DCAudioDIY.com

Nice Rack? Holy crap! Man that is nice. Thanks for making me rethink what a nice rack looks like (and going back to the drawing board for mine). Also, thanks for re-defining the term 'nice'

I've been there a few times. It's truly amazing. You should hear the system that sits on it these days

Roscoe

_________________
I can explain it to you, but I can’t understand it for you.

A question was raised would 3/4 rod be able to support a heavy stereo. To that I would say likely yes. attached are two pictures of what I did with 3/4 rod and some 2 x 10 boards. Each shelf is independent so you can say, (approx) 10 feet of records / 4 nuts is the load each nut is carrying.

This is a pretty easy straight forward project but if you have questions let me know. I attempted to add a powerpoint slide show to this post of how I built this record shelf but the pptx extension is not allowed, and the file is 3.7 MB

- John

Break Break - OK 2 corrections, I used 2 x 12 boards (10 feet long) and I do have the center support boards so the weight on each nut is not
10 feet of records divided by 4. It is more like
Approximately 5 feet of records kind of divided by 4.

Mine is 1" threaded rods. 3/4 might be fine for a shorter rack,but would be too thin for a six foot rack. The issue is wobble unless the rack is triangulated. The area clamped by the nuts determines how stable it is. I would not use smaller than 1" hardware.

Probably adding angle braces is a good idea.

Jim, I assembled it myself. Laid the thing horizontally. Lifting it took Renie's help. I'd be concerned about it anywhere but on a concrete floor!

I see what you mean. I haven't tried any of this yet, so my comments are theoretical and have no experiments supporting them. The common 1" washer (2.5" D) provide 50% more ares than the common 3/4" washer (2" D). The wobble argument is exacerbated by the use of rubber washers between the steel washers and the shelves because the rubber allows some flexing when it is compressed. Plus the metal washers would compress the shelf material, leading to some wobble.

Stuart, is the point of this exercise to make a rigid shelf with all elements connected to each other for vibration transmission, or are we trying to isolate each shelf from the others and the floor? Isolation may be improved if we use rubber bushings between the threaded rods and the shelf. Have you heard anything about this or will we have to experiment?

_________________
- Guy

You may want to make the rack rigid and try local isolation. Even if you were to isolate each shelf with rubber washers, the large area of a shelf makes it susceptable to airborne vibrations. If you have a particularly susceptable item like a turntable you may wish to make a heavy base and place it on the shelf with Sorbothane underneath. Sorbothane is probably the best rubber like material to absorb vibrations. Unlike many rubbers, it is very lossy and converts most of the vibrations into heat instead of transmitting them. Here is an interesting link:

http://www.sorbothane.com/

For may turtable I built a box out of MDFD and then filled it with sand. I then placed it on four Sorbothane feet that I had but could just as easily have used squares cut out of sheets. To get a thicker pad you can just use more squares stacked on top of each other. You can get them online from many places. Like any rubber material you should use something to keep it off finished wood to prevent staining. Here is a link:

http://www.sorbothane.com/

You can get this material on line. Here is a link:

http://www.ebay.com/itm/Sorbothane-Vibr ... 2a33c028c6

It comes in many thicknesses and durometers. The lower the durometer the "softer" or more compliant it is. Although you cannot completely eliminate transmission, the resulting frequency of the vibration is subject to a mass-compliance ratio. The greater the mass and the greater the compliance, the lower the frequency. With a turntable it is not difficult to get the resulting vibration below the resonant frequency of the arm/cartridge combination. Once below resonance, the amplitude of the vibration picked up by the cartridge is greatly reduced similarly to the drop off in bass response below resonance. I'm including a photo of my setup. With this setup I can jump up and down on the floor and the turntable will not skip.

Stuart, is the point of this exercise to make a rigid shelf with all elements connected to each other for vibration transmission, or are we trying to isolate each shelf from the others and the floor? Isolation may be improved if we use rubber bushings between the threaded rods and the shelf. Have you heard anything about this or will we have to experiment? [/quote]

The point was good sound. I heard about mechanical diodes, transmitting vibrational energy from the rack to the rods, then on to the floor, but not in reverse. I followed the advice of some other guys in the club. Whether or not it works well is very difficult to say. Transitioning my gear years ago when I first assembled it was a definite and not subtle improvement. Would it be still better with other alterations? Could be.......experimentation!

My lifespan and time is too limited to explore all possible/reasonable options; therefore, I have to take the advice/experience of others who have assembled systems which sound (IMHO) better than mine, in order to limit the work I have to do and money I have to spend.

What I have now is probably it for me, with the addition of nicer shelving and that rust preventative that Tomp suggested. THANK YOU TOMP!

Stuart

Stuart,

Here's a picture of my rack with the rest of the maple. I decided on fixed height shelves and solid leg attachment, 3-1/2" square legs. Large footers on the bottom, and local isolation of the components.

Jim

Beautiful! I bet that sounds as amazing as it looks! You are a pro!

Stuart