| 摘要 |
An audio apparatus includes a signal generating circuit for generating a first electrical audio frequency signal corresponding to audio information received from a source, such as a phonograph turntable, tape recorder or FM/AM tuner. A loudspeaker generates an acoustic signal in response to the first audio frequency signal, and a microphone pick-up receives the acoustic signal for generating a corresponding second electrical audio frequency signal. A filter network then separates the first and second audio frequency signals into respective low, mid and high-frequency ranges, and three comparator circuits compare the first and second audio frequency signals in each frequency range and produce a respective error signal in each frequency range. A tone control or equalizing circuit then adjusts the levels of the several frequency ranges of the first audio frequency signal in response to the respective error signals, whereby to ensure accurate acoustic signal generation by the loudspeaker corresponding to the first audio frequency signal, regardless of room and loudspeaker design.
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