I have measured the frequency response of my MKIIa and see some rolloff at both ends of the spectrum. It's not too bad when playing a WAV off the EMPEG, but is a bit more significant when playing a test source through the EMPEG (via the aux-ins).

The attachments to this message (and the next two replies) show the frequency response I measured on my primary MKIIa a few weeks ago when I was setting up my PC based RTA. These graphs already have a compensation curve factored in that compensates for my sound card's response anomalies.

The RTA resolution is set at 1/12 oct in all these images.... Curve smoothing is not enabled, which is why you see steps in the response curve on 1/12 octave boundries.

The image attached to this message shows the frequency response measured at the EMPEG's 1V outputs while playing a pink noise WAV ripped directly from directly the 2001 IASCA test disc.

The response is pretty good, but other audio equipment I have tested is generally flatter.

I tried various output levels (-10 dB to 0 dB), the 1V outputs, the 4V outputs... all yielded pretty much the same results.

Looping my sound card output back into it's line input results in a nearly ruler flat measured response with the same compensation curve (see second reply to this message). Playing this pink noise track on a good home audio CD player also yields a flat response curve. Therefore, I am confident in my test setup, and that these graphs shows the actual response of my EMPEG.