Hivetune has released Delta6, a free six-operator FM synthesizer for macOS and Windows.
FM synths can look quite intimidating when they put every operator and routing control in front of you at once. It took me some time before I even considered learning to program FM synths back in the day, and I’m still not very good at it.
Delta6 is definitely a capable instrument, but the layout makes it look far more approachable, so it’s actually a nice way to get into FM synthesis.
I like the interface design. The layout and colors give me an old FL Studio vibe, and the overall look definitely helps reduce that FM intimidation factor.
The main difference between Delta6 and a traditional FM synth is its open modulation matrix. Instead of selecting from a fixed list of algorithms, you connect the six operators using 15 modulation dials arranged in a triangular grid.
Modulation flows from higher-numbered operators to lower-numbered ones. Glowing arrows help you visualize the active paths, while color coding shows whether an operator is working as a carrier or modulator. You can click a matrix dial to switch it directly to 0% or 100%, or drag it for finer control.
Each operator has its own waveform, ratio, fine-tuning, level, and ADSR envelope. The available shapes are sine, triangle, saw, square, and noise, so Delta6 can do much more than the clean sine-wave tones commonly associated with classic FM synthesis.
Operator 6 also has a feedback control that can push a sine wave toward a rounded saw-like shape and eventually into more chaotic territory. The engine supports up to 16 voices, plus a monophonic legato mode with adjustable glide.
Drift adds analog-style pitch variation across the operators. Delta6 also includes velocity sensitivity, a reverb, and three chorus modes inspired by classic 1980s bucket-brigade circuits.
The dice button gives you a fun way to experiment with FM synthesis without actually doing the dirty work. Instead of randomizing everything blindly, it chooses a pad, pluck, keys, or lead archetype and generates suitable ratios, envelopes, and routing as a starting point.
We’ve had a few interesting free FM synths recently, including Sender Spike’s SN Zero and the TetraOP and Ouranos7 instruments covered in our KVR Developer Challenge synth roundup. Hivetune previously gave us the excellent Relica 2 chiptune synth.
The free Delta6 edition is fully featured and includes 20 presets. There’s also the $4.99 Complete Edition, which expands the factory library to more than 100 presets.
The free checkout is super quick. Click Get It, enter your email address, and the download link will appear immediately on the next page. Be aware that this also subscribes you to Hivetune’s newsletter.
Delta6 runs as a VST3 plugin or standalone app on 64-bit Windows 10 and newer. It supports VST3, AU, and standalone formats on macOS 11 or newer, with native Intel and Apple Silicon compatibility.
Download: Hivetune Delta6 (FREE)
Deal of the day 🔥: Get the VATRA mix finisher plugin by Flame Sound!More:
- Hivetune releases Relica 2, a FREE 8-bit synthesizer plugin
- Check out some FREE synths from the KVR Developer Challenge 2026
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Last Updated on September 2, 2026 by Tomislav Zlatic.
