Apparatus and methods for auditory conditioning

Apparatus for enhancing an input signal representation of sound, comprising:

• input means for providing a signal in the audio frequency range in response to said input signal, said input means comprising:
• an amplifier stage having a gain inversely related to the amplitude of said input signal, whereby said amplifier stage provides a compressed gain signal, said amplifier stage comprising:
• a summing amplifier of the type that provides an output signal having an amplitude proportional to the sum of the amplitude of signals respectively applied to its inputs, said input signal being applied to a first input of said summing amplifier;
• and
• an automatic level control circuit connected to the output of said summing amplifier and to a second input of said summing amplifier said automatic level control circuit having a gain inversely related to the signal provided by said summing amplifier;
• an audio filter, connected to said input means, that provides a filtered audio signal, said audio filter having variable transmission characteristics;
• output means, connected to said audio filter means, for providing an output signal in response to said filtered audio signal;
• and
• control logic means for selecting said transmission characteristics and for causing an attenuation and equalization of said output signal in accordance with a stored program, said control logic means being operable to alternatively cause a coupling of at least one of said input signal and said compressed gain signal to said audio filter.