Dustcover Blues

AND your point is???

Mijo, I took a look at your system page.  You do have a beautiful and comfortable looking listening room, and you are obviously a highly skilled woodworker. It's always good when one hobby supports the other.  Seeing where your TT is located, on a shelf set into a wall with a shelf above, I do have to wonder whether moving your TT, just experimentally, would be worth a try. I get it that you don't want to radically reposition the TT to a permanent new location, but just for diagnostic purposes, it would be worth moving it temporarily, so that it is not against a wall and in a shelf.  In lieu of moving the TT, you could also remove the dust cover when playing LPs.

@rauliruegas , The subs I am using now do have paper cones. The ones I am thinking of using in the new subs have aluminum cones which I am not crazy about because they are easy to damage but I am space limited and I need a driver that will operate in a 1 cubic foot enclosure, These will. Subs you do not hear as much as feel even though I run mine up to 100 Hz. People shy away from running subs up high because everyone is used to using just low pass filters and not full two way crossovers. Plus, they have no ability to match them in time with the main speakers. They use very low low pass filters so they can not hear how bad the match up really is. If you try to cross this way at 100 Hz it becomes a real mess.

@lewm , thank you for the compliment Lew. Right now if I am going to listen to rock loud I keep the dust cover open. This weekend I am going to make a skirt to seal off the bottom of the turntable. Hopefully, it will work. Moving the turntable to the center or back of the room would certainly work as the bass is much lower in those locations. I doubt moving the turntable along the shelf it is on would do anything as the bass response is pretty much the same all along that shelf. As you may notice the turntable is right above the phonostage. There are holes drilled in the granite in strategic places to lead the wires through keeping AC wires away from signal wires. Moving the phonostage is not a nightmare but close. I can get to all the wiring by removing the records and equipment but it was originally put in place before the granite went down when it was much easier to deal with.

The turntable can handle the location fine except for this one fluke. The cabinet is not the problem. It vibrates very little if at all. The only direct connection between the cabinet and the wall is the trim around the upper cabinet and there are triple 2 X 6 studs under it. It is also not just planted on concrete. It is right on top of the foundation which goes down 12 feet to footing. 

If the skirt works I will make a new plinth cover and bring it down to within 1/8". Just enough room to be able to level the platter. If the skirt does not work then I will just have to keep the dust cover up when playing at volume which is not all that often, I'd wind up divorced. 

Rumble filter?

@rwwear , I already use one, a digital one! It is 3 dB down at 18 Hz and rolls off at 80 dB/oct. The way I run my subwoofers if I did not use this type of rumble filter the cones would wind up across the room with the first glitch:-) My problem is occuring just above the cutoff frequency. I could program the filter up higher but that would start interfering with the sound. The solution is in controling the resonance problem and there is a solution to this. I just have to figure it out.