Fractal Audio Systems
Depends on the amp. Mesas have a lot of negative feedback so the speaker impedance has less influence on the response. Repeat that test with an AC-30 and see what you get .Yeah I did some tests with a miked cab vs Two Notes and an IR shot of that mic up. I essentially got a straight line but the low end had a scoop on it. Nothing too big though.. it was like 1dB or so but still, not flat.