ChromaDSP Releases FREE Harmonic Boost VST3/AU Plugin


ChromaDSP offers its new Harmonic Boost effect as a freeware VST3 and AU plugin for digital audio workstations on PC and Mac.

Harmonic Boost was created using iPlug2, a free to use framework for building cross-platform audio plugins. ChromaDSP is a one-man-band as far as I can see, so before anything else, I should say that I appreciate someone putting the time in to develop tools to help us make music.

When you think of harmonic enhancers, you think of adding warmth to your sound. You think of moving away from the digital sound towards something more analog-like (like our free BPB Saturator). Harmonic Boost isn’t just about adding color; it’s also about dialing in some very specific overtones that can change the overall feel as dramatically as you like.

The plugin itself is simple yet ambitious. On the one hand, the GUI appears to be as no-frills as it gets. On the other hand, it has a couple of features that it didn’t need to have. I don’t mean that in a negative way; that’s why I say it’s ambitious, especially for version 1.0.

Going through the GUI, we start with the highpass and lowpass filters that let you focus on a narrow or wide frequency range. Next is tracking/smoothing, which adjusts the speed and accuracy of pitch tracking.

If you are the experimental type, with sounds that evolve like a sweeping pad, a short tracking time can create rapidly changing harmonics. Tuning by default is set to 44oHz (A4), and messing around with it can add subtle tension or complete carnage.

You get separate interval control over the left and right channels to enhance the stereo field and produce dissonant or consonant combinations. Octave shift allows you to offset by up to plus or minus four octaves, as well as various stages between octaves. If you are having any lag issues, a drop-down menu is available for compensated latency.

Finally, the GUI finishes with a nice visual representation of the harmonic boost. There are many ways to use Harmonic Boost; one option is to let a subtle, two-octave up, harmonic ring out as you’d maybe do when programming strings. Another, less useful way is to drop two octaves, crank everything, and you’ve got some instant Hammer Horror vibes.

It’s a fun initial release, and I think there’s more to come in future updates with Harmonic Boost. The software is available in VST3 and AU plugin formats for 64-bit hosts.

Download: Harmonic Boost (3.2 MB download size, ZIP archive, 64-bit VST3/AU plugin format for Windows & macOS)

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About Author

James is a musician and writer from Scotland. An avid synth fan, sound designer, and coffee drinker. Sometimes found wandering around Europe with an MPC in hand.


  1. hmmmm, great idea, unfortunately used on the type of sound that most people would need help with: bass, its just too slow to keep up. It’s more of a pitch tracking sine synthesiser than a harmonic booster. Anything remotely fast or rhythmic you want to boost just ends up ringing or late.

    File under creative / experimental not mix utility.

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