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Below: Pre-visualizing the wall mounted rack for my Teres. I had decided that I needed to wall mount my Teres in my upstairs flat. Problem is, nobody sells a TT wall rack robust enough. Might as well build one, I thought.
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Material is to be mild steel in 3 shapes. 1 inch square (.07 wall) seamless tubing, and 1/8 inch thick plate (2 different widths). The various pieces are to be welded together using a Victor oxy-acetylene set. The completed rack is to be bolted to the studs behind the sheetrock with six 5/16 x 3 inch lag bolts. (lag bolt = A kind of hex head bolt designed to screw securely into wood) The main goal is to maximize rigidity of the TT mount while isolating from floor vibrations. (very springy 3rd story floor) The four ball studs are designed to support a rigid granite plate shelf which in turn supports the turntable itself. The ball studs thread into coupling nuts where are welded to the interior of the square tubing.
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above: A 3D render pre-visualizing the finished assembly. That's a Teres model 135 less tonearm on top of the platform.
Notes: 3D geometry creation in Rhino 2.0, rendering in Povray V3.1 using Moray V3.2 as an interface.
OK so much for "virtual reality".
Below is the reality.
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There you are. This makes a sturdy enough brace for an adult to do gymnastics on. The actual fabrication process went ahead as planned. To mitigate the frames tendency toward ringing, the internal volumes of the tubes were filled with polyurethane expanding foam. Access holes for squirting in the foam had been drilled into the tubes prior to the weld process.
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Trying a Neuance isolation platform on top of the frame. I had just received a Neuance shelf from Ken Lyons' company "Greater Ranges". Ken produces these excellent constrained layer isolation shelves and sells them direct. Price is affordable.
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Trying the frame with a 3 x 18 x 18 inch granite plate that I sourced from Grizzly industrial. (online catalog at http://www.grizzly.com/ (search the site using keywords "granite plate")) Note that the 4 adjustable supports are not being used. Instead I have substituted three acorn nuts and three 1/2 inch thick lead plate pads to interface the granite to the frame.
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Above photo. The Teres sitting directly over the Granite. Sound is good but not as good as below.
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Above photos: placing the Neuance shelf directly over the granite plate and the Teres atop the Neuance. Good sound this way...!
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Above photo #10: current config (2/5/05)
Summary Comments:
This wall rack gave a significant sound improvement compared to the previous shelf that I had made from Home Depot triangular brackets and a sheet of plywood. Funny how a more solid foundation beneath the TT also gives a more solid foundation beneath the music it makes. A more coherent, detailed, rhythmic and dynamic presentation was the initial result I heard. But then I began experimenting with two different shelves, pads of 1/2 inch thick lead, brass acorn nuts, etc. Results went like this:
config 1) Neuance shelf directly over the four adjustable supports. (photo 5) The threaded studs with the brass acorn nuts made good supports for this shelf by allowing the shelf to be made exactly level and also to adjust tension just right so that each 'foot' made solid equal contact with the shelf. Background isolation was excellent this way. There was a natural airy sound that, unfortunately, lacked low frequency slam.
config 2) Granite plate (3 x 18 x 18) over lead pads and large acorn nuts as cones. (photos 6 & 7) Big improvement in low frequency slam. Overall sound was quite good, I thought. Maybe there was a bit less background silence compared to the first configuration but the bottom end foundation was more important.
config 3) Neuance shelf directly over the granite plate. (photos 8,9&10) Better still. Background silence gets blacker and quieter but at no apparent cost to low frequency slam. Midrange and high frequencies opened up into a more natural and airy presentation. Subtle details gained improved definition.
Note 1) In view of the above comments I have to admit that the wall mounting represents a compromise made to compensate for flimsy architecture of the building I'm in. These days it seems as though floors are like springs. Given a more solid floor, I would have preferred a rigid floor mounting. As it is, I can jump up and down next to this turntable without causing nary a quiver.
Note 2) The more solid the foundation beneath the Teres, the more powerful the low frequency slam and kick. This became clear when first trying the granite base on this rack. Big difference..!
Note 3) photo #10 shows a different platter mounted to the Teres than in the other photos. The lead-shot chambered platter was an upgrade offered by "Teres Audio" through an exchange program.
