Some thoughts on dust covers

As a record rotates, the air closest to the surface gets accelerated towards the periphery, drawing a steady stream of air down around the spindle. So reduction of air-born dust suggests closing the dust cover during play.

A dust cover also acts a bit like closing a window, and it will attenuate external airborne vibrations from reaching the cartridge.  My Garrard 301 table is in the same room as my speakers, which are either dipole Quad electrostatics or KEF Reference 1 with rear ports.  The dustcover is an acrylic affair made by SME and is voluminous with plenty of space.  I am very surprised that the sonic effect of closing my dustcover seems to be subtle to non-existent, at least to my ears.

Obviously, there is acoustic output from the needle / cantilever which is partly airborne and partly transmitted through the vinyl record, I am using a 5-mm Achromat to absorb record reflections and transmission to the platter, which leaves those airborne sounds we can just hear if we are close enough. They will reflect internally from a lowered dustcover but I would have thought the sound level would be far less than the speakers generate with the lid open!

So I put the lid down unless i forget!

So I have a question for those of us who advocate using a dust cover during play, for the primary reason to avoid the accumulation of dust. (The acoustic argument is different, I think.)  Let’s assume we all agree there is some sense to using a dust cover when the TT is not in use. Presumably, that keeps the area under the dust cover free of dust during those periods. Furthermore, when you remove an LP from its sleeve and place it on the now uncovered dust free platter, we can have reason to believe that the LP playing surface is also free of dust, relatively speaking. Then most of us use some sort of record brush prior to play, and some of us take steps to reduce the static charge on the playing surface, which would go further to delimit the possible accumulation of dust during play. Moreover, it takes about 20 minutes to play one side of a 33 rpm LP, so the net exposure time to the environmental dust is about that long. Do you in the dust cover user during play camp suppose that in the course of 20 minutes, the LP could possibly accumulate enough environmental dust to cause ticks and pops (presumably that could only affect the innermost grooves, since they would be exposed longest to the air before being "read" by the stylus) or to otherwise damage the LP? Even accounting for the fact that when you set the stylus down on the outermost grooves, the LP is likely to be "clean"? And finally, what do you think happens to dust in the air that you trap over the LP surface, by the very act of using the dust cover? At least with no dust cover, the airborne dust has a chance to pass harmlessly across the LP surface and land somewhere else. Once the dust cover is placed, the airborne dust has nowhere else to go but the LP surface.

@lewm

You raise good questions.  Hopefully, some grad student somewhere will research the answers.  I have my beliefs/worries, but it's all speculative.

I think for all those who think using a dustcover is a panacea, turn out the lights and cast a UV light on the playing surface and tell me it's dust free. [hint: it isn't]

A lot of high end tables (like mine) don't really even support using a dustcover, during play or otherwise. After hundreds/thousands of hours of use without one it's just not an issue.

LP12 owner here : Dust Cover always on even when DSD64 ripping Vinyl. Why ? Dust and Dog hairs coming from my Garage and my two Dogs. Plus I hear ZERO difference with the cover up or down !

For 40 years (ok...I took a 6 year hiatus) LP spinner (my previous MoFi hadn o dust cover ....period) and Dual CS515 prior always played with the cover down.

That’s my take on the subject.

Happy New Year Everyone !