Which "tool" for signal control gives ' The most rewards ' ?

https://www.youtube.com/watch?v=82pYzfP7PlcEqualizer

Digital signal processor

Digital signal processing dramatically improves the sensitivity of a receiving unit. The effect is most noticeable when noise competes with a desired signal. You can perform different tuning tasks with a DSP such as controlling time alignment to create an excellent center image, you can tune crossovers to send only certain frequencies to tweeters, mid range speakers, mid bass speakers and subwoofers, and you can control an equalizer to tune each speaker to a target level response !