London-based Knobula exploded on the scene just a few years ago with their first release, Poly Cinematic, an 8-voice polyphonic synth module. It stood out amongst a sea of black with its colorful light blue and pink motif, and even more so with its ease of bringing 8-voice polyphony (and MIDI) to Eurorack. Knobula is at it again, with another 8-voices of polyphony via Pianophonic, a module that focuses on percussive sounds and wavetables—particularly piano, hence the name. While the colorful faceplate is gone—no more pink or blue to be found (actually, there’s a tiny spot of pink under the MIDI input)—Knobula still retains its core focus with Pianophonic, that of bringing complexity and MIDI into Eurorack, while still being easy to grasp, hands on, and without the need for a screen or menu.
A combination multi-oscillator wavetable synthesizer and a 24bit 48Khz sampler, Pianophonic has a very user friendly layout with plenty of space to roam and tweak, and since there are no menus or screens, Pianophonic—like Knobula’s other modules—only has the most important controls on the faceplate. With this type of approach you’re really at the whim of the designer here—it’s all about what they deem worthy for user control—and in Knobula’s case, it really shows their dedication—really, inspiration—to playability and performability, though it’s not without a few peculiarities. Granted, there’s still plenty to tweak and play.
The controls on Pianophonic are well labeled and clearly defined, with many being of the dual function bipolar variety where each side of a knob controls a different feature than the other, and a few also having secondary functions, reached by holding down the Shift button. At the top of the module is an envelope section with Attack, Decay, and Release controls. This refers to the attack phase, the initial percussive hit of an acoustic instrument (Knobula terms this “Hammer”), and there is some quirkiness—more of a detailed-oriented uniqueness, if you will—in the envelope section. First, the Attack control is a bipolar control for controlling both the Hammer and Wavetables and it can be a little confusing if you’re inclined to think of it as a typical attack control in an envelope. If you use it too much towards either side you won’t hear the other, so it’s best to think of it as more of a mix between Hammer and Wavetable, than an attack control. At least it helped me to think of it that way.
The middle section of Pianophonic has a 16-turn Part Selector Control, with which to select your wavetable and hammer bank combinations, a manual trigger, a Start Point/direction control (Forward/Reverse), a Wavetable Mix control to select which wavetable will be the loudest (Sides, Middle, and Even), and a Morph Speed control for control over the wavetable tracking. The three wavetable oscillators (L,R, with one in the center position) are in a stereo spread configuration, to emulate a piano’s three-string hammer action and give some separation to the three sonically, with the L and R sides being the detuned sides. You can give separation tonally/spatially with the Detune control that goes from unison to suboctave with a 5th separation in the middle position. The secondary feature for Detune, Temperament, is for microtonal accessibility and something that I was very happy to see, as while Pianophonic is in some ways a regimented instrument by design, this offers up less conventional, more experimental tuning options.
On top of what Pianophonic already does/has, there’s a great sounding stereo 24 bit reverb, a compressor, an overdrive—which can sound pretty gritty—and a DJ-style bipolar control for a LPF/HPF with resonance. There’s a Voice Mode button to select between Chord and Poly operations, and the aforementioned Shift button to grant easy access to the alternate functions.
You would think that with the name of the module it’s for piano and you’d be mostly right, but Pianophonic comes loaded with not just various piano sounds, but other sounds as well, and you can also load your own sounds into it and store them on the included SD card. Combined with Knobula’s Waveslicer program, where you can make your own wavetables, hammer, and sound banks, you can really customize Pianophonic quite a bit, and while there are no screens on the module itself—a selling point in this case—to get the most out of Pianophonic you’d do well to log some screen time. I really like this approach, of editing/loading off-module and into a computer where it’s easier to do. It doesn’t work for every module, but here it’s implemented well and keeps the focus on playing, not programming once all of the loading/editing/customization is all set up.
Every sampled sound comes with its own preset for an attack (the “hammer”), just like you’d encounter in the real world. What you don’t encounter in the real world that Pianophonic delivers is the ability to assign any hammer to any wavetable, which can make for some really interesting sound and envelope combinations.
As for connectivity, Pianophonic has a TRS MIDI in, a Gate In, Gate Out (which sends a gate signal when a MIDI gate is transmitted), Start Point CV In, 1v/Oct In, and Chord Select CV In. The Chord Select CV In allows you to access any of the 8-chord memory slots and is fun for the math nerds, as you can do the math to figure out how much voltage you need to reach any of the 8 slots (0-5v, so 5÷8 = 0.625v increments for each successive slot). I’m not trying to write a 1/4/5 ragtime hit, so I left my math skills at the door. Actually, I think I left my math skills many doors ago.
The Gate In, Chord Select, and 1v/Oct CV inputs make for an interesting and powerful team. In combination with a gate signal into the Gate Input, you can access and trigger notes from the chord memory, and by modulating the Chord Select and 1v/Oct you can get a myriad of note, chord, and pitch combinations.
With no instruction whatsoever I was able to discover/uncover a vast majority of the functionality enabling me to jump right in, switching through the sixteen factory presets and combinations; a conglomeration of pianos, synths, vox, and even a glockenspiel. Since this is called Pianophonic I was curious as to how good the piano sounds are, and overall I quite liked them. They don’t sound as rich and deep as my Nord Piano 5’s piano samples, but the various samples all sounded nice, especially through the reverb.
Patching it up via MIDI with the Vector sequencer (out of the Expander’s MIDI out) and with the supplied light blue (the color isn’t all gone!) MIDI cable was a breeze. With a little menu work needed on the Vector’s side, gate triggers and note information were instantly transferred and Pianophonic was off and running. Using Pianophonic as a synth voice in this way felt a bit like a magic trick, bringing in a full and dynamic sound to my patch with minimal effort, leaving me to tweak Pianophonic’s parameters by hand to mess with the sound and experiment with wavetable and hammer combinations and the dynamics available. Using a keyboard to control Pianophonic via MIDI was also plug and play, and for that I used a Sequential Pro 3.
One of my favorite uses for Pianophonic was as a drone machine, and this was a wonderful thing. With the Release control fully CW it will drone on, and depending on the sound/sample and with some filtering—and a lot of the reverb—a lush, lingering pad is yours. Tweak the Hammer/Wavetable control and you can have some tuned percussive hits underneath the haze, or get rid of the Hammer and just have a lot of shimmery early morning mist. Another use I quite enjoyed was the opposite of this; milking the hammer aspects, with short, spiky percussive bursts with just a hint of the wavetables coming through. Crank the release and get a tuned pad underneath this percussiveness. I really enjoyed exploring the different textures and sound combinations. The filter sounds great and is really responsive, and the overdrive adds some teeth, and tweaking the Hammer/Wavetable control was fascinating. I really enjoyed the sounds that came installed on the SD card, and though I did come across some digital artifacts at certain settings, for the most part Pianophonic was a total pro, able to handle whatever tweaks I threw its way.
I even gave Waveslicer a shot, attempting to make a usable sample out of a spoken word intro from an old garage rock record. I came up just short in this task, no fault of Waveslicer or Knobula. It’s easy enough to navigate the program and load up a sample and create the Hammer WAV file, but in order for it to work it’s necessary to make a WAV file saved in 2048 format for the wavetable and I have no experience in this realm and just didn’t have time to dive in and learn it, though I’m hoping to eventually.
Pianophonic really is designed as a MIDI instrument as most of the features can be routed via MIDI CC messages, very much in contrast to the few CV inputs. Even though it is a Eurorack module, it isn’t designed to interact so much with other Eurorack modules as it is with other MIDI modules and devices. It would be nice to be able to modulate the filter cutoff via CV as well as subtly modulating the Detune and the Morph speed, among other parameters with CV and not just MIDI. Even though I do understand that Pianophonic’s true operation is as a polyphonic MIDI standalone synth in a Eurorack module—and it’s really powerful in that regard—a few more CV ins, maybe even one that’s assignable, would be great.
I’m starting to think that maybe Pianophonic is my call to arms to get more MIDI controlled/controller modules in my setup. I’ve made some pretty great music with it (I like to think) and have had a lot of fun experimenting. There is really no limit to what you can morph, drone, and strike and I don’t think there’s anything on the market that comes close to what this has on offer, definitely not in a Eurorack module. Pianophonic is incredibly powerful and malleable module with great performability and sound, adding a lot of polish and shine to my patches. This one you really need to experience firsthand.

Price: $449
knobula.com