Abstract: Audio electrical signals are controlled to be provided to a plurality of electroacoustical transducers of an array to achieve directivity and acoustic volume characteristics that are varied with respect to a parameter associated with operation of the array. The controlling of the signals results in a change in the radiated acoustic power spectrum of the array as the characteristics are varied. The change in the radiated acoustic power spectrum of the array is compensated.

Abstract: An audio device has passive radiators that are driven by acoustic drivers. The passive radiators are arranged so that the net mechanical vibration is minimized.

Abstract: A new golf tee that increases the distance obtained on a drive is described. The tee increases driving distance by minimizing the energy absorbed by the tee when it is struck by the golf club. By absorbing less energy from the club head, the new tee minimizes the amount club head speed is reduced at impact, which translates into increased driving distance. The new tee also aids the golfer by providing a structure that allows the golfer to easily and consistently determine the amount the tee has been inserted into the ground.

Abstract: A mechanical system for reducing unwanted vibration of a stethoscope chestpiece, which reduces the signal components of the chestpiece output due to sources of vibration other than internal physiologic processes within the patient's body. The system includes a compliance, a mass, and a mechanical resistance element, which together increase transmission loss of external sources of vibration between their source and the chestpiece transducer. Methods of using such a system are also disclosed.

Abstract: This invention features a sound reproduction system in which both signals of a stereo pair of signals are radiated with a directional radiation pattern having a first order gradient characteristic over the frequency range where interaural time difference cues dominate localization in the human auditory system. The directional radiation patterns have main radiation lobes pointing in different directions.

Abstract: A noise-reducing stethoscope comprising a body sound sensor for placement on a body to detect internal body sounds and output in response an electrical signal, an ambient noise sensor, proximate the body sound sensor, to detect ambient noise and output in response an electrical signal, and a difference comparator for accepting the electrical signals from both sensors and providing in response a difference signal, in which the difference signal contribution from ambient noise is less than the contribution from ambient noise to the body sound sensor electrical signal to cancel noise artifacts in the body sound sensor electrical signal.

Abstract: A loudspeaker system for radiation into the passenger compartment of a vehicle has one or more elongated acoustic waveguides to efficiently transfer sound pressure energy from a loudspeaker driver outside the compartment into the compartment. Preferred embodiments feature two elongated acoustic waveguides separated by the loudspeaker driver mounted on a hard baffle panel. One waveguide has an effective length of one quarter wavelength at the lowest frequency desired to be reproduced by the loudspeaker driver, and the other waveguide has an effective length three times that of the first waveguide. One or both waveguides may be folded upon itself. The loudspeaker system is driven through circuitry providing reduced system response at frequencies that may cause the deflection of the loudspeaker to exceed its maximum limits.