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Bronze Member Username: Wasserman12Post Number: 26 Registered: Jul-06 | I have my table on a wood entertainment shelving unit that I built. Its pretty stiff- fairly well built, and it supports my linn axis, my luxman receiver, a dvd player, a tape deck two speakers and a television. I imagine this is causing more serious listeners to roll their eyes. I have recently noticed that when I walk across the floor near to the turntable, the sound occasionally acquires a mild vibrato. Any suggestions short of abanding the shelving unit? I had thought of making some kind of suspension out of foam rubber and mdf, but it seems like people around here favor heavy, solid isolation, like granite or something. |
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Gold Member Username: Stu_pittIrvington, New York USA Post Number: 1535 Registered: May-05 | One of these days I'm going to play around with isolation for my turntable. I haven't done it yet, so I'm not claiming to be anything close to an expert. I also have my turntable on top of a handmade wooden cabinet. I believe that different types of turntables respond to different types of isolation. From everything I've heard about Linn, they are VERY touchy in setup and isolation. Most of my Linn knowledge is about the LP12 though. I'm assuming that all of their tables have the same design framework in mind. A lot of Linn owners (and other turntable owners) prefer wall shelves to just about anything else. Theoreticaly, they aren't prone or as prone to vibrations from the floor. Some wall shelves have isolation in the base as well. It's hard to explain this one for me, but in link I'm providing should explain it all. That one's pretty expensive though. If you go the wall shelf route, you can still keep everything else in the rack. There are a lot of other ways as well. Hockey pucks, squash balls, tennis balls cut in half, and wood blocks (I've heard the Jenga game blocks work pretty well) are pretty cheap and could be worth the few bucks they cost to experiment with. Then there are isolation cones, spikes, and some gel type products that can cost a bit more. Or you can go the slab of granite, marble, butcher block, or acrylic route. To further complicate the issue, you could put stuff like squash balls, cones, etc. under the slab of granite, marble, etc. I've heard that acrylic (or was it PVC?) is very inert and a great isolator. Who knows? Or you could go with the sandbox route. It seems like it would work pretty well, but you need to invest time and some money in it that isn't recoverable if it doesn't work out right. I've wanted to try it, but with my luck it would be wrong for my set up and make it sound worse. http://www.cognitivevent.com/sandbox.html This store has a lot of good stuff. Prices vary, but they're in line with every other source I've come across. http://www.musicdirect.com/Default.asp A wall shelf that keeps coming up - http://www.musicdirect.com/products/detail.asp?sku=ATARVW1PRO The absurdly expensive wall shelf that isolates in a few different ways - http://www.musicdirect.com/products/detail.asp?sku=APAGODEWALLMAPLE I guess what I'm trying to say is be creative. When I've got the time, I will too. |
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Gold Member Username: Jan_b_vigneDallas, TX Post Number: 9374 Registered: May-04 | . The basic problem with isolating/decoupling a turntable is you need to firmly couple the table to something for it to work properly. The two objectives are at odds with each other. Mass works well to isolate a table if the mass is inert. Unfortunately, you've shown that your support isn't immune to feedback. When mass is excited by feedback or external motion, it tends to hold onto that movement/resonance longer than a light support system would. Therefore, many tables, the Linn LP-12 especially, prefer a very light and rigid support system that releases resonance quickly. And, of course, light and rigid are at odds with each other. Until you spend lots of money, at least. The vibrato probably comes from the floor boards and not exactly the table. You first need to address the requirement of a solid support system. Wall mounts work well if your floors are floppy. As is, your entire shelving system is set in motion by the movement of the flooring and this causes the stylus to wander in the groove and the platter to move in relation to the motor. Placing more mass on top of this support system will only exacerbate the problem by making the system top heavy and even more unstable. Different supports will give various characteristics to the music and you can, if you want to experiment, try several types of supports to find which suits your tastes. I would really suggest, however, you contact a Linn dealer and ask for their advice. They will prefer something expensive, Linn dealers always do, but you can take their suggestions and go from there on your own budget. Put "audio isolation devices" into a search engine and do some refining to get the answers you need to develop some ideas regarding what is possible. My ISP just did an upgrade which wiped my bookmarks - thank you very much! - or I would lead you to some sources. In general, I would say "think rigid" and wood seldom qualifies. . |