2. misc-audio
  3. 1064803157

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

Showing 6 responses by viggen

viggen
838 posts
 
In layman terms, the order of execution might not be correct.

In some circumstances, totally isolating the system can cause it to sound sterile. However, I am not sure this is the case since the rack/component interaction hasn't been properly described. Although, you do seem to try to kill vibration with your application of sand and mdf boards. I think this is more relevant than the rack/floor interaction.

Also, generally, in applying draining and deadening techniques to system, one wants to drain vibration from component to something that is "dead". You seem to have this backwards. And, this seem to lessen the effect your rack/floor interaction has on your system's sound.

Lastly, as the rubber cup is under the rack now, vibration is not drained as expediently as when the rack's spikes are directly touching the bare floor. This ought to slow down the velocity of vibration traveling in your rack if there is any significant vibration still moving around. I don't think this is very relevant since you got the sand and mdf applied to your rack.
viggen
838 posts
 
Yah, you tell'em Dave!
viggen
838 posts
 
Face it, most racks such as Target and such that uses hollow tubing and a mixture of materials from metal to wood to plastic is not going to "drain" anything but the life from the music. Those kinds of racks are designed to be filled with sand to minimize unwanted resonance and mechanical vibration. The rubber footing further reduces vibration in this kind of set up.

If you want to drain vibration, first make sure you got the right rack ie. Sistrum then worry about the right spike that further enhances vibration draining. Otherwise, the spike is only good for isolating the rack from the earth.
viggen
838 posts
 
Oops, it is more correct to say vibration is "altered" not "minimized" in my thread above. Only resonance is minimized.
viggen
838 posts
 
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.
viggen
838 posts
 
Don't forget about gravity.
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