Did you have both fractal and the Focusrite connected via usb? I had an odd issue my second day with my FM3 (which I love) and even though I had the proper ins and out selected in my computer settings/interface I was getting the same “muffled sound” due to phase cancellation with double input signals. I restarted my computer and it was all fine again. The JBLs although not amazing (I have them as well) still sound quite nice for the money.