Low-Pitch Audio Compression for Harmonic Bass Enhancement
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Solution Overview
Problem
Conventional audio equipment struggles to enhance low-pitch registers of audio signals in small-size speakers without distorting waveforms, especially in low-functionality AV amplifiers that cannot handle high processing loads.
Innovation Solution
An audio signal processing device with a filtering part to extract low-pitch signals, a dynamic range compression part using time-variant gain to compress and amplify these signals, and an adder to incorporate harmonics, reducing processing load and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If harmonics are added to audio signals to enhance low-pitch sound, then low-pitch register enhancement is achieved, but waveform distortion increases and processing load increases
Solution Approach 1:
The audio signal is segmented into multiple frequency bands using band-pass filters, with specific focus on low-frequency components (e.g., 20-200 Hz). By processing only the relevant low-frequency segment rather than the entire audio spectrum, the system achieves low-pitch enhancement while minimizing processing load and avoiding unnecessary distortion in other frequency ranges.
Solution Approach 2:
Dynamic range compression is applied selectively to specific frequency bands (low-frequency components) rather than to the entire audio signal. This localized processing enhances low-pitch registers while maintaining the original quality of other frequency components, thereby reducing overall waveform distortion.
2Reliability
If harmonics are added to audio signals to enhance low-pitch sound, then low-pitch register enhancement is achieved, but processing load increases
Solution Approach 1:
The system extracts only the essential low-frequency components (20-200 Hz) from the audio signal using band-pass filters. By taking out and processing only this specific frequency range rather than the entire audio spectrum, the processing load is significantly reduced while still achieving effective low-pitch register enhancement through dynamic range compression.
Solution Approach 2:
Instead of applying complex harmonic generation to the entire audio signal, the system applies partial action by focusing dynamic range compression only on the low-frequency components. This selective approach achieves sufficient low-pitch enhancement without the excessive processing load of full-signal harmonic synthesis.
3Reliability
If a high crossover frequency is set for small-size speakers, then low-pitch reproduction capability is improved, but the ability to reproduce lower frequencies is lost
Solution Approach 1:
Dynamic range compression acts as an intermediary process that modifies low-frequency components before they reach the small-size speakers. By compressing the dynamic range of extracted low-frequency signals, the system enables these speakers to reproduce lower frequencies effectively without requiring them to physically handle the full power of low-pitch signals, thus extending their reproducible frequency range.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances low-pitch registers with minimal waveform distortion, allowing for efficient processing of multichannel audio signals and improved audio sensation without overburdening the system.
Implementation Method 1
an adder that adds the compressed signal to the audio signal so as to produce a processed audio signal including harmonics causing a missing fundamental effect
Data Source
AI summary
An audio signal processing device is designed to enhance the low-pitch register of an audio signal by generating harmonics causing a missing fundamental effect with a light load of processing but without damaging an audio waveform. The audio signal processing device includes a filtering part (e.g. a band-pass filter configured of a high-pass filter and a low-pass filter) that extracts a low-pitch signal from an audio signal input thereto; a dynamic range compression part that compresses a dynamic range of the low-pitch signal by use of a time-variant gain relative to a peak of the low-pitch signal, which is detected via a peak hold operation using a predetermined time constant, thus producing a compressed signal; and an adder that adds the compressed signal to the audio signal so as to produce a processed audio signal including harmonics.