Hearing aid having plural microphones and a microphone switching system

A hearing aid apparatus comprising:

• an omnidirectional microphone for converting sound waves to electrical signals;
• a directional microphone of at least the first order for converting sound waves into electrical signals, said electrical signals of said directional microphone having low, mid, and high frequency components;
• an equalization amplifier accepting said electrical signals from said directional microphone for at least partially equalizing the amplitude of said low frequency electrical signal components of said electrical signal of said directional microphone with the amplitude of said mid and high .frequency electrical signal components of said electrical signals of said directional microphone, said equalization amplifier having an equalized electrical signal output;
• a hearing aid amplifier for amplifying electrical signals received at an input thereof;
• and
• switch means including automatic means for automatically switching between first and second switching states in response to sensed ambient noise levels, said switch means connecting said electrical signal from said omnidirectional microphone to said input of said hearing aid amplifier when said switch means is in said first switching state, said switch means connecting said equalized electrical signal from said equalization amplifier to said input of said hearing aid amplifier when said switching means is in said second switching state, said automatic means comprising:.
• noise sensing means for sensing ambient noise and generating an output signal indicative of the level of said ambient noise;
• and
• fader means responsive to said output signal of said noise sensing means for gradually decreasing the relative amplitude of said equalized signal supplied to said hearing aid amplifier from said equalizer while gradually increasing the relative amplitude of said electrical signal supplied to said hearing aid amplifier from said omnidirectional microphone as said switching means transitions from said first switching state toward said second switching state, and for gradually increasing the relative amplitude of said equalized signal supplied to said hearing aid amplifier from said equalizer while gradually decreasing the relative amplitude of said electrical signal supplied to said hearing aid amplifier from said omnidirectional microphone as said switching means transitions from said second switching state toward said first switching state, said switching means transitioning from said first switching state toward said second switching state as the level of said sensed ambient noise increases and transitioning from said second switching state toward said first switching state as said sensed ambient noise decreases.

A hearing aid apparatus comprising:

• an omnidirectional microphone for converting sound waves to electrical signals;
• a directional microphone of at least the first order for converting sound waves into electrical signals, said electrical signals of said directional microphone having low, mid, and high frequency components;
• an equalization amplifier accepting said electrical signals from said directional microphone for at least partially equalizing the amplitude of said low frequency electrical signal components of said electrical signal of said directional microphone with the amplitude of said mid and high frequency electrical signal components of said electrical signals of said directional microphone, said equalization amplifier having an equalized electrical signal output;
• a hearing aid amplifier for amplifying electrical signals received at an input thereof;
• a noise sensing circuit for sensing ambient noise and generating an output signal indicative of the level of said ambient noise;
• a fader circuit responsive to said output signal of said noise sensing circuit for gradually decreasing the relative amplitude of said equalized signal supplied to said hearing aid amplifier from said equalizer while gradually increasing the relative amplitude of said electrical signal supplied to said hearing aid amplifier from said omnidirectional microphone as the level of said ambient noise decreases, and for gradually increasing the relative amplitude of said equalized signal supplied to said hearing aid amplifier from said equalizer while gradually decreasing the relative amplitude of said electrical signal supplied to said hearing aid amplifier from said omnidirectional microphone as the level of said ambient noise increases.

A method of operating a hearing aid apparatus comprising the steps of:

• providing said hearing aid apparatus with an omnidirectional microphone for converting sound waves to an electrical signal;
• providing said hearing aid apparatus with a directional microphone of at least a first order for converting sound waves into an electrical signal, said electrical signal of said directional microphone having low, mid, and high frequency components;
• at least partially equalizing the amplitude of said low frequency electrical signal components of said electrical signal of said directional microphone with said mid and high frequency electrical signal components of said electrical signals of said directional microphone to generate an equalized electrical signal;
• sensing the ambient noise level;
• connecting said electrical signal of said omnidirectional microphone for supply to an input of a hearing aid amplifier;
• connecting said equalized electrical signal for supply to said input of said hearing aid amplifier;
• gradually decreasing the relative amplitude of said equalized signal supplied to said input of said hearing aid amplifier while gradually increasing the relative amplitude of said electrical signal supplied to said input of said hearing aid amplifier from said omnidirectional microphone as the level of said ambient noise decreases;
• gradually increasing the relative amplitude of said equalized signal supplied to said input of said hearing aid amplifier from said equalizer while gradually decreasing the relative amplitude of said electrical signal supplied to said input of said hearing aid amplifier from said omnidirectional microphone as the level of said ambient noise increases.