Band-splitting time compensation signal processing device

1. A band-splitting time compensation signal processing device in an audio system for driving a plurality of speaker units, which have reproduction bands split, with a single amplifier for each channel via a crossover network circuit, the band-splitting time compensation signal processing device comprising:

a band-splitting circuit per channel for extracting a signal of a high-frequency band component or low-frequency band component from an input signal, obtaining a signal of the low-frequency band component or high-frequency band component by subtracting the extracted signal of the high-frequency band component or low-frequency band component from the input signal, and outputting the extracted signal and the obtained signal so that the high-frequency band component and the low-frequency band component are outputted as respective band-split signals;

a delay circuit per channel for delaying, for adjusting arrival time, at least one of the two band-split signals output from the band-splitting circuit; and

a mixing circuit per channel for combining the band-split signals after the at least one of the band-split signals is delayed by the delay circuit, and for outputting the combined signal to the amplifier,

wherein the band-splitting time compensation signal processing device carries out independent characteristic correction for each of the speaker units by adjusting the splitting frequency of the band-splitting circuit with that of the crossover network circuit, and adjusts and sets the time axes of the individual speaker units independently via the delay circuit inserted between the band-splitting circuit and the mixing circuit.

2. The band-splitting time compensation signal processing device according to claim 1 , wherein

the band-splitting circuit is constructed from an FIR filter having linear phase characteristics.

3. The band-splitting time compensation signal processing device according to claim 2 , wherein

the band-splitting circuit constructed from the FIR filter comprises:

a second delay circuit which is inserted into a path for obtaining the signal of the low-frequency band component or high-frequency band component by subtracting from the input signal the extracted signal of the high-frequency band component or low-frequency band component, said second delay circuit having a delay corresponding to a group-delay time of the band-splitting circuit.

4. The band-splitting time compensation signal processing device according to claim 1 , further comprising:

a phase adjusting circuit for adjusting phases of the high-frequency band component and low-frequency band component at a crossover frequency, the phase adjusting circuit being inserted into at least one of:

a path for transferring a band-split signal output by the delay circuit, and

a path for transferring a band-split signal output by the band-splitting circuit.

5. The band-splitting time compensation signal processing device according to claim 1 , further comprising:

a digital signal processing circuit for observing impulse responses of the plurality of speaker units which have reproduction bands split, for obtaining inverse transfer functions of the individual speaker units and performing a convolution algorithm, and for determining a delay of the delay circuit for adjusting the arrival time resulting from distance differences between the individual speaker units and a listening position.

6. The band-splitting time compensation signal processing device according to claim 1 , which improves linearity of transfer characteristics at a listening position by making an output signal equal to the input signal in terms of transfer functions.

7. The band-splitting time compensation signal processing device according to claim 6 , which employs a subtraction-type digital filter as the band-splitting circuit.