Design of Differential Loudspeaker Line Array for Steerable Frequency-Invariant Beamforming

Area of Science:

• Acoustics
• Signal Processing
• Array Signal Processing

Background:

• Differential beamforming offers frequency-invariant beampatterns with high directional gains using small apertures.
• Loudspeaker line arrays have been used for broadside frequency-invariant radiation patterns.
• Steerable frequency-invariant beampatterns for loudspeaker arrays remain an underexplored area.

Purpose of the Study:

• To propose and validate a method for designing steerable differential beamformers for loudspeaker line arrays.
• To achieve frequency-invariant beamforming with directional control across a range of frequencies.

Main Methods:

• Determining target differential beampatterns based on desired direction, main lobe width, and beampattern order.
• Transforming target beampatterns into the modal domain for representation.
• Utilizing Jacobi-Anger expansion for beamformer design.
• Formulating a multi-constraint optimization problem to find optimal weighting vectors, balancing robustness and mean square error.

Main Results:

• The proposed method successfully designs steerable differential beamformers for loudspeaker line arrays.
• Simulations and experimental results confirm the achievement of frequency-invariant beamforming.
• The system operates effectively across a frequency range of 300 Hz to 4 kHz.

Conclusions:

• The developed method provides a viable approach for creating steerable frequency-invariant beam patterns in loudspeaker line arrays.
• This advancement opens new possibilities for directional audio control and enhanced acoustic experiences.