Acoustic Beamforming for Guitar Amplification: Directional Steering & Spatial Coverage Optimization

Abstract

Conventional electric guitar amplifiers radiate sound omnidirectionally, producing uneven loudness across spaces and causing excessive acoustic spill. This thesis investigates the feasibility of applying acoustic beamforming to a speaker array for guitar amplification, and explores an alternative application when the original directional goal proves physically unachievable. A theoretical framework based on the array factor formulation for a uniform linear array is developed and validated through several Python simulations. These simulations reveal fundamental constraints: side lobes from finite array size and grating lobes from the half-wavelength spacing requirement make precise directional control physically impossible for broadband guitar signals since no fixed element spacing can satisfy the spatial Nyquist criterion across all frequencies simultaneously. This finding motivates a reframing from directional steering to spatial uniformity, using array interference properties to distribute sound evenly across a room rather than focusing it in a particular direction only. This spring portion repurposes Sionna RT, a ray tracing library originally meant for radio-frequency simulation, to acoustic simulation at 440 Hz. A coverage metric combining mean signal strength (path gain) and spatial standard deviation is defined, and two different strategies are compared: a single-lobe exhaustive sweep versus a greedy multilobe search over four simultaneous beam directions. The optimized single-lobe configuration reduces spatial standard deviation from 5.29 dB to 2.91 dB compared to a naive baseline, while the multilobe configuration achieves 2.66 dB, an even greater improvement. These results demonstrate that beamforming, while unsuitable for directional guitar amplification, offers a viable mechanism for improving spatial coverage uniformity.