reproducing personal sound zones using a hybrid synthesis of dynamic and parametric loudspeakers
TRANSCRIPT
Reproducing Personal Sound Zones Using a Hybrid Synthesis of Dynamic and Parametric Loudspeakers
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Introduction
— Personalized audio environments in
spatialized zones
— Vehicle cabin entertainment/communication
systems
— Cinema surround sound systems
— Multi-participant teleconferencing
— Individual audio in restaurant/cafés
— Minimum sound leakage between zones
— High acoustic contrast
— Excellent speech quality
— Good speech privacy
Introduction
— Personalized audio environments in
spatialized zones
— Vehicle cabin entertainment/communication
systems
— Cinema surround sound systems
— Multi-participant teleconferencing
— Individual audio in restaurant/cafés
— Minimum sound leakage between zones
— High acoustic contrast
— Excellent speech quality
— Good speech privacy
Room
Multizone Soundfield Reproduction (MSR)(Dynamic Loudspeakers)
— Accurate multizone soundfield reproduction up
to spatial aliasing frequency
— Any arbitrary virtual source soundfield
— Large acoustic contrast between zones
— Spatial aliasing frequency can be solved
analytically
— Little to no multizone soundfield control above
aliasing frequency (proportional to number of
loudspeakers)
— Reduced acoustic contrast above aliasing frequency
Multizone Soundfield Reproduction (MSR)(Dynamic Loudspeakers)
Orthogonal basis expansion
Loudspeaker weights:
Multizone Soundfield Reproduction (MSR)(Dynamic Loudspeakers)
Orthogonal basis expansion
Loudspeaker weights:
Multizone Soundfield Reproduction (MSR)(Dynamic Loudspeakers)
Orthogonal basis expansion
Loudspeaker weights:
Parametric Loudspeaker (PL)
— Narrow directivity and large acoustic contrast at
high frequencies
— No spatial aliasing for wideband speech
(dependent on transducer spacing)
— Steerable beams with parametric loudspeaker
arrays
— Poor low frequency directivity and acoustic
contrast
— Sound pressure of the demodulated signal
limited to ~60dB
— greater harmonic distortion than dynamic
loudspeakers
Hybrid Synthesis of Speech Soundfields
Multizone soundfield reproduction
— Large acoustic contrast
— Capable of high SPL
— Low harmonic distortion
Parametric Loudspeaker
— Large acoustic contrast
— Demodulated SPL suits speech levels
— Low harmonic distortion
— Wideband ~150Hz to 8kHz
— SPL ~60dB (decreasing at higher frequencies)
— Harmonic distortion reduces speech quality
Hybrid Synthesis of Speech Soundfields
— Analytically Derivable
— Zone dependent
— Distinguishes MSR high/low acoustic contrast boundary
— Minimum spectral distortion at crossover frequency
— Spatially dependent crossover frequency
(modal truncation length)
Hybrid Synthesis of Speech Soundfields
— Analytically Derivable
— Zone dependent
— Distinguishes MSR high/low acoustic contrast boundary
— Minimum spectral distortion at crossover frequency
— Spatially dependent crossover frequency
(modal truncation length)
smallest radius encompassing all zones
Hybrid Synthesis of Speech Soundfields
— Magnitude response of crossover filters sums to unity (no spectral distortion)
— Easily computed Butterworth polynomials
— Arbitrary crossover frequency
Hybrid Synthesis of Speech Soundfields
— Magnitude response of crossover filters sums to unity (no spectral distortion)
— Easily computed Butterworth polynomials
— Arbitrary crossover frequency
Hybrid Synthesis of Speech Soundfields
— Magnitude response of crossover filters sums to unity (no spectral distortion)
— Easily computed Butterworth polynomials
— Arbitrary crossover frequency