Isivisi Audio has released SLURP, a free spatial rotation synthesizer for macOS, Windows, and Linux.
SLURP blends FM synthesis with a novel approach to oscillator movement. Instead of traditional waveform-based sound generation, it creates sound from three rotating oscillators in 3D space.
At first glance, I thought the SLURP was going to be hard to get into. But it’s one of those instruments where once you dig in, it’s surprisingly welcoming even if you don’t fully understand how it all works.
The GUI may look different from typical synths, but it’s intuitive enough to encourage experimentation, even if you have no idea what quaternion oscillation actually means (hi, friend!).
The free version of SLURP provides a solid starting point without feeling like a demo of paid software. You get the standalone app, VST3, and CLAP plugin versions, along with one voice of polyphony and a selection of built-in oscillators like sine, saw, square, and phasor.
From there, you can assign one oscillator to each axis (X, Y, Z) and sculpt movement through rotation, influence, intensity, and phase controls.
You can check out the old modular version of the instrument in the video below.
The colorful visualizer in the middle of the interface shows the composite rotation path in real time. This is not just meant for eye candy. It’s super helpful for understanding what the knobs actually do to the sound as you adjust the value.
Despite the unusual concept, SLURP didn’t overwhelm me on first use. Controls are logically grouped, and common synthesis elements like ADSR envelopes, macros, and modulation targets are all easy to access.
Even the custom projection axis, which lets you change your listening “camera” angle, feels intuitive and creative rather than technical.
If you want to take things further, the paid version (available for $28) unlocks all 16 voices, additional oscillator types like noise and audio input, full modulation functionality, and lifetime updates.
That adds quite a bit of depth, especially since you can modulate nearly everything inside the synth, from stereo width to oscillator influence. The extra oscillator types, like Noise with fractal and cellular options, are worth it if you’re deep into sound design.
That said, the free version is packed with potential. I played it for a couple of hours over the weekend, and it’s excellent for building motion-heavy pads, evolving leads, and textures.
I loved how SLURP invites you to approach synthesis differently, and you don’t have to understand the math behind it. In the end, I always have the most fun with plugins when I just tweak, rotate, and listen until I get something I like.
SLURP is available now in VST3, CLAP, and standalone formats for Windows 8+, macOS, and Linux (Intel, AMD, and ARM).
No registration is required to download the free version. Visit the product page and click the Steal Now button to get the free version (though I’m not a fan of the label).
Download: Slurp
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Last Updated on August 18, 2025 by Tomislav Zlatic.
