Why Does A Concrete Floor/Spiked Metal Rack...


suck all the warmth and life out of my system?

I have been thoroughly dissatisfied with my hi-fi system for the good part of a year now and I have been unable to until recently to put my finger on the problem. In a nutshell, almost every CD I would play would sound bright and harsh and bass light. The top end and upper midrange would completely overwhelm the bottom end. I have experimented with all sorts of tweaks and in particular various isolation devices, and although I was able to achieve minor changes to the tone the overall top end brightness and lack of bass was still evident.

I was enjoying (as best as I could given the problem!) a listening session and wracking my brain (for the ten millionth time) for ideas on how to make my system work better, when it suddenly dawned on me that I had these small plastic/hard rubber? cups that might be ideal to place under the rack spikes as a last ditch attempt to solve the brightness issue. With the music still playing I carefully tilted the rack enough to slip the cups under each spike on the four corners of the rack, thus de-coupling the rack from the concrete floor. They were a perfect fit and the effect was both immediate and DRAMATIC. The system was for the first time tonally balanced, the bass response increased, the sound stage widened, the noise floor dropped, there was greater depth, increased clarity, and most importantly the brightness and harshness had completely disappeared!

I was firmly of the belief that audio racks should be coupled to the floor for stability and assist with the reduction of floor vibration eminating from the floor. My rack is a rigid design composed of tubular steel and every cavity is filled with sand in order to reduce any possible ringing. The rack is supported by four large adjustable screw in spikes which penetrate the carpet and couple the rack to the concrete floor beneath. The components are supported on MDF shelving. What I discovered this weekend is that this rack/floor interface was completely sucking the life out of the system. Upper midrange and top end frequencies were being accentuated at the expense of the lower mid range and bottom end, thus producing the fatiguing brightness and harshness.

Can anybody explain to me in laymans terms why this occurs?
unhalfbricking
I think a company such as Sistrum has addressed the directionality of cones/spike. I think it is safe to say most of the mechanical vibration is drained in the direction to the point of the spike.

As for seismic vibrations, that is a physical vibration where its effect on stereo equipment is minimized when attached to solid matter rather than a soft one. Seismic waves will travel right through solid matter. If I remember correctly, seismic waves causes most damage their P and S waves are slowed down and impeded from completing their waves.
From the Audio Point website:

The unique design of the Audio Point displaces the focal point of the resonant energy to a virtual point below the tip of the Audio Point. Physics dictates that this virtual focal point creates a natural high speed channel through which resonance energy will flow. The result is the relocation of the resonance energy into the surface upon which the Audio Point is resting.

Statements such as this may make sense to some people, but it sounds like mumbo-jumbo to me. Furthermore, as far as the directionality of "resonant energy", if I use an Audio Point the pointy end faces downward, but if I use the same Audio Point in a Sistrum rack some of the points face upward (into the component) and some face downward. Is the rack feeding "resonant energy" into the component? I don't mean to sound obstinate, nor am I disputing peoples' testimonials to the effectiveness of Audio Points/Sistrum, but their explanation of how their product works is weak.
Onhwy61, I also was curious about that same thing, with the points going upside down on the racks and platforms, so I asked about it.

The explanation is that when the points are used upside down on the rack or platform, they are working in conjunction with the platform and another audiopoint in the other orientation directly coupled underneath it, and not in a "stand-alone" configuration.

According to the factory, this changes the behavior of the upside down audiopoint on top, to behave in accordance with the overall system to bring the vibrations downward to mechanical earth ground. It is not done in just a "willy-nilly" or "hopeful" way where they are "guessing" that it will do this. It has been designed by scientific theory, tested, and found to work. That is one of the things that sets Starsound products apart. They are engineered products, and not "garage" products. There are degreed engineers that are producing these designs.

To address your questions about vibrations "back-feeding" up the cones, they do not. The geometry and design of these Audiopoints precludes back-feeding of vibrations, when used in the proper way that is stated in the directions. What will happen though, is that if the entire floor is going up and down, the whole rack will go up and down with it. They can't stop the floor from vibrating, but they will not feed the regular vibrations back up into the equipment. If the floor is that active, then there is a floor problem, not a rack problem. Addressing the floor problem by bracing is the way to attack that, not by compromising the performance of the audio rack. If there is a major floor inadequacy and it is not possible to address it, like in a rental apartment, then maybe the Sistrum products aren't the answer to that. However, in a proper listening environment with a firm floor, they will do better than any de-coupling device.

I might add that the Aurios are not de-coupling devices, but are actually a form of coupling device that uses a ball between the cups that allows lateral vibrations to be dissipated by the minute "rolling of the ball". So you are actually doing some type of coupling right now with your Aurios. But with a different kind of design that may not be as effective as the Audiopoint design. If you like the Aurios, perhaps going further into even better coupling would yield even better results. Just a thought.