Abstract: This application relates generally to enhancing immune responses. Such immune responses may be elicited by vaccine administration. Compositions and methods for inducing or enhancing an immune response to an antigen are provided. The compositions and methods are useful for, among other things, vaccine formulation for therapeutic and prophylactic vaccination (immunization) and for production of useful antibodies (e.g., monoclonal antibodies for therapeutic or diagnostic use).

Abstract: A speech recognition system combines content analysis of a signal with directional analysis of the signal to calculate probable contents of the signal and the probability that the contents are as calculated. Content analysis can be combined with independent source direction analysis, consisting of the probable direction of the source and the probability that the source is as determined, to refine the content analysis. The direction analysis can affect either the calculation of the probable contents of the signal or the calculation of the probability that the contents are as calculated. The improved information obtained by combining the content analysis with directional analysis can be used to improve subsequent content analyses or directional analyses.

Abstract: An apparatus for and method of applying a selected range of high frequency acoustic energy to the apical end of the eardrum of an ear canal at a predetermined, substantially absolute sound pressure level at any frequency in the range of interest. The selected range of frequencies is generated at a location remote from the ear canal and the sound pressure level of each frequency is varied at the time of generation in accordance with a calibration function to ensure the frequencies reaching the apical end of the eardrum are at the predetermined sound pressure level.The calibration function is calculated by transmitting an acoustic pulse of broad frequency spectrum into the ear canal, measuring the sound pressure of the transmitted acoustic pulse and reflection thereof adjacent the entrance of the ear canal, and removing from the spectrum of the measured sound pressure the destructive interference effects between the transmitted and reflected acoustic pulses.

Abstract: Variations in the amplitude-frequency response characteristic of a loudspeaker are compensated by a drive circuit in which an audio input signal is summed with a plurality of delayed replicas of the input signal to provide a drive signal for the loudspeaker. The delayed replicas are derived by discrete time filtering. Noise reduction techniques applied to the least delayed of the plurality of delay signals substantially improves the S/N ratio in the drive signal.

Abstract: A sound reproduction arrangement and audio signal delay apparatus suitable for use in such an arrangement, includes, in a listening area, one or more primary sound sources for mono- or multichannel reproduction respectively, and a plurality of secondary sources spaced around the perimeter of the listening area and each providing an acoustic signal corresponding to that from the primary source or sources delayed by a respective and independently selectable delay constant and attenuated by a respective and independently selectable gain constant. Control apparatus is connected with the sound sources to derive a plurality of signals for the respective sound sources from an input signal.

Abstract: A network is described which processes two channel stereophonic sound programs for playback through left, right and center sound reproduction channels. Use of the network allows certain advantages of a three channel program to be obtained from the two channel program. The network delays the left and right channels to give precedence to the center channel information but reduces the level of this information to enable the left and right channels to establish a stereo image.

Abstract: A filter network for use with an acoustic signal reproduction system having at least two, spatially separable, speaker means each capable of reproducing acoustic waves from corresponding electrical signal. The network includes a frequency divider for separating an electrical signal representative of acoustic waves into first and second components, the first component including primarily those audio frequencies, which when acoustically reproduced tend to provide unambiguous binaural phase localization. The second component includes primarily those audio frequencies which when acoustically reproduced tend not to provide unambiguous binaural phase localization.

Abstract: In known audio equalization systems, full room equalization cannot be employed because it introduces undesirable transient effects during the growth stage of a sound field, especially in a large auditorium. The invention seeks to solve this problem by establishing an initial state of the equalizing system giving a reduced degree of equalization whenever a signal commences but which effects a transition to normal equalization within a time typically of the order of some tens of milliseconds.