Educational Acoustics Audio System for Experiential Learning of Resonance Through Sensor-Based Spectrogram Visualization

Understanding resonance and frequency behavior is fundamental in engineering acoustics and in technology-supported music-learning environments. This work presents an Educational Acoustics Audio System (EAAS) designed as a sensor-based hardware–software toolkit that enables experiential learning of acoustic resonance through listening, spectrogram visualization, and analytical modeling. The system integrates a bass-reflex loudspeaker with interchangeable vent configurations, a microphone-based sensing module, automated spatial sampling, and a MATLAB interface for generating logarithmic sweeps, recording responses, and computing high-resolution spectrograms. The instructional design is grounded in the Educational Acoustics Conceptual Framework (EACF), originally proposed by the authors, which structures learning through concrete, graphical, and abstract levels. Learners first explore perceptual changes in low-frequency amplification, then interpret time–frequency patterns using spectrograms, and finally compute Helmholtz-based resonance frequencies based on physical parameters. Experimental measurements collected at multiple microphone distances reveal stable resonance peaks at approximately 546 Hz (full vent) and 265 Hz (half vent), alongside consistent amplitude differences between vent configurations. By integrating auditory perception, sensor-based acquisition, and mathematical modeling in a unified and low-cost system, the EAAS provides an effective technological platform for hands-on exploration of resonance and frequency response. This approach strengthens conceptual understanding in engineering acoustics while supporting its application in related educational contexts.