Abstract: The present invention involves a method for dynamically adjusting the spectral content of an audio signal, which increases the harmonic content through the systematic introduction of amplitude asymmetry. The present invention also involves an apparatus for dynamically adjusting the spectral content of an audio signal which consists of a constant current source, an input buffer amplifier, an output buffer amplifier and a progressively biased system of bipolar junctions, which will produce a controlled asymmetry of the transfer characteristic.

Abstract: A measurement system and method combine an audio announcement system with a plurality of spaced apart wirelessly coupled devices which evaluate speech intelligibility of audio output from loudspeakers of the audio announcement system. Processing can take place at some or all of the devices as well as at a common control element. Evaluations can be based on use of a method which maps to a Common Intelligibility Scale.

Abstract: A system for selectively acquiring, processing and displaying 3-D waypoints in a manner suitable for the purpose of providing selected hands-free navigation guidance to a user. The system includes a plurality of multi-function devices for defining a frame of reference, at least one of the plurality being adapted to be carried by the user. A communication link provides communication between the plurality of multi-function device means to form a mesh network. The multi-function devices calculate, exchange and process waypoint information indicative of the location of itself, the device carried by the user, and at least one other the device means to thereby provide the route taken by the user. A display gives a 3-D navigation guidance to the user.

Abstract: A method for dynamically adjusting the spectral content of an audio signal, which increases the harmonic content of said audio signal, said method comprising translating an encoded digital signal into data bands, creating a psychoacoustic model to identify sections of said data bands that are deficient in harmonic quality, analyzing the fundamental frequency and amplitude of said harmonically deficient data bands, creating additional higher order harmonics for said harmonically deficient data bands, adding said higher order harmonics back to said encoded digital signal to form a newly enhanced signal, inverse filtering said newly enhanced signal, and converting said inverse filtered signal to an analog waveform for consumption by the listener.

Abstract: An electronic circuit for dynamically adjusting the spectral content of an audio signal. The circuit includes a constant current source, a output buffer amplifier and a biased inductor for introducing controlled amplitude asymmetry. This apparatus thus can be arranged to process an audio signal so as to introduce a predictable and controllable harmonic distortion that is negligible at small signal amplitudes and increases progressively at larger signal amplitudes.

Abstract: A method of optimizing the low frequency audio response emanating from a pair of low frequency transducers housed within a cabinet. The low frequency transducers are electrically connected to a power amplifier and source of audio content. The resonant frequency (Fs) and amplitude (Q) are characterized as to the high-pass pole of the low frequency transducers as they are mounted within the cabinet. An equalizer is placed between the amplifier and source of audio content for canceling the complex pole of the low frequency transducers and for establishing a new complex pole as a cut off point in which no low frequency sound would be generated by the low frequency transducers.

Abstract: An audio transducer for use in a loudspeaker system. The transducer includes a rigid base, a pair of flexible, curved diaphragms and each diaphragm having a distal end and a proximal end. The curved diaphragms form hemi-cylindrical lobes being substantially tangent to one another at their proximal ends and are attached to energy absorbent dampers at their distal ends. The transducers can be employed in a line array as part of the loudspeaker system as well as some of the transducers facing forward while others rearward and, in doing so, their amplitudes and phases can be adjusted for fine tailoring the geometric coverage of acoustic energy radiating from the loudspeaker system.