Mapleshade boards under speakers

Jrb25,

According to Mapleshade website:

"You can't get good sound just by placing the speaker's flat bottom on the floor or on a stand. Because of the large area, low-pressure contact, much of the cabinet's vibrational energy is reflected back instead of being drained efficiently and cleanly down into the floor."

I find this only marginally satisfactory

A site selling Reference Points products (http://storesonline.com/site/1609406) claims:

"The sharp cone point couples to the shelf, floor or platform and acts as a mechanical diode, channeling vibration out and preventing unwanted ambient (floor) and stand vibrations from entering."

"Mechanical Diode"???

I guess the idea is that a given weight connected through a smaller brass point focuses energy being produced internally into whatever is below it. A massive maple platform is rigid to a point but has the capacity to absorb or dampen at least some of this energy, thus "draining" internal vibration "away" from speaker or equipment cabinets.

In the reverse direction, the thick slab of wood absorbs some of the energy from the floor or shelf and keeps it from entering the gear from the bottom up. The overall thickness and weight of these platforms keeps them from resonating like the back of a violin or guitar, but the resonant properties of the wood work instead to absorb and dissipate energy as wood fibers move slightly adjacent to each other - I assume generating some heat in the process.

06-16-09: Jrb25
How does a platform or brass footer "drain vibrations"? Do vibrations act like heat or fluid and flow through materials? Wouldn't footers actually prevent propagation of vibration from an external region (like the floor) to the platform and component in question? Exactly where do these vibrations originate, and what direction are they moving in? Is "isolation" a better way to think about it?

Obviously I am confused about the vibration drainage concept (and a bit skeptical). However, I have heard differences myself, but mostly for spiking speakers to a floor, where the speaker itself is doing the vibrating.

from my experience sometimes the original speaker feet can do a good job of keeping the floor-borne vibrations from reaching the speaker cabinet. There are a few speaker manuf who carefully select the speaker feet. Most do not perhaps knowing the customer is going to use some after-mkt solution. So, chances are very high that the speaker feet will need to be addressed.

Where do vibrations originate? They originate in the electronics itself. Current flowing thru electronics generates an EMF & that causes components to vibrate which eventually couple into the chassis, CD player drive is mechanically rotating & passes its vibrations into the chassis, power xformers vibrate (& even hum), if the chassis is not isolated well then floor-borne & air-borne vibrations get coupled to it. So, vibrations are everywhere & they can be destructive to audio playback.

How does brass drain vibrations? This is my understanding - Brass is an alloy of copper & zinc & the crystalline structure of this binary pair makes it a very good electrical & thermal conductor. WHen the flat portion of the brass cone is couple/attached to the underside of the chassis the vibrations in the chassis find a low impedance path. These vibrations create heat in the brass structure that is dissipated & the rest is conducted away from the chassis by the metal into the rack shelf (the pointy end of the brass cone is coupled to the rack shelf). Since the pointy end of the brass cone has a very small surface area the vibrations from the rack shelf find it hard to enter the brass cone - it acts like a high impedance point. Hence the analogy to an electronics diode wherein the brass cone is called a mechanical diode as it allows vibrations to drain from the chassis into the rack shelf but does not allow vibrations from the rack shelf into the chassis.
If you read Audiopoints' & Mapleshade's website you'll read that the purity of brass is important i.e. the alloy should be kept binary as far as possible. The reason for this, according to my understanding, is that addition of lead or tin or nickel reduces the thermal & electrical conductivity dramatically making it less effective as a cone. The mechanical strength is increased by the addition of these other metals but it seems that varying the content of zinc alone can yield a strong enough brass for audio use.
(someone correct me if I'm wrong. Thanks.)

Jrb55 and knownothing, good questions and points. In my somewhat limited experience with the mapleshade boards, I can say that the boards on the floor alone sound better than my floor by itself, and with my own brass cones under the boards things sounded even better. Has anyone tried different brass cones under the mapleshades, or did you go straightaway with their brass footers?
I can't say for sure if there's drainage going on or not, I can say there seems to be less vibration, hence the cleaner articulate sound.

I use two maple cutting boards sandwiched between two sets of grade 25 tungsten carbide ball-bearings under my 96lb. speakers. Removing the Brass 1/4 x 20 threaded cones that came with the speakers, and putting the 1/2 inch grade 25 tungsten carbide ball bearing in the empty slot works better in my system than brass cones under the maple butcher blocks. So maple and tungsten carbide ball bearing work very well together. This a form of floating your speakers.

Hi jejaudio, where's a source for ball bearings?
Thanks