Are Dust Covers a MUST

A cover can block vibration because it acts like a fence (think Faraday cage but for airborne radiation instead of electromagnetic) between the excitement in the surrounding air and the tonearm. Consider, can the neighbors hear your rig better with the window open or closed? The chassis itself is necessarily exposed to the environment and hence the damped plinth. To stretch the idea even further the cover typically damped by felt pads above the chassis may act to soften chassis induced vibration similar in effect to the mass loading of component cases.

Faraday cage?1?! Not even close to a good analogy. Listen to Vu, he knows what he's talking about.

Concur with Vtvu. Having a dust cover is probably going to make the system sound worse. ime, I tried using Cardas RCA covers and they noticeably imparted a metallic signature to cymbals that was not there when they were removed. The only issue was that they decreased the noise floor significantly so I went looking for replacements. I've recently picked up the Acoustic Revive units which I hope won't have the same drawbacks but will have the noise floor benefits.

Yeah Dan but it was a toss up between that and the Cone of Silence in the chief of Control's office from Get Smart.

LOL!!