Xfer Records Cthulhu Chord Plug-In

June 13, 2013

Steve Duda’s plug-ins are some of the biggest secret weapons in modern dance music production. His LFO Tool—which was originally designed for Deadmau5 as a software-based control voltage generator—has morphed into one of the coolest resources for ultra-detailed sidechain effects. His drum machine, Nerve, has found its way into countless tracks thanks to its unorthodox yet intuitive approach to designing grooves. Last winter, he unleashed his latest software gadget upon the electronic and dance music communities. Cthulhu looks to do for harmony what synthesizers have done for sound itself, and we think it has applications reaching far beyond “EDM.”

What Is It?

On the surface, Cthulhu is a plug-in MIDI device (AU on Mac and VST on Windows) that puts hundreds of classical music themes and chord progressions at your fingertips. You can audition a cornucopia of chords by playing single notes, coming up with progressions that you might never have imagined otherwise. In Duda’s words, “Cthulhu can provide great inspiration to even the theory masters, preventing us keyboardists from falling into familiar ‘motor-memory’ chords and instead helping us navigate through time-tested progressions with physical ease.”

Some critics have used the dreaded word “cheating” in reference to Cthulhu, but that’s missing the point because once upon a time, drum machines, sequencers, quantization, and even synthesizers themselves were considered cheating. That’s obviously no longer the case. Right? [Keyboard is in favor of any technology that invites people to discover and play music. Cheating is when someone uses that technology as a shortcut to a prize like money or fame and doesn’t actually care about getting good. In other words, we love Cthulhu as long as you love craft. —Ed.]

Chord Mode

Cthulhu works in two basic modes: Chord and Arpeggiator. In chord mode, you can select from a few hundred presets that contain classical progressions from Bach’s legendary chorales, along with Beethoven, Liszt, Mozart, Debussy, and many other composers. Load in a preset and each MIDI key becomes a different chord from a given piece by the selected composer, some with extremely wide, open voicings; others with more clustered notes.

From there, you simply play individual notes from across the keyboard range and decide which of the resulting chords you like. Since there are countless permutations within a single preset, you can operate without preconceptions, creating chord progressions that you most likely wouldn’t have composed yourself. After all, every keyboardist has keys, modes, licks, and voicings that they fall back on when first approaching their instrument. Cthulhu bypasses those habits and preconceptions, letting you choose harmonic progression based on what sounds inspiring in the moment. 

Even if you stick exclusively with the onboard presets, Cthulhu really does feel like magic. And in some ways, yes, like “cheating.” But if you dig a bit deeper, you can also create your own presets by simply turning on Cthulhu’s Learn mode and assigning your own favorite chords to each of the keys, then saving the results. Of course, you don’t need to play the chords in the same order as the original composer put them—you can rearrange and deconstruct at will. If you already have some training in music theory, Cthulhu isn’t going to replace it—it’s going to enhance it.

While Cthulhu works with a fairly wide range of sequencers including Logic (albeit with a lot of bizarro IAC fiddling in Logic’s case), it’s especially easy to integrate into Ableton Live. This brings us to another interesting application of the plug-in. By using Live 9’s new “Convert Harmony to MIDI” feature, you can extract chord progressions from any audio file, then use Cthulhu’s advanced Learn features to convert the resulting MIDI file into yet more presets based on the songs you dig. This makes for a powerful tool for remixers.

Arpeggiator Mode

The chord tools alone are worth the price of admission, but Duda doesn’t stop there. There’s also an extremely powerful arpeggiator, waiting to take those clever chord progressions and make them bubble and percolate. Naturally, Cthulhu’s arpeggiator includes all the usual up-down modes, with a few intelligent variations similar to the options in Ableton Live’s arpeggiator tools. But that’s where the similarities end, since Cthulhu’s arpeggiator folds in an array of amenities normally found in step sequencers, but in a unique manner.

For starters, once you’ve selected an arpeggiator mode, each step can be specified as a graph type (that is, you can switch between the various up-down modes on a per-step basis) or numerically, by selecting specific notes in the chord being arpeggiated. While this may sound complicated at first, it’s remarkably intuitive in practice.

From there, you can add randomization on specific steps, which is great for giving your sequences an improvised feel—again, generating patterns that you might not come up with on your own. What’s more, if you’ve got Cthulhu set up to send data to a different MIDI track, you can record that data on the fly, letting Cthulhu happily chug along while you sip coffee and wait for a nifty riff to appear. Afterward, you can sift through the MIDI recording and pick your favorite bits for further editing.

Because of all of these features, combined with the way they’re implemented, Cthulhu is also poised to be a powerful tool for teaching music theory. Why? Because whenever you play a chord or arpeggio, a clever little graphic of Cthulhu himself tells you what chord you’re playing via a  thought bubble. So if you want to crack a book or take a music class, Cthulhu can actually help you understand why you like the progressions and melodic motifs you do.


Some are saying that Cthulhu could be a transformative product, infusing new levels of sophistication to electronic dance music in the coming years. Punditry aside, for 39 bucks, Cthulhu is going to help a lot of musicians of all types overcome their ingrained approaches to performance and composition. To some, that kind of breakthrough is priceless. To us, it certainly merits a Key Buy.

PROS: Massive collection of classical (and thus royalty-free) chord progressions to draw from for inspiration. Complex and deep arpeggiator. Works beautifully with Ableton Live.

CONS: Fiddly, but not impossible, to integrate with Logic. No Pro Tools version, and not compatible with the FXpansion wrapper.

Bottom Line: Fantastic resource for generating innovative chord progressions and arpeggios.

$39 direct download



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