones and has noisy digital shapes, but there is no restriction on frequency ratios so you can set up wildly inharmonic tones or some nice subtle beating, or you can sequence them separately, you can hardsync the VCOs to each other or something else, cross-modulate, and so on. Or FM eiither or both VCOs from another source, for linear or exponential FM. But most often I just use its internal FM bus for 2-Op FM.

  • E370, in which each of its four VCOs has a sort of tame and gentle 2-Op FM mode but you can apply them to any wavetable, not just sines. It also has a phase mode where you can use audio rate phase modulation for a similar, but subtly different effect. And on top of that, it’s got FM inputs, which can be assigned to exponential or linear TZFM modes at three different strengths, and the linear comes out really dirty and weird compared to everything else even if you filter the modulator signal. And since it’s a wavetable synth, you can give it banks that were created through FM synthesis and stack it even further. But honestly: with all those possibilities I tend to use it mostly for 2-op, exponential FM.

  • Double Helix, which is an analog saw-core complex oscillator that does exponential FM only, but is full of character. Using saw instead of sine for the carrier sounds pretty nice.

  • Rings, which has a poorly hidden 2-op FM mode, and an exponential FM input

  • Plaits, which has a similar 2-op FM mode.

Also there’s both Aalto and Arturia Buchla Easel V repping the West Coast in software, and now PortaFM for the old Yamaha sound. And I find I still like it, but mostly when I do crazy things with it instead of electric pianos and bass and brass :slight_smile:

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#103

Yamaha phase modulated electric piano and brass sounds, while classic, are what I blame for a host of aspersions cast on 80s synth-centric music. Our ears got tired of those sounds long before they stopped getting overused.

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#104

just curious what was it called? the pd patch i mean

#105

wow, I’m very glad I asked, thanks for the in-depth response!

It’s interesting, I’m finding that since the DX7 does its little 80s best to appeal to the pianists of the world, I find myself programming sounds that respond well to pianistic expressions. Mental note… see if I can get it to growl…

The various kinds of FM you describe do sound really exciting, and I think the modular ones really well suited for a modular approach.

@jasonw22 I definitely have my own e-piano rendition (really buzzy and dark, since I was trying to mimic the sound in a Cure song) and… I’m not sorry :joy:

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