ChromaDSP has released a free audio plugin designed to enhance the harmonic content of your audio.
HarmonicBoost features polyphonic pitch tracking to boost the signal with harmonically matching content. It uses real-time synthesis of octave and interval shifts and separate interval controls are available for the left and right channel to enhance the stereo field.
A smoothing control regulates the compromise of tracking speed and accuracy. Tracking latency can be compensated in your host software and the plugin displays visualizations to illustrate the boost signal. The interface of HarmonicBoost is fully resizable to your liking.
The plugin comes in VST3 and AU formats for Windows and Mac. It support sample rates are 44.1, 48, 88.2, 96 and 192 kHz.
While you’re over at ChromaDSP, make sure to also check HarmonicReverb, a dynamic reverb that enhances the harmonic content of the signal, also free of charge.