I just switched audio interfaces, from a Native Instruments Traktor Audio 2 to a Novation Audiohub. FIgured I could simply my rig by combining the USB hub and audio interface into one unit, plus have a little more flexibility. But I can't seem to get it to work. Set the sample rate at 44.1, all buffers on "auto" but the sound that comes out is horribly distorted. Kinda like the chainsaw in that old Jackal song! My efforts thus far have involved running Kontakt within Forte, and I just can't get anything but noise out of it.
However, if I just run Kontakt directly, into the same rig, the sound is fantastic! Same sample rate, etc. It is only when I am using Forte as the host that I have these issues.
I am able to switch back to my Traktor Audio 2 interface, and everything is cool again.
I'm currently using the same audio interface (i.e. Novation Audiohub 2x4) with my ASUS ROG G751JL laptop (running Windows 10 64-bit Home) and encountered the same distortion problems when using Forte 4 with my virtual instruments (Pianoteq 5.xx, EWQL-SO, Lounge Lizard EP4 etc.)
Try opening the Audiohub UAC2 Panel from the programs listing menu of windows (or from the live tiles of Windows 8.1). By default, the "Balanced" option is selected. Make sure that you select the "Recording" option. That solved the problem for me - for the most part. However, once in a while I'd get that occassional distortion issue after using the interface with Forte for some number of hours (around 3 or 4 hours of continued use) - usually happens when I'm doing a lot of patch changing from Pianoteq 5 and EWQL-SO under Forte 4.
There seem to be some "issue" reported by some users with Audiohub 2x4 when used under Windows 10 and Novation's support response was more on the time it takes the interface to get "enumerated" once connected to a PC's USB port running on Windows. I haven't checked lately if there is any updated Windows-driver for Audiohub 2x4.
Anyway, hope this helps.