Questions on How To Stands/Racks

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moray james

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Questions on How To Stands/Racks
« on: 17 Jan 2003, 07:36 pm »
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I just thought I would pass along a couple of interesting “points” of information to the guys out there who can’t afford to buy every new toy that they might like to have.
   I read that a number of you are looking at building racks or stands of your own to save a buck. You want to remember that you are dealing with an audio system here and even your SS components are very microphonic in nature. Energy in the form of vibration will travel along surfaces of material, the harder the faster. This means that metal bar or pipe is a very fast conduit and offers no ability to damp the energy or add loss. Plastic plumming pipe is better than steel as it is both stiff and lossy. Noel Nolan at Skylan Stands has a special plastic alloy custom made for his product which allows for even greater loss factor. You want to have a combination of stiffness and loss. If you had to error on the side of one or the other more loss is better than more stiffness. It is for this balanced reason you also don’t want to throw tons of mass at the situation. Reason being that sooner or later that mass will resonate and when it does somebody has to stop it!  So yes lead or steel shot in a stand will add more mass but it provides zero loss. Sand is your best option as you get mass and lots of loss in the form of friction as the particles vibrate. Just pack the sand extremely well and the mass will be high. For a given volume lead shot would of course give more mass but as I said no (zero) loss as there would be no vibration friction.  You can gain back any difference in mass another way. On a speaker stand instead of using 4 spikes use 3 spikes. You have now increased your mass loading by 25% for free. Further you all know that it is impossible to balance 4 spikes, you can get close but they will always rock. With 3 spikes you have a tripod which is stable on any surface. Now set up is a breeze, want to adjust your front to back tilt? You simply adjust ONE spike! Want to adjust your left to right tilt? You simply adjust ONE spike!
   The above mentioned tripod idea is also crucial for the same reasons of balance and mass loading when it comes to mounting loudspeakers on a stand. Three point mounting with hard purpose designed mounting feet will make all the difference. I will tell you also that you want two feet at the front two corners and one foot at the middle of the rear of the speaker. Just give it a listen the wrong way around (ala totem) and you will hear a huge difference. So why do they do it the “wrong” way? Well the marketing guys know that there are some people with such thick speaker cable that it would probably topple the speaker at the back side if there were not two spikes.
   For spikes you want to use the hardest material possible. “Ramset” spikes are special case hardened steel spikes used to fire through steel construction beams. Don’t use cold rolled or hot rolled steel and please don’t use brass. The softer the material the more smear and blur you will get.
   Remember too that in sheet goods MDF is a good compromise material for shelves and case goods. Just be aware that almost all the strength and stiffness in such materials lies in the surface skin of the material. If you were to say spin some groves in the surface of MDF to say locate some tube for vertical uprights in a rack design you would be loosing almost all of the materials stiffness. The rack would still hold up your gear but it wouldn’t sound as good as it could if the grooves were not there.
   Do you begin to see a trend here? Stiffness and loss, you need to know when and where to use them and you need to understand how best to balance them. Louis has a fine understanding of these topics and that is why he can build such a fine speaker cabinet. There is no magic unless it is that of appreciating and understanding balance. Noel Nolan’s “Iso Platforms” and stands show the same degree of design excellence and there in lies the synergy in these products.  Both companies provide products which excel in design quality and express decades of audio experience.  Like magic, in manufacturing there is often much that the eye does not see, experience makes all the difference.
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