Controlling Volume of Fretless Slides?

[LeonD]

I've recently started playing a fretless, five string Zon Special. Per my sound man, I've dialed in a great tone and it cuts thru the band nicely.

My problem is that my slides are noticeably louder than my normally played notes. I'm being told that the slides are so much louder that it's distracting.

So I'm looking for a solution. Is this a technique issue? Or is it a setup issue? FWIW, the mwah this bass has is huge; it borders on uncontrollable at times.

I appreciate any suggestions,
LeonD