Statistical Signal Processing Research Laboratory

Multi-Channel Dynamic-Range Compression (DRC) enhances the audio quality by controlling sound loudness staying at comfortable levels.

However, the use of more channels increases computational complexity of the multi-channel compression algorithm limiting itself to advanced but costly hardware such as hearing aid device. We proposed two different digital nine-channel DRCs with optimized structure capable of running on smartphones and other affordable portable digital platforms in real time.

1. FIR Filter Bank DRC (with speech envelope compressor)

2. IIR Filter Bank DRC (with proposed compressor)

Fig.1. System Diagram of both proposed FIR filter bank DRC and IIR filter bank DRC.
Fig.2a. Frequency Response of proposed FIR filter bank. 
Fig.2b. Frequency Response of proposed IIR filter bank.
Fig.3a. System Diagram of speech envelope compressor.
Fig.3b. System Diagram of proposed compressor.
Fig.4a. System Diagram of real-time implementation of proposed FIR filter bank DRC.
Fig.4b. System Diagram of real-time implementation of proposed IIR filter bank DRC.
Fig.5. Calculation Complexity of both proposed FIR filter bank DRC and IIR filter bank DRC.
Fig.6. Objective results of both proposed FIR filter bank DRC and IIR filter bank DRC.
Fig.7. Subjective results of both proposed FIR filter bank DRC and IIR filter bank DRC.

-5 dB

  0 dB

+5 dB

+10 dB