DIY Footers Part II

I posted a DIY footer forum here recently, I'll cut and paste it for reference:

"I can't help myself, I'm a tweak. I love playing with different footers and such, trying to find cost-effective solutions to vibration control. A lot of us use Tip-Toe style products but the trouble is they ruin hardwood floors and audio racks, damned pointy those cones. I've tried various "cups" under the points but find they make the sound a bit harsh, they're hard to get centered/seated properly under the cone, and they are a bit unstable. I tried some footers from a dealer, 1.5" by 1.5" squares built of ridged rubber, cork, ridged rubber. Stopped my turntable from skipping when walking around the room and saved my hardwood floors. Made the bass a bit flabby and the infamous PRAT went missing though.

I made my own "footers" this week, based on some inputs by a well respected stand manufacturer. This turned out to be a lot of fun and has solved my problem at a reasonable price.
Based on the recommendations of the stand manufacturer, the footers should be 3" by 3". They do not recommend you build a base the size of the item itself, but use individual footers. After some experimentation here's what sounded best:

You essentially make a sandwich, four layers to complete the footer. The top layer (and the one that comes in contact with the point of the cone is 1/2" MDF, next layer is a special compound that is used to dampen car doors and the like (Made in Germany, used by high end car audio installers), the next layer is 1/2" MDF, and the final layer (that comes into contact with your floor or rack) is thin cork. Reasonable cost but the damping material a bit pricey.

I used a 2' by 4' MDF top, 5 sheets of damping material, another 2' by 4' MDF, and finally 2' by 4' of cork. The best adhesive for this project is contact cement, it stinks to high heavens but works very well. You roll on a layer of contact cement to all the surfaces (except the top piece of MDF that comes into contact with the cone and the underside of the cork that comes into contact with the floor/stand). Let the surfaces dry til they're tacky then carefully make your "sandwich". You then lay some heavy well-distributed weights on the assembly and let it dry for 24 hours. You now have a pretty substantial 2' by 4' sandwhich ready to cut.

You need a table saw with a fine carbide tipped blade to get a good clean cut. A 2' by 4' sandwich yields about 100 these of 3" by 3" footers (there's always a bit of waste). I spilt the cost and the yield with a fellow 'phile, we're pretty happy with the results. If anyone is interested in learning more or seeing some pics of the final product drop me a note and I'll be happy to respond."

Well folks, we're back at it again, this time we intend to use 1/2" plywood rather than MDF this time around. The constrained layer approach works well and we intend on seeing if multiple layers (plywood) will make an audible difference. Oh, and for those who asked about the damping material we use; it's definately made in Germany, here's the info:

Wurth Noise Suppression Pads

Heavy bitumen pads with aluminum coating, self adhesive.

Suppresses transmission of noise caused by vibration, moving parts of the drive shaft, all parts under the car floor, wings, doors, and other panels.

- Strong adhesion
- Non pealing
- Suitable for painting
- Resistant to water, weak acids, alkalines, etc
- High temperature resistance

Sold six pads to a package, each pad is 550 x 250 x 2 mm

Wurth part no: 890 100 060

I'm curious what the plywood vs. MDF material change will make on the overall sound. Stay tuned folks! Jeff