Four Seas
Four-dimensional wavetable oscillator



What is Four Seas?
Four Seas is a four-dimensional wavetable oscillator in Eurorack format. Its four related outputs inspire fun, creative patching, and happy accidents. Four Seas has no screens, no presets, and minimal modes, making it an intuitive and playable instrument. Less RTFM and more music.
Specs
Width:
26 hp
Depth:
40 mm with power cable
Power:
+12 V 220 mA, -12 V 50 mA
Expandability
Input:
i2c input and output ports
Output:
Audio output ports for each output
Software:
Open source firmware and user wavetables
How did Four Seas come to be?
It all started because we wanted a wavetable oscillator that felt less like a computer and more like an instrument. Something deep and expressive, but without a screen staring back at us. When making music, we prefer to navigate by ear, not by eye. This turned out to be a big part of our ethos and our main design driver.
From a walk-in closet in Helsinki, we built Four Seas. It's an oscillator designed to be explored by touch. There are no menus to get lost in — just four independent outputs and an evolving ocean of sound. You don't scroll through it, you move through it. You chart your own course, letting it take you where you need to go.
It doesn't have a signature sound. It doesn't steer you, it moves with you.
How does Four Seas work?

1
Four Seas has controls for coarse and fine tuning, and there's a tuning lock to prevent unwanted adventures in pitch.
2
Four Seas comes with 12 banks, or wave cubes, that you can choose from. You can make your own and load them via the SD card slot on the front. We will release a tool for that soon.
3
Four Seas can track V/oct CV for 10 octaves, and there's a linear FM input with an attenuverter.
4
The pitch of Four Seas can be spread into four individual pitches, sent to the four outputs. Spread mode selects the ratio of the four pitches.
5
X, Y, and Z position controls a point inside the wave cube, and thus the waveform that's sent to the outputs.
6
You can spread the initial point into four individual points inside the wave cube, resulting in different timbres at each output.
7
Four Seas has a switch for smooth or stepped movement when changing the point and spread inside the wave cube.
8
Four Seas has two audio inputs for modulating oscillator phase. You can choose from three different types of phase modulation.
9
Four Seas has four independent but related audio outputs, allowing for flexible and complex patching.
10
Four Seas has two inputs for oscillator sync, one of both pairs of outputs, and you can choose from three oscillator sync types.
11
You can choose from three oscillator modulation types and control the amount of modulation applied to each pair of outputs.
12
Each output pair can also be run at LFO rate, which gives you modulation signals that are musically related to the audio outputs.
Check out some videos of Four Seas
Resources
User guide
You can learn more about the functionality of Four Seas with the English language user guide PDF.
Firmware
The firmware of Four Seas is open source, so you can cook your own version to run on the hardware.
Wavetables
More wavetable sets and a specialized tool for creating your own will be released soon.
What people say about Four Seas
"A sound design dream... a really impressive, mic drop of a module for Ferry Island to bring into the world of modular for a first release"
"A real powerhouse of a sound source"
— Ben Wilson (DivKid), YouTube, October 2025
"A fantastic adventure with plentiful sonic possibilities"
"An inspirational work of art that nurtures creativity through digital technology"
"Concept 6/6 · Sound 5/6 · Price/Performance 5/6"
— Beat magazine Dr. Chelsea Bruno, March 2026
"Superb harmonic spreads"
"An 'essential' oscillator that 'belongs in the big leagues'"
— KR Home Studio (Pierre Esteve) Numero 379, September 2025
"A very beautiful wavetable synthesis module… with virtually endless possibilities of wavetable surfing."
"The real focus is on fun and ease of use."
"Best Buy rating"
— Amazona.de (Heiner Kruse) October 2025
"Gear of the Year 2025"
— Signal Sounds

Our instruments are designed, engineered, and manufactured with love in Finland.
We're proud to have been granted the Design from Finland and Key Flag marks by the Finnish Work association — recognition for Finnish craftsmanship.
