Unlike many measurement systems that use a notch filter to measure distortion and noise, SoundCheck utilizes a proprietary algorithm that measures the distortion separate from the noise. HarmonicTrak can measure any number of harmonics simultaneously including sub-harmonics.
With its advanced filtering algorithms, HarmonicTrak excludes the contribution of the fundamental and the noise in between the harmonics (vertical red lines). Thus harmonic distortion, including high-order harmonics present in rub & buzz, are measured accurately and not buried in background noise.