Quote:
Originally Posted by Bruce Abbott
Another factor that 'scientific' tests often don't take into account is the response of the human ear, including psychoacoustic effects. For a fair comparison the signal should at least be 'A' weighted, so that components outside the normal hearing range are suppressed. Signals should also be evaluated at different levels corresponding to the dynamic range of music, rather than just at maximum volume where audio masking tends to suppress low level noise and distortion. |
Yes, the dB(A) curve or the later ITU-R 468 are quite common for psychoacoustic weighting of the SPL. In this case, it probably wouldn't do poor old Paula any good, I guess. There's little relevant energy around DC or near the end of the normal hearing range.
Your suggestion towards different levels (or amplitude) ranges as test source sure makes sense in cases of DACs with known nonlinearities. As it happens, I had such a test on my TODO already.
Another part to look at is the OpAmp. Typically, the TL084 was mounted in earlier Amiga models, replaced later by the LF347 with more reserves towards bandwidth at higher amplification. I wouldn't rule out the OpAmp as a source for overshoots, resulting in undesired harmonics.