Acoustics, audio, and high fidelity
When you are stranded in a snow storm and you switch on cell phone to call for help, you won’t care what the phone set looks like, nor will you be too worried about the fidelity of audio coming through the earpiece (as long as you can understand what the other person is saying). Efficiency and reliability will be your major concerns. But when it comes to sound recording and reproduction, especially when the music is involved, quality comes to the fore. Minimizing distortion, for instance, becomes more important than the amplifier efficiency.