I've been having the same problem. Helix + Powercab just seems muddy, bassy, thin and not quite right - no crispness or sharpness since recent update. I thought it was just my ears, the guitar I was using, old age ...but it has persisted. So i thought I would check out any forum comments and I see I'm not alone. I will check out the global settings and re install etc. but this has never happened at any previous update.