PreenFM3

[Boonie]

Oh that sounds cool actually

[Lizard-of-Oz]

Spent some more time with Chimera yesterday night, I’ll just share my thoughts, do whatever feels right with them.

First of all, I did not experience any obvious bugs, and the sound is great, I’m very happy with the quality and parameters of engines, filters and effects. So far I did not test projects, loading and saving, or the mod matrix.

Am I right to assume Chimera took some inspiration from Polyend Synth? It has some ideas that I liked about the Synth, but it seems to skip the things I did not like. I was especially fond of the physical modeling in the synth,

Synth Engines

• haven’t played with the original firmware much (just 1-2hrs), but I think that it is doing a better job making the complexities of FM synthesis accessible to the user. One page with 18 (?) subpages for the oscillator is challenging. Navigation back and forth is better than just one direction, but still. Probably the hardest problem to solve in Chimera UX. Original firmware made Operators first-class citizens of the while experience. This was simple, because it was designed as FM synth. And it had other drawbacks. I’m thinking maybe a special FM edit mode might be one way.

Filters

• the basic idea of selecting model, and then the filter type works great
• I would expect envelope modulation on each filter, but that would mean you have a dedicated filter enveloper, or a setting which envelope to use
• I found I reliably change the filter model when I reach for cutoff. IMHO the most intuitive placement might be cutoff be top left, resonance top center, envelope amount (if you have it) top right. Model and type in the lower row, or on the second page even.
• the filter visualization is odd, I think the resonance part starts too high vertically
• it’s also odd, but probably correct that FM amounts shift the cutoff frequency. I did not expect this, and I think it can be visualized without changing the range of the display value of another parameter.

Modulations

• will need to dive deeper into this section for a more informed opinion, just random thoughts here
• somehow I had a hard time discovering envelopes and LFOs, but I did find them eventually, in the (retrospectively) obvious place. when the sub pages are all visible (see below) that would be easier to discover
• what I like about the Synth is the separation of mod matrix and macros. But there are good arguments for keeping them together, too
• most versatile mod matrix is on Waldorf synthesizers, because they have functions, too. I like the mod matrix of the Pulse 2, because it shows more than one destination, so you see what’s going on. )

Mixer:

• there’s one place where I thought the levels of chorus, delay and reverb might go to the bottom row, instead of the top row (the other row is empty)
• having two illustrations of the effect chains at the same time is off

Usability

• it occurred to me the lowest line where you show the pages is empty everywhere but below the active pill. If you lay out the sub pages horizontally, with “<” and “>” at the end to indicate there’s more, “SEQ” and “EDIT” keys are more intuitive to use.
• maybe it makes sense to separate configuration and parameters, like in the Tonverk, or at least in two different sub pages (filter model and type, envelope to use, effect algorithm etc.)

[nilsec]

@Lizard-of-Oz Thanks again, this is exactly the kind of feedback I need. I’ve added everything to the list for 0.2.0.

• Page indicator: Really good idea. Showing the sub-pages side by side along the bottom should make navigating EDIT and SEQ much more intuitive. Instead of the confusing up/down vs. left/right navigation, you’ll be able to see the pages and move through them horizontally. It also means no more hidden pages. I’m implementing this right away.

• FM editing: Could you elaborate on what you have in mind for an FM edit mode? The OSC pages are currently organised by parameter intentionally. For example, you can see the attack values for all six operators at once. My usual workflow is to choose an algorithm, set the waveforms, and then work through the envelope stages, comparing operators side by side. Per-operator pages would make that harder, at least for me. But I’m curious what’s getting in your way with the current approach.

• MOD matrix vs. macros: What would you change about how these are separated? If you have an example of something you tried to accomplish but couldn’t, that would help me understand the problem.

• Filter page: I’m reorganising this. Filter kinds and types will move to the front alongside cutoff and resonance, while envelope amount will be one press away with the other modulation routes. Good catch on the resonance value displaying too high at its default setting, too. That’s a bug.

• FM amounts and cutoff: I’ll separate the base cutoff value from its modulation, so it no longer looks like the cutoff is changing by itself.

• Envelopes and LFOs: The new page indicator will make every sub-page visible.

• Mixer: I’m moving it down one row and displaying one effect chain at a time.

• Configuration vs. sound: These parameters will be separated.

As for the Polyend comparison, I’ve actually never played the Polyend Synth! Some of the physical modelling in Chimera goes back quite a bit further.

I originally wrote alternative firmware for the Ambika, including a few physical-modelling algorithms of my own that I’ve since ported to Chimera. In fact, the Ambika’s limited processing power was one of the reasons I started Chimera in the first place. I had far more ideas than those little processors could handle, and the PreenFM3 finally gave me enough headroom to explore them.

The MODAL engine’s mode bank and exciter-into-resonator architecture were heavily inspired by Émilie Gillet’s Rings and Elements. Her implementations are in C++, so I spent time studying the maths behind them and writing my own implementations in Rust.

Another big influence is the Korg Volca Drum. I love its approach to building percussion sounds through digital physical modelling, and it’s been a major inspiration for the drum engine I’m working on.

A couple of other things coming later: I’m combining drive and wavefolding into a single FX slot available on every filter, with SOFT, FUZZ, and FOLD modes that can run before or after the filter. I’m also planning a Buchla-style low-pass gate.

Finally, projects, save/load, and the modulation matrix are probably the least-tested parts of Chimera right now. If you get a chance to spend some time with those, I’d really appreciate hearing how they behave.

Thanks again for taking the time to write all this up. It’s genuinely useful to hear how someone else approaches the instrument, especially when their workflow differs from mine.