dustcover up, down or off


To get the best sound from a TT, should the dustcover be up, down or removed all together? I have always removed my dustcover, but I recently read an opinion that having it in place prevents unwanted vibrations from the speakers from reaching the TT. What are your thoughts? Thanks.
tbromgard
"Seriously, I've seen tt covers that surround and enclose the entire table without being attached. I really like that idea!"
Actually Mapman, that is a good solution, but they tend to be heavy if properly constructed, making them a PITA to use; and really not any better than a hinged cover if the TT is, or can be, fitted with one (not always the case these days ;-) In addition, they need to be fitted with some kind of resilient material around their bottom edges so they don't potentially rattle against the shelf ;-) The bottom edges of even hinged dustcovers should land on something resilient and not right on the plinth.
I have a Music Hall 7, and it definetly sounds better with the dustcover removed.
I used to own a Music Hall mmf 5.1, and noticed within the first month of ownership noticed that it sounded much better with the dust cover removed. What everyone else is saying here is correct: it acts like a microphone and causes the plinth and other components to resonate.
I bought an MM7 (used with no cover) and replaced the cover with a new MM7 cover. When the cover is down the counter weight starts to hit the cover during the last 1-2 minutes on the last track of each LP, so I leave it open. Stevecham: does this happen to you?