Amp measurements/specs killed audio quality. Seriously. Along with the quest of small sized LOUD speakers.
A traditional amp (look at any standard 11th or 12th Physics text book), produces about 1 Watt to 3 Watt power, and a lot of measured distortion. They sound wonderful when created using discrete components (mostly tubes those days, and big transformers). You needed those big single driver speakers to make a reasonable amount of sound with the small watt amps. Anyway those speakers were mainstream,, and had close to 100dB/W efficiency.
Then came less efficient but small speakers which split sound between different drivers using networks, and hoped that your brain would cobble it back; despite the phase shifts.
Next step was the need for more powerful amplifiers, so the input signal (wave) was split into the lower and upper halves, and then amplified using separate amps (push-pull). Once again we just hoped that it would be all fine once your mind stitched it back.
From there it just went down hill. You could sell anything as long as it had a huge wattage and low measured distortion. Who cares about the subjective opinion about how it sounds. You could always argue the way you wanted, or whatever suited your balance-sheet. Someone figured out that the measured distortion (THD) would be close to 0.0x%, instead of x%, if you just took some of the output signal and put it back into the input (negative feedback). Guess what, everyone did it! And it can also improve performance (gain stability, linearity, frequency response, step response) and reduces sensitivity to parameter variations due to manufacturing or environment (great!). Does anyone who is still reading still remember that we started the discussion on producing music?
Sorry to deliver the
red pill
regards,
Sharad Medhavi