Flat Response Amplifier?
If I understood well (speaking of audio frequencies from 20Hz to 20 KHz) , it is the electrical response of the amplifier over frequencies. This is actually a desired performance of an amplifier, normally plotted in bode : amplitude versus frequencies. and in that desire frequencies, you will see how flat it is, the flatness is measured in dB, if the variation over the range of frequencies is quiet big, you won’t be called the amplifier have a flat response.
This performance is measured first on the amplifier itself before measuring the system response (amplifier + speaker, it will be measure acoustically).
A system response (Amplifier and its intended speaker with baffle) normally performed in a controlled environment inside an anechoic chamber , it is a plot of the sound waves (not the electrical signal) – it is an acoustic test against the desired frequencies. The idea is to see how the amplifier and speaker works together.
Hmmm, you may have a good amplifier response, but when you drive the speaker (which is inductive load + resistive + capacitive), the overall response will change, in that case, speaker driver engineers needs to modify the speaker frequency response – sometimes called matching the speaker to the amplifier.
This is the same thing system engineers do in Phones with the desired frequency range of 300 ~ 4.2 KHz, well, up to 7.2KHz with the HD voice, amplifier were made to have a flat response electrically and adjust the speaker for the final acoustic response, in most case with digital processing to have the response tailored by DSP.
