Compensated speaker-microphone

DETAILED DESCRIPTION An object of this invention is to provide an improved microphone having a high fidelity frequency response.
Another object of this invention is to provide an improved communications system using a speaker also as a microphone.
In the present invention a microphone is provided for receiving audio sound signals and developing high fidelity representative output signals in response thereto, which includes in combination: speaker means, having a base resonant frequency, for receiving input sounds at audio frequencies and developing output signals at corresponding audio frequencies in response thereto; suppression means coupled to said speaker means for reducing the magnitude of said output signals having frequencies substantially equal to said base resonant frequency relative to the magnitude of said output signals having frequencies substantially above and below said base resonant frequency; and high pass filter means coupled to said speaker means for reducing the magnitude of said output signals having frequencies below a predetermined frequency relative to the magnitude of said output signals above said predetermined frequency.
A desirable frequency response from a speaker used as a microphone is obtained by reducing the excessive speaker response to audio frequencies close to the base resonant frequency of the speaker by one apparatus, and also reducing the speaker response to all audio frequencies below a predetermined frequency by another separate apparatus.
In a communications system a receiver is connected to a speaker and when the receiver is rendered operative, by receiving a control signal, the audio frequency output of the receiver drives the speaker.
The speaker is also connected to a compensation network and a transmitter.
When the compensation network is rendered operative by receiving a control signal, the electrical output signals of the speaker are modified by that network to produce a high fidelity frequency response and the modified speaker output is then sent to the transmitter