Quote Originally Posted by jimlucci View Post
Well, I don't know whether to laugh or cry. Just on a hunch, I took an older laptop that had less manufacturer device add-on's (ie. Realtech) and had both 2.0 and 3.0 usb ports, attached my Modi 3+ Dac and Umik1, set it up in my main listening position and ran a quick sweep from 10Hz - 20kHz - FLAT RESPONSE CURVE END TO END!!!! I am not sure where the problem lies with respect to my original laptop, but this laptop yields frequency response data more like what I was expecting. I am still playing around with the Umik1 connections to usb 2.0 and usb 3.0 on this laptop (they seem to behave slightly different, but I am not sure just yet). Once I am convinced that I have the setup on this new laptop correct, I will be running some controlled sweeps of my tower/sub setup and re-post them here. I think the insidious thing about this whole exercise is that the Umik1 partially worked. Had it not worked at all, I could have spent my time fixing a real problem instead of chasing my tail for 2 weeks.
Very happy you resolved the issue! Yes, please post the measurements now, I always enjoy looking at these.

Your issue is one of the reason I generally don't trust measurements taken using laptops / PC's etc. I have a very old and basic laptop (Windows XP) that is fully dedicated to trying out software like REW.