Yamaha DX-7 Algorithm 16 patch

#1

So, I received my Axolotii (I ordered two) a few days ago, and started patching and trying out some example patches I downloaded from this community (thanks everyone!).
It's still quite a search to find the objects in all the different directories.
As a first try, I decided to try and patch a DX-7 FM/PM algorithm. Arbitrarily I chose algorithm 16, no idea what typical sounds using this structure sound like (or whether they are any good! smile ). I had a DX-100 a long time ago, but really didn't get around to programming new sounds myself (do not like menu structures).
The idea is to build the two Axolotii into a Eurorack module, possibly with some CV inputs / potmeters.

The patch is still pretty limited right now, just a single envelope generator, and two LFO's. No velocity yet, no attenators between oscs (were there any in the original DX-7?).

Let me know what you think.

Ps. Right, I cannot upload any patches right now, I'll post a link to my public dropbox in a minute.

#2

Yamaha DX-7 Algorithm 16 patch v1

By the way, I used Wout Blommers' work, to be found at:
Nord Modular Book FM Algorithms

#3

Heh, FM was the first thing I did too -- and Axoloti does it extremely well!

I made a small subpatch for a single operator with oscillator and envelopes together, that way it's easy to wire up any algorithm.

#4

JV_DX7_Algorithm16_mod.axp (11.0 KB)

I modded your patch a bit smile

2 envelopes and a feedback path

#5

FS1R algos anyone? smirk

#6

Thanks all!

I'll have a look at your suggestion later Martijn! Modlab tonight?

rvense, can you share that sub patch?

#7

I did patch a formant filter a few days ago.
I patched also a 16 step sequencer you could use to do some kind of formant sequencing.

If you're interested you can find them on this forum

However i don't know if the yamaha fs1r did its magic with filters or with actual fm synthesis

#8

Not rocket surgery:

op.png726x523 29.6 KB

I used AD envelopes since it's mostly for percussion to begin with.

Will look at a mixing/routing module tonight, probably.

#9

Hello guys, for your information one can't do fm synthesis with feedback proper on an audio engine with block-based (vs individual) sample processing, because of the inevitable delay in the feedback path this will introduce (16 samples in the case of the Axoloti). One needs feedback in fm for example for synthesizing noise and more metallic or harsh or analog type sounds. This is different on the G2 and Reaktor, there one can patch it directly. On the Axoloti one would have to code a special module that would provide for 4 or 6 fm operators in one go, with settable algorithm and all inputs for frequencies and levels. But still you may well experiment with feedback in a delayed setting and this might give different, but nevertheless interesting results. Other block-based system are the VST standard, Jack on Linux, MAX (only there is the Gen level, inside of it), Puredata, Supercollider, Synthedit and all modular synth apps on iPad. Single-sample processing engines are used for Nord Modular, Reaktor and Synthmaker you get with FL Studio ( I'm not sure about future Bitwig 2.0). In short, to make single-sample processing efficient in a modular setting, one needs to compile to machine code patches on the fly, this is hard to do on an embedded processor due to program size restriction (the only exception here seems to be Micropython, which i would love to have running on the Axoloti platform). Apple does not allow to execute code generated at runtime for security reasons.

EDIT:
I just realized that with the Axoloti, patching and compiling is done in the Patcher that runs on a PC, so this could work in principle, but only if the effort to handle this properly would be made by Johannes. It's a lot of work if a system is not designed for this.

I would possibly be interested to code a module with 4 fm ops for Axoloti like DX9, DX21, old soundcard chips, but unlike these with a full matrix 4x4 of modulation levels, this would be more versatile than with only a limited number of fixed algorithms and may still be doable. There are open-source emulations like Dexed VST synth I could use as a starting point.

Marcus

#10

Integrating different (smaller) blocksizes (down to single sample processing) is certainly on my radar, but a long term effort.
I'm not completely sure, but I believe the G2 does 4-sample blocks.

#11

Hello! :smile:

I once owned a G2 rack and I'm sure it it is single-sample. You can just feed back a signal back into a mixer or crossfader and immediately get a proper 6db low-pass filter, for example. It is using Motorola DSPs, block processing does not give much of sn advantage there. Ah, I know what you mean, it has red and blue signal patching, one is single-sample 96 kHz, the blue cables only a quarter for modulation purposes. So you only get one modulation value for 4 audio samples, which provides for some interesting problems, otoh all modules will be converted to whatever processing granularity is needed. For FM feedback you would use only red signals.