So let’s start with the oscillators. All of them (the two main and four subs) are independently tunable. The frequency of the subs is determined by taking the frequency of the main oscillator and dividing it by a number from one to 16. When the knobs are turned all the way to the right, they’re in unison with the main oscillator. As you turn them counterclockwise, they generate different subharmonics. Most subs simply play the same note an octave or two lower. So in short, these sound different because math. 

This also means that you can use the Subharmonicon to “play” six-note chords with a single press of a button, or key if you connect an external controller. So even though it is in theory a two-voice paraphonic synth, you can get some complex sounds out of it.

You can tune the oscillators in a completely unquantized mode if you feel like exploring the world of microtonal music. Those of you with more-traditional tastes will be happy to know that there are four different modes of quantized tuning. There are twelve- and eight-note versions of both equal temperament (the standard for modern Western music) and just intonation. And you can set the range of the sequencer knobs to be plus or minus one, two or five octaves from the oscillator’s frequency. Picking plus or minus five will give you a total of 10 octaves to explore. This is at the expense of accuracy, since you’ll now have 120 notes to choose from as opposed to 24 in one-octave mode.

There are also three options when it comes to wave shapes: square, saw or a combination of a square main oscillator and sawtooth subs. That gives you access to not only classic Moog bass but also brassier tones and rich multitimbral sounds. Using the patchbay, you can also feed one oscillator into another to create metallic FM tones, a noise source or modulate the pulse width of the main oscillator, which is great for adding a bit of dissonance or warbling your sound.

This is all to say that while the name and spec sheet might lead you to believe this synth is all about the bass, it’s capable of a wide range of timbres. In fact, within an hour of unboxing the Subharmonicon, I was coaxing some rather lovely pads out of it. And with a little clever patchbay work, you can even get some solid drums.

When I eventually figured out how to get some respectable percussion sounds going (it took a couple days), I was pretty excited, in large part because of the potential for pairing them with the sequencer. Or should I say sequencers. There are two of them: one for each of the oscillators. At first glance it might not seem like much — a pair of four-step sequencers — but this machine has a lot of tricks at its disposal. 

Terrence O’Brien / Engadget

The most powerful tools are the rhythm generators. Similar to the sub oscillators, these divide the master tempo by a number from one to 16 and then apply that to the sequencers to create polyrhythms. All four generators can be applied to sequencer one, two, both or none. This means that even if you’re limited to only four notes, the rhythm at which they play and the way they combine can create long, evolving passages that might not repeat for quite some time.

For an extremely simple example of this, you could set sequencer one to play a four-note progression, stretched out over four bars. Then sequencer two could play a simple arpeggio twice before the bass note changes, creating a shifting harmony that feels much longer than what you could get out of a standard step sequencer. 

Now, it’s important to note that the Subharmonicon is paraphonic — which means the oscillators share a single amp envelope and filter envelope. So when the sequencer triggers one voice, both sound. This means you can’t really have a slowly plucked melody playing over a constantly thumping bassline without some patchbay trickery (or external modules). This is a shame, because being able to trigger the oscillators separately would open up whole new avenues for rhythmic exploration. But there are still plenty of opportunities for them to interact in interesting ways.

Like many synths, the Subharmonicon really shines when paired with some effects pedals. Here it’s run though various combinations of delay, reverb and distortion to show how they can greatly expand its character.

The other major tool at your disposal is the ability to choose which oscillators your sequencers are controlling. By default, sequencer one is for oscillator one and sequencer two is for oscillator two (you can’t use both sequencers to trigger a single oscillator). But you pick whether the sequencer controls the main oscillator, sub oscillator one, sub oscillator two or some combination of the three. When the sequencer is controlling the sub, it’s changing its relation to the main oscillator, not controlling its frequency directly. This can result in some really out-there sounds. You can have the main oscillator chug away while the sub dances around it. Or as the main oscillator changes, the subs can shift the interval they’re playing.

If you’re anything like me, your first instinct will be to get everything going at once: all four rhythm generators triggering both sequencers, which are controlling both the oscillators and their subs, with everything tuned to different intervals. Allow me to tell you right off the bat: This is a terrible idea. While it’s tempting with any new toy to use all of its fancy features, restraint is the key to making the most of the Subharmonicon. It is incredibly difficult to get all six voices to line up in a consistently pleasing manner if you’re using the sequencers to control all of them. Since the voices are all triggered simultaneously, the line between interesting interplay and complete chaos — if you use all four rhythm generators simultaneously — is very, very thin.

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