Modular (mono) FM synth build

JamesM · 2022-06-23T03:33:56.586Z

your_lamp:

What size is the rack you’ll be using?

168HP

Thanks for the suggestion s there.

estragon · 2022-06-23T03:42:09.784Z

So you’re not trying hard to replicate a DX7, but you’re intent on 6-op to approximate it, am I understanding correctly? As much as I’d love to see someone who isn’t me throw money at this, please try more of the more practical solutions offered in this thread and get a feel for analog FM before you start attempting to put something together on this scale. I can guarantee that planning a setup well around a DPO will get you a lot further than just winging it and cramming a rack full of oscillators.

JamesM · 2022-06-23T04:24:59.106Z

estragon:

So you’re not trying hard to replicate a DX7, but you’re intent on 6-op to approximate it, am I understanding correctly?

Yes, but not necessarily six op. Four (or three) ops would be a good start, based on my experience with digital FM synths.
And yes, I’m totally open to the other suggestions above. But, I’m too fatigued trying every digital FM I can get hold of.

m13wo · 2022-06-23T04:32:13.701Z

6 OP analog FM in eurorack form. No, man, this is stupid.

Analog FM ≠ Digital FM.

Don’t even waste your money, it will suck.

Get an Opsix. It has plenty of hands on controls. More than anything really.

your_lamp · 2022-06-23T04:57:38.428Z

JamesM:

168HP

Honestly you probably have more rack space to fill then your budget will support — which is fine, you don’t need to fill the whole thing right away, grab some cool looking blank panels to cover the gaps and enjoy the fact that you’ve left yourself room to grow (because you will want more modules as you get into it).

A lot of people are reading into your “6-op FM” concept as a sticking point against going modular. They’re probably right, but if you’re more interested in the “modular” aspect of this idea than “6-op” part of it, you can certainly make an awesome FM-focused modular mono synth for $1500 in 168hp.

Microtribe · 2022-06-23T05:39:19.393Z

JamesM:

I love it. I’m gonna give it a go.

I did end up patching…
Its a monster alright!

pdp · 2022-06-23T06:40:27.435Z

I read that modules from acl are good higher end vco‘s well suited for nice sounding simpler analogue fm.
When i try to do simple fm on dominion it mostly sounds not good for me, but thats because of me probably a big part.

Octagonist · 2022-06-23T07:25:57.212Z

A leftfield idea: would a Matriarch be enough FM for you? It’s a fabulous semi-modular; the LFOs reach audio rate and can key track; each oscillator has linear FM CV in; the attenuators have some funky mixing and ring-mod routings; etc. Plus two filters, two envelopes, the delay is gorgeous. I can imagine it’s not flexible enough for many FM sounds, but could it be enough for you, Op?

Slim · 2022-06-23T08:19:33.281Z

Did you consider building a modular rack around a preenfm ?

Nils · 2022-06-23T08:30:57.993Z

What about Akemie’s Taiko? It’s a self-contained 4-operator through-zero FM module.
Admittedly, it’s geared for percussion duties (no attack portion on the envelopes), but it has a 1V/oct input and apparently works well for melodic sounds too.

image497×700 94.3 KB

JamesM · 2022-06-23T08:40:28.797Z

I tried it out on my Subsequent 37, two audio rate LFO’s and decent routing options. Got some good and interesting results too.

jamesstiff · 2022-06-23T10:05:20.334Z

LaughingAnimal:

Akemie’s Castle might be worth checking out

+1 for this suggestion. I’d don’t have Akemie’s Castle but it’s on my wish list.

Nils:

What about Akemie’s Taiko?

Akemie’s Taiko is great but as stated, it’s optimised for percussion. It can do melodic stuff but needs to be triggered.

Monobear · 2022-06-23T11:04:19.824Z

Just to second don‘t go analog 6 op fm. I have a Verbos CO and its hard enough to handle. Consider a Complex Oscillator and a Matriarch if you want to go crazy and mix it with a Digitone

Nils · 2022-06-23T11:35:33.872Z

What you are talking about here is “regular” audio-rate FM though (no phase modulation), and while it’s interesting on its own you won’t be able to achieve the glassy tones that you can get with proper through zero frequency modulation.

The DX family, Digitone, Preen, Opsix, VolcaFM, Akemie modules etc do TZFM. Most analog synths (apart from certain eurorack modules) only do regular exponential or linear FM. There is a big difference in the kind of tones you get from the two.

Sorry but I suck at describing the difference. Hopefully some of the smarter geezers on here will be able to explain it better. This is the best description I could find right now:

Richard Brewster's Electronic Sounds – 3 Jul 09

Teezer Through Zero VCO - Richard Brewster's Electronic Sounds

Ian Fritz, January 2009 This module is a sawtooth-based VCO capable of frequency modulation (FM) extending past zero frequency into the negative-frequency regime. Thru-zero FM provides a much wider and ... Read More

Est. reading time: 4 minutes

geecen · 2022-06-23T12:04:49.579Z

Read what others have said about trying to do it in analogue modular Vs digital when you’re aiming to emulate a digital synth.

But anyway, if you’re up for multi operator analogue modular FM (which I am and is cool ) you should check out the nonlinear circuits FM op and valmorification modules for osc and envelope as this is what they were designed for. Tricky DIY build if you’re up for it, of you can buy built.

MichaalHell · 2022-06-23T12:24:40.431Z

As for oscillators you could get away with 6x 2hp sine. Get something like a Bastl waver (2x?) and a stereo filter (ikarie?)

As for envelopes and VCA’s you can’t go wrong with MI Stages and Veils

plragde · 2022-06-23T12:57:24.849Z

geecen:

you should check out the nonlinear circuits FM op

Unfortunately the built price of this is $250.

Here’s a decent explanation with accompanying video of the different kinds of FM. Understanding the Differences Between Exponential, Linear, and Through Zero FM - Learning Modular

LaughingAnimal · 2022-06-23T13:06:22.344Z

jamesstiff:

+1 for this suggestion. I’d don’t have Akemie’s Castle but it’s on my wish list.

Same here, though the number of modulators and vcas I feel I’d need to properly control it feels a bit overwhelming. Kind of considering selling off some of the analog focused stuff for it though.

I got excited about the FM capabilities Generate 3 + other modules brought, but I actually think I got better overall results from using Plaits, Tides, and Warps together. Cross modulating a bunch of analog vcos, filters and function generators is good fun, but digital FM in modular can be cool too

morecchia808 · 2022-06-23T14:21:14.241Z

I said it once, I’ll say it again: Humble Audio Quad Operator. It’s as knobby as you can get.

ModularGrid

Humble Audio Quad Operator

Humble Audio Quad Operator - Eurorack Module - 4 Variable Waveshape Operators for Linear FM Synthesis

And the Andrew Huang vid for all the haters:

trackerjack · 2022-06-23T16:20:16.311Z

3 x Frap Tools Brenso and perhaps a Fallistri or two.