Help Total Confusion

Pbb, i find your comments interesting. If heavy footfalls / extremely powerful low frequency output can cause a digital source to skip ( which i and many others have experienced ), wouldn't lower level vibration potentially cause the player to potentially mis-track and / or use more error correction ?

I've also experienced a MAJOR change in system sonics simply by changing racks. I would not have believed it if i had not experienced it first-hand. This was NOT subtle nor was it "for the better". After shelling out hundreds upon hundreds of dollars for a new rack in one of my systems, i was NOT pleased with the results AT ALL. The rack i was using weighed well under 40 lbs at most. The new rack clocked in at 150 lbs. Nothing else changed as i kept all of the same components and cabling, etc... I can see no reason for a change in system sonics when changing a rack other than the equipment being "sensitive" to vibrations and other forms of energy transfer.

My brother, who comes over frequently and listens with me, commented almost instantly that the system sounded like "mud" i.e. slow, heavy, lacking air and space. He stated this the first time that he heard this system with the new rack installed. This system normally had very powerful bass with excellent "slam" and phenomenal harmonic structure and air. I had noticed the same thing but did not know if i was imagining things or not. I did not want to think that my "new investment" had taken me several steps backward. Changing the amp tilted the tonal balance back towards neutrality but the system was still lacking the finesse that it once had. Going back to the original rack solved the problem. Once i had done that, the system was back to sounding somewhat lean but now had the harmonic structure and air that i was used to. I then switched back to the original amp i had in the system and everything was back to normal.

I think that this system change was the result of several factors working at one time. The added weight of the rack changed the resonance of the floor. You see, this system is on a suspended floor and the floor DOES vibrate. By changing the resonance of the floor, the amount of energy coupled from the speakers was also influenced. Besides that, the rack was noticeably taller than original one being used. Since the speakers in this system are omnidirectional, i have no doubt that this might have affected the radiation / reflections in the room, changing the amount of direct vs reflected sound that i was hearing. I will not deny that these factors MIGHT have played a very important part of the differences that i heard.

Having said that, i began changing shelves in a couple of different racks using different types / weights / densities of materials for the shelves. Some shelves made a marked difference in the sound of the system. This leads me to believe that the ability of a shelf to transfer or absorb energy DOES influence the sound of a system. Whether you as an individual have experienced this or want to acknowledge the potential for variances in sonic reproduction would be dependent on your mind-set. I know that i was VERY much a "doubter" when it came to racks, speaker cables, interconnects, power cords, "tweaks", etc... a few years back. Being an electronics professional by trade tells me that none of this type of stuff "should" affect anything. Personal experimentation and having an open mind ( not initially though ) has made a world of difference. Not only is this difference apparent in my attitude, it is apparent in the performance of my system. Sean
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I have a wide low Plateau rack between my speakers and it works very well. My ESL panels extend up a lot higher than the rack, which probably helps, and I also use a room lens, but behind my rack instead of in front, which works great to focus the imaging and tighten the bass. (Those room lenses really can work wonders!)

One thing to consider for those who have the rack close to the front wall -- that's a location where the bass frequencies will be strong and can potentially induce mechanical feedback into your equipment. Moving the rack up a couple of feet from the wall will usually result in a lot less bass hitting the rack. If you have a turntable, this could be an important consideration...

Here's my problem. I really can't get the speakers more than a couple of inches in front of the rack. But I could get each speaker a couple of feet away from the sides of the rack. To put the monitors two feet in front of the rack would mean moving the speakers every time I listened. The speakers weigh 75 lbs apiece and the stands weigh 100 lbs. apiece. I would then be listening at a total distance of about 5 feet--that's really nearfield!

If the speakers are a couple of inches in front of the rack, and are not excessively toed in (so that any sound waves going towards the rack are greatly attenuated) then I don't think you'll have any problem.
Also watch out for the side walls ... those primary reflection points on the side walls will kill imaging. Don't put the speakers overly far from the rack and end up with side walls too close.

All that said, I wouldn't buy a rack without a home demo. It would be like riveting your speakers to the floor before listening to them and hoping that you'd put them in the optimum place. Placement make more difference that the quality of the equipment itself in my experience.

I have read that if you must do this, keep the rack lower-profile vs. taller.
No experience with this myself, but from those who have tried it that's the advice given. YMMV