I had a Holley blue and it was annoyingly loud. took it apart to see if something was wrong and it looks perfect. put on my Dad's old Edelbrock 120 gal and it was half as loud. The Eddy pump is self regulated but is adjustable. It showed just over 5.5 psi on my gauge at the carb, turned up the pressure at the pump and it got a fair bit louder once almost 7 psi was reached. Still quieter than the Holley though.
I run around with the pump set at just under 6 psi and crank it up to 7 for racing, probably does nothing for me but I do it anyway.

Don.