Korg Volca FM: Firmware 1.08 and All That

This is a quick brain-dump of what I've learned over the past two weeks about the Volca FM.

In my last post I talked about FM synthesis using Dexed. This is great, but it's a VSTi so you have to run it on a computer and I'm somewhat allergic to relying on computers on a gig. In theory the Volca is a cheap-ish solution that can run Dexed patches on hardware without fussing with a computer, but there are a few challenges.

Here's a video with instructions on loading Dexed patches into the Volca -- you'll just need a computer running Dexed hooked up to the Volca via 5-pin MIDI:

The MIDI In port means that when you're not loading up new patches you can hook up a proper keyboard and stop poking at the tiny toy one on the Volca. Because it's just FM synthesis, it will play any pitch you like so it copes just fine with a seven-and-a-half-octave piano keyboard. This already opens up the possibilities of its patches pretty radically, although in many cases they work best in a smaller range than that.

I've had no problem running the headphone out into a chain of guitar pedals, which can very dramatically buff up the sound. After all, there's no onboard reverb or delay, the built-in chorus is weak and a LP filter can tame the Volca's tendency to make popping sounds. Just start with the volume off and inch it up until it sounds right, as the headphone signal is of course a fair bit hotter than a guitar pedal usually expects.

Firmware 1.08

[CAVEAT: This section is as correct as I can make it at the time of writing, in November 2019. Things may change in the future. As always, unsupported firmware made by a stranger on the internet is installed at your own risk, but so far reports have been positive and you should be able to go back to Korg's official version if you run into problems.]

The latest Korg firmware release is 1.07, which was released in September so really only a few weeks ago.

However, in a few weeks ago /u/pajen announced on Reddit that s/he had decompiled the FM's firmware and made some additional enhancements and bug fixes, calling it version 1.08. At the time of writing the link posted on Reddit was down but the files are available at Ranzee's site.

(I debated whether to mirror them here, but this is a quickly-changing situation and I don't want my copies hanging around if they go stale and a better version comes out or an issue is discovered. I expect updates will be reported on this Gearslutz thread and/or on Reddit so check there for the latest and greatest.)

Panjen's update is, in my opinion, well worth installing and I hope is leads to a community project to make hacking the FM a bit more accessible. I would love to get involved, but I have no practical experience with assembler and don't have the time to learn it from the ground up. But the potential here is pretty great for such a cheap little box.

For me, the highlights are the new global settings, all of which are off by default (this leaves your Volca behaving the same way it did before the update). These can be changed by booting up the Volca while holding down Func, then turning the corresponding numbered lights on and off with the mini keyboard, then hitting "Rec" to save:

  • Setting 9 turns MIDI note velocity on and off. This was my main reason for installing the patch. I can't imagine why anyone would want to play a keyboard with one hand and ride a slider with the other to control velocity; I do get that some people might just want to use the built-in keyboard but I'm not one of them.
  • Setting 10 improves compatibility between the Volca and programs like Dexed that output DX7-compatible SysExes. This is great as previously I was getting some pretty poor matchups between a patch made in Dexed and the same patch once installed in the Volca. I haven't tested this much yet and I'm sure it's still not perfect but I'll take any improvements I can get.
  • Setting 11 allows a note to ring out while you change patch, without affecting the patch of the ringing note. I don't know why anyone wouldn't want that.

So, obviously, I have all three of these permanently enabled. Note that the Volca seems to benefit from a harder velocity curve than I'd usually choose but that might be just my controller, the patches I've experimented with or my playing style.

There are also some bug fixes to the LFO and some extra MIDI CC messages. I haven't explored the latter much because the Volca is still something I'm just playing with, but if and when I want to set it up for a performance it will be massively useful to be able to send a batch of CC messages from my main controller to change patch, sequencer pattern and mod wheel behaviour. There's also CCs for the built-in chorus but I'm personally not a fan of it so it tends to always be off.

If you haven't done it before, I recommend updating to Korg's official firmware first. I'm not sure very much can go wrong but it will give you a feel for the process and if you do something wrong, Korg's customer support should be able to sort you out. Once you're familiar with the process, the 1.08 version installs in exactly the same way. If you get a "Decode Error", check your cables are all OK; on my laptop I had to turn the volume to about 50% and it wouldn't accept it at full blast.