The Yamaha lacks sound quality and power. It has a tinny hollow sound. No bottom end either. Not sure the model of the Aiwa, but it’s much louder. Clean clear warm tones and as much bass as you want. I actually keep the bass settings on zero. The built in graphic equalizer helps tremendously with sound quality. What about what source you're comparing them with? Could be some difference there, too. The Yamaha unit is at the bottom level of their offerings fwiw....there's a reason it sells for $130. Could just be the Yamaha, personally I'd have looked at avrs rather than a 2ch receiver....