Listener Specific Audio Reproduction System

Abstract

A system for use with an audio reproduction system that corrects for distortion caused by the system as well as any hearing impairment suffered a listener. Test signals are introduced into the input of the system to produce test sounds that are perceptible by the listener. Using a pushbutton, the listener indicates when a test signal of progressively increasing volume reaches an audible level. The resulting measured values of the listener's threshold of hearing at different frequencies is compared with comparable data for a normal listener to generate correction values that are used to program an equalizer which compensates for not only the listener's hearing impairments but also any distortion produced by system components or room acoustics.

1 . A portable audio player including:
 an audio test signal source for generating electrical signals representative of test sounds of different frequencies and amplitudes to be played to a listener of said portable audio player,   an input device for accepting indications from said listener indicating said listener's perceptions of said test sounds, and   a processor for processing said indications to create gain control values and for adjusting the frequency response of said portable music player based on said control values.   
     
     
         2 . A portable audio player as set forth in  claim 1 , wherein said processor is a microprocessor or digital signal processor. 
     
     
         3 . A portable audio player as set forth in  claim 1 , further comprising a display screen for displaying instructional prompts. 
     
     
         4 . A portable audio player as set forth in  claim 1 , adapted for delivering said electrical signals to at least one headphone for producing said test sounds. 
     
     
         5 . A sound reproduction system with automatically programmable apparatus for adjusting the frequency response of said system, said reproduction system including a source of audio frequency electrical signals and at least one electronic amplifier, said amplifier having an input connected to receive said electrical signals from said source and having an output adapted for connection to a transducer to produce sound waves corresponding to said electrical signals, and said system further comprising:
 an electrical audio test signal generator connected to the input of said amplifier to produce a sequence of different test sound waves that differ as to volume, frequency or both,   an input device for accepting indications from a human listener indicative of the perceived intensity of at least some of said different test waves as perceived by said listener,   a processor responsive to said indications for translating said indications into a plurality of control values, and   an adjustable equalizer connected between said source of audio frequency electrical signals and the input of said amplifier, said equalizer being coupled to said processor to receive said control values and preferentially amplify said electrical signals at different frequencies in accordance with said control values.   
     
     
         6 . A sound reproduction system as set forth in  claim 5  wherein at least selected ones of said audio test signals produced by said test signal generator have an intensity that progressively increases over time and wherein at least some of said indications from said listener indicate the times at which the sound waves produced by said selected ones of said audio test signals are first perceptible by said listener. 
     
     
         7 . A sound reproduction system as set forth in  claim 5  wherein said processor translates said times into intermediate values indicating the lowest sound level perceived by said listener at particular frequencies and wherein at least some of said control values are related to the difference between said intermediate values and the lowest sound level which is perceptible by the average person at said particular frequencies. 
     
     
         8 . A sound reproduction system as set forth in  claim 5  wherein at least some of said control values are related to the difference between the lowest sound level perceived by said listener at particular test sound frequencies and the lowest sound level which is perceptible by the average person at said test sound frequencies. 
     
     
         9 . A sound reproduction system as set forth in  claim 5  wherein said system is or includes a portable playback device. 
     
     
         10 . A method for automatically adjusting the frequency response characteristics of a sound reproduction system, which system includes an input connected to an audio signal source and includes or is adapted for connection to an output transducer that delivers sound waves to a human listener, said method comprising, in combination, the steps of:
 applying test signals having different frequency components to said input to deliver test sounds of different frequencies from said output transducer to said listener,   accepting sensory data values from said listener indicative of the listener's perception of said test sounds of different frequency,   calculating gain control values from said sensory data values, and   automatically adjusting an equalizer connected between said input and said output transducer in accordance with said gain control values to compensate for at least some deviations of said data sensory values from specified data values.   
     
     
         11 . A method for adjusting the frequency response characteristics of a sound reproduction system as set forth in  claim 10  wherein:
 said step of applying test signals having different frequency components includes the substep of progressively increasing the volume of at least selected ones of said test signals and wherein   said step of accepting sensory data from said listener indicative of the listener's perception of said test sounds of different frequency includes the step, with respect to at least one of said selected test signals, of accepting an indication from said listener of the time when the level of said test signal increases to a specified level as perceived by said listener.   
     
     
         12 . A method for adjusting the frequency response characteristics of a sound reproduction system as set forth in  claim 10  wherein said test signals are selected from a group comprising test tones, noise signals, and speech signals of different frequencies. 
     
     
         13 . A method for adjusting the frequency response characteristics of a sound reproduction system as set forth in  claim 10  wherein at least some of said gain control values are related to the difference between the lowest sound level perceived by said listener at particular test signal frequencies and the lowest sound level which is perceptible by the average person at said test signal frequencies. 
     
     
         14 . An electronic sound reproduction system that includes apparatus for automatically adjusting the volume of different frequencies of sound based on listener specific data, said system comprising, in combination:
 an electronic amplifier connected to an audio signal source,   an output adapted for connection to an electro-acoustical transducer for delivering sound waves to a listener,   a test signal source coupled to said input for delivering audible test sounds to said listener via said transducer,   an input device for accepting one or more responses from said listener indicative of the listener's perception of said test sounds,   a processor for translating said one or more responses into measured audiological data characterizing said listener's hearing and for calculating control values from said measured audiological data, and   an equalizer for selectively amplifying the sound delivered to said listener at different frequencies in accordance with said calculated control values.   
     
     
         15 . An electronic sound reproduction system as set forth in  claim 14  wherein said processor is adapted for storing audiometric data indicative of the nominal frequency response characteristics of a person with normal hearing and wherein said processor is adapted for calculating said control values by comparing said measured audiological data with said audiometric data. 
     
     
         16 . An electronic sound reproduction system as set forth in  claim 14  which is adapted to preferentially amplify said audio signal to compensate for nonlinearities in the reproduction capabilities of said electronic sound reproduction system and differences between the listener's hearing response as indicated by said measured audiological data and a normal person's hearing response. 
     
     
         17 . An electronic sound reproduction system as set forth in  claim 14  wherein said electronic sound reproduction system is a portable stereo audio player equipped with stereo headphones and wherein said test signal source is adapted to apply separate test signals to each headphone earpiece to produce audiological data for each ear, and wherein said equalizer is adapted to preferentially amplify signals differently for each stereo channel. 
     
     
         18 . An electronic sound reproduction system as set forth in  claim 14  wherein said equalizer selectively amplifies sound at different frequencies so as to compensate for defects in said listener's hearing ability and for one or more of the following:
 defects in the reproduction capabilities of said audio signal source and of said electronic amplifier,   distortion introduced by said transducer, and   distortion introduced by room acoustics or any other sound transmission media which transmit said sound waves to at least one ear of said listener.   
     
     
         19 . Control software for adjusting a sound reproduction system so that said system selectively amplifies different frequencies to adapt to the hearing of a specific listener of said system, which software encodes instructions for said system to perform the operations of:
 generating test sounds of different frequencies and amplitudes,   accepting indications from said listener indicating how these test sounds are perceived by said listener,   automatically processing these indications to produce equalization control values, and selectively amplifying the sound delivered to said listener at different frequencies in accordance with said control values.   
     
     
         20 . Control software as set forth in  claim 19  which is adapted for use in a portable audio player with headphones.