Multiband DRC system and method for controlling the same
A multiband DRC system and a method for controlling the same are disclosed. In accordance with the present invention, the system and the method are capable of increasing an overall loudness of an output signal by controlling thresholds and gains of plurality of DRCs included in the multiband DRC system according to frequency bands.
1. A multiband Dynamic Range Compressor (DRC) system, comprising:
a filtering unit for dividing a digital audio signal into a first band audio signal through an N th band audio signal according to (N−1) crossover frequencies;
a first DRC through an N th DRC having a first threshold through an N th threshold, respectively, the first DRC through the N th DRC dynamically compressing the first band audio signal through the N th band audio signal, respectively; and
an adder for adding output signals of the first DRC through the N th DRC,
wherein the first threshold through the N th threshold are selected according to a target Total Harmonic Distortion (THD) and the (N−1) crossover frequencies, wherein the first threshold through the N th threshold are values of output power.
2. The system in accordance with claim 1 , further comprising a post DRC for dynamically compressing an output signal of the adder.
3. The system in accordance with claim 2 , wherein the filtering unit includes a first filter through an N th filter for dividing the digital audio signal into the first band audio signal through the N th band audio signal, respectively, according to the (N−1) crossover frequencies.
4. The system in accordance with claim 1 , further comprising a gain controller for controlling gains of the first DRC through the N th DRC according to an upper limit of differences between the gains.
5. The system in accordance with claim 4 , wherein the gain controller limits one of gains of an L th DRC and an M th DRC such that a difference between the pains of the L th DRC and the M th DRC is no more than the upper limit when the difference between the gains of the L th DRC and the M th DRC exceeds the upper limit, wherein each of L and M is a natural number satisfying 1≦L, M≦N.
6. A method for controlling a multiband Dynamic Range Compressor (DRC) system, comprising:
(a) dividing a digital audio signal into a first band audio signal through an N th band audio signal according to (N−1) crossover frequencies;
(b) selecting a first threshold through an N th threshold of a first DRC through an N th DRC, respectively, according to a target Total Harmonic Distortion (THD) and the (N−1) crossover frequencies, wherein the first threshold through the N th threshold are values of output power;
(c) dynamically compressing the first band audio signal through the N th band audio input to the first DRC through the N th DRC according to the first threshold through the N th threshold, respectively; and
(d) adding the first band audio signal through the N th band audio signal dynamically compressed in step (c).
7. The method in accordance with claim 6 , further comprising (e) dynamically compressing the first band audio signal through the N th band audio signal added in step (d).
8. The method in accordance with claim 6 , wherein step (c) comprises:
(c-1) inputting the first band audio signal through the N th band audio signal to the first DRC through the N th DRC, respectively;
(c-2) selecting gains of the first DRC through the N th DRC according to an upper limit of differences between the gains; and
(c-3) dynamically compressing the first band audio signal through the N th band audio signal according to the gains selected step (c-2).
9. The method in accordance with claim 8 , wherein the step step (c-2) comprises limiting one of gains of an L th DRC and an M th DRC such that a difference between the gains of the L th DRC and the M th DRC is no more than the upper limit when the difference between the gains of the L th DRC and the M th DRC exceeds the upper limit, wherein each of L and M is a natural number satisfying 1≦L, M≦N.