Equalizer Circuit, High Fidelity Regenerative Amplifier Including Equalizer Circuit and Acoustic Characteristic Correction Circuit in High Fidelity Regenerative Amplifier

摘要

The present invention relates to an acousticcircuit for correcting a sound field characteristic. Afrequency characteristic of regenerated sound is made flatover as a wide frequency range as possible and a phasecharacteristic is adapted to match the characteristic of thesound field in which regenerated sound is obtained byeliminating phase distortion so that the regenerated soundis brought close to natural sound extremely.The present invention realizing suchcharacteristics includes an equalizer circuit having amedium frequency and high frequency correction circuitshaving a characteristic that a phase of an input auralsignal advances as a frequency of the aural signal isincreased in a higher frequency range than the vicinity of 1KHz and a circuit constant which advances a phase of thefrequency from about 1 KHz to 5 KHz relatively in order toattain far and near feeling, and a low frequency correctioncircuit having a characteristic that a phase of the inputaural signal is delayed as the frequency of the aural signalis lowered in a lower frequency range than about 1 KHz and acircuit constant having a reverse characteristic to a peakof a resonance frequency of the sound field to beregenerated, the medium, high and low frequency correctioncircuits being connected one another. Further, the presentinvention includes a high fidelity regenerative amplifierprovided with the equalizer circuit connected to a phasecorrection circuit for correcting a phase characteristic ofan amplifier circuit for amplifying regenerated sound withhigh fidelity over a wide frequency range and an acousticcharacteristic correction circuit in the high fidelityregenerative amplifier having an impedance conversioncircuit connected to the equalizer circuit to convert animpedance of the equalizer circuit to a proper value.