VST3 Plugin pro úpravu sub-basových frekvencí na základě vnímané hlasitosti lidským uchem

This bachelor’s thesis addresses one of the most persistent challenges in modern audio production, the accurate management and reproduction of the sub-bass region (20 Hz to 60-80 Hz). Due to the non-linearity of the human auditory system which is described by the Normal equal-loudness-level contours (ISO 226:2023), humans are significantly less sensitive to these low frequencies than to the midrange, leading to a critical disparity between measured loudness and subjectively perceived loudness. The theoretical part of this work examines the human auditory system and the specific characteristics of the sub-bass region, investigating psychoacoustic phenomena, such as the ”missing fundamental”, that govern how humans interpret low-end frequencies. The research evaluates existing static and dynamic mixing workflows, including combination of these workflows, reinforcing that even these standard methodologies are effective for maintaining consistent perceived loudness across the sub-bass spectrum when rightly calibrated to human hearing sensitivities. The practical outcome of this thesis is the design and implementation of a VST3 plugin developed using the JUCE framework and C++, that can run on all major operating systems and DAWs. The plugin utilizes a two-stage signal chain, a static equalization stage based on equal-loudness curves and a frequency-aware saturation stage to generate harmonic overtones. Qualitative feedback from musicians and audio engineers confirms that the tool can provide a perceptually accurate results, but that there are still a lot of variables the plugin can not control. Despite these challenges, initial feedback suggests the plugin represents a step in the right direction for addressing the gap between objective signal intensity and human hearing sensitivity and that the plugins potential use can go beyond equalizing sub-bass frequencies. Performance testing indicates a higher computational demand than standard stock plugins, identifying a key area for future optimization.