Line 6 Pod Go - Clean/Clear bass tone?

I've had the Pod Go for a couple years and have used it with my Fender P bass to run straight to our digital mixer and into my IEMs. It's been fine, but I can't seem to be able to mix a preset that doesn't sound like a muffled, muddy, lackluster tone. It's as if the only bass tones I can get are the equivalent of having several heavy quilts draped over a speaker cabinet.

What can I do to liven up the sound and clear it up by "removing those heavy quilts"? I've been looking into getting an external preamp to add to a signal chain, but trying to save money first if there's a way around it.