In the course of testing the Black Lion AM/CHA1 dual-channel equaliser (/sos/dec10/articles/black-lion-amcha1.htm), reviewer Hugh Robjohns took a number of technical measurements using an Audio Precision Analyzer, and we thought it would be useful to make these available online. Click on the images to the right if you wish to enlarge them.
The range of low-band response curves at high and low Q settings.
With the low-band set to shelf mode, with high and low Q settings (the latter providing less overall gain)
The low-mid band EQ responses span the critical midrange region.
The upper-mid band response plots revealing the peculiarly 'bent' high-Q cut response (see main article).
A set of responses for the high-band in peak mode with high and low Q settings.
The high-band responses in shelf mode.
A distortion product plot illustrating the dominant third-harmonic distortion character which emanates mostly from the transformers.