Browsing by Subject "acoustics"

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    On-Demand Parity-Time Symmetry in a Lone Oscillator through Complex Synthetic Gauge Fields
    (APS, 2022-11-14) Quiroz-Juárez, Mario A.; Agarwal, Kaustubh S.; Cochran , Zachary A.; Aragón, José L.; Joglekar, Yogesh N.; León-Montiel, Roberto de J.; Physics, School of Science
    What is the fate of an oscillator when its inductance and capacitance are varied while its frequency is kept constant? Inspired by this question, we propose a protocol to implement parity-time (PT ) symmetry in a lone oscillator. Different forms of constrained variations lead to static, periodic, or arbitrary balanced gain and loss profiles, that can be interpreted as purely imaginary gauge fields. With a state-of-the-art, dynamically tunable LC oscillator comprising synthetic circuit elements, we demonstrate static and Floquet PT breaking transitions, including those at vanishingly small gain and loss, by tracking the circuit energy. Concurrently, we derive and observe conserved quantities in this open, balanced gain-loss system, both in the static and Floquet cases. Lastly, by measuring the circuit energy, we unveil a giant dynamical asymmetry along exceptional-point contours that emerge symmetrically from the Hermitian degeneracies at Floquet resonances. Distinct from material or parametric gain and loss mechanisms, our protocol enables on-demand parity-time symmetry in a minimal classical system—a single oscillator—and may be ported to other realizations including metamaterials and optomechanical systems.
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    Relative Sound Localization for Sources in a Haphazard Speaker Array
    (2016) Anderson, Neal; Smith, Benjamin D.; Department of Music and Arts Technology, School of Engineering and Technology
    A rapidly deployable, easy to use method of automatically configuring multi-channel audio systems is described. Compensating for non-ideal speaker positioning is a problem seen in immersive audio-visual art installations, home theater surround sound setups, and live concerts. Manual configuration requires expertise and time, while automatic methods promise to reduce these costs, enabling quick and easy setup and operation. Ideally the system should outperform a human in aural sound source localization. A naïve method is proposed and paired software is evaluated aiming to cut down on setup time, use readily available hardware, and enable satisfactory multi-channel spatialization and sound-source localization.