Real-time audio spectrum analysis and dynamic volume control system based on FFT

Traditional sound mixers are often implemented using analog circuits, which have problems such as long response time and low adjustment accuracy. Therefore, this study designs a musical instrument tuning system based on Field Programmable Gate Array (FPGA). The system takes the Fast Fourier Transform (FFT) algorithm for real-time audio spectrum analysis and combines it with the Automatic Gain Control (AGC) algorithm to achieve dynamic volume control. Then, to improve the adaptive capability of the system, the minimum mean square algorithm is also introduced to optimize the AGC. Finally, FFT and AGC algorithms are integrated on the FPGA platform. The results showed that the amplitude range of the signal processed by the designed FPGA system was −1.0 dB-1.0 dB, and the gain effect of small speech signals was significant. The average objective difference grade score of the system was −0.67, and the average mean opinion score was 4.34. In addition, the power consumption, end-to-end delay, and frame processing time of the system were 132mW, 8.6 ms, and 0.2 ms, respectively. The experimental results demonstrate the real-time audio spectrum analysis and dynamic volume control performance of the proposed instrument tuner system, which can meet the high-quality audio requirements in multiple scenarios.