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AV Racks. What difference does it make?

Im not sure i understand what difference your rack could possibly have.

I understand everybody here seems to feel that reducing all sorts of vibrations is important as well.

How is that? its not like 1's and 0's get rattled off the circuit board by vibrations

Whats the point in a better rack? What is a better rack? And how does a $1,500.00 rack make anything sound better? I mean, technically, in depth, can anybody explain this phenominon?

Sounds like a buncha horse pucky to me. Kinda like the kinds new clothing.

Does anybody have a theory of how one AV rack can sound different than another? And dont give me any of that room accoustics stuff, i dont see people talking about which sitting chair is best for sound!!!! :)

"I found that wearing wingtips and khaki shorts really opened the soundstage compared to my nikes and TH bluejeans."

I have a good understanding of electronics and accoustics, but i cannot imagine any way a rack could make a difference.
What is the theory of how a Maplewood rack might sound better than an oak for example?

Do you all use racks and isolation pods at the same time?
slappy
sean
6,231 posts
 
Slappy: I think that you'll find that there are MANY schools of thought as to what makes for a "great rack" ( oooh boy.... ), but there is no single ideology that covers every aspect perfectly. That is why there is such a vast market of products available in terms of racks, isolation, damping, absorption, coupling, etc... I think that this is something that people have to learn / experiment with on their own and learn from that i.e. the hard way. It seems to be about the only way that people "open their minds" when dealing with controversial subjects like this.

Unfortunately, this can be both expensive and time consuming, so try and learn as much as you can from others and be selective about what you spend your money / concentrate your efforts on. There are quite a few excellent suggestions in various threads here on Agon and at AA made by people that have spent the time and money to learn the hard way. Let their experiences work for you and i think that you'll find that you are both happier and not quite as poor as others that aren't quite as open to suggestion. Sean
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slappy OP
903 posts
 
Thanks Sean, however, i think i have made my mind up, because i think i have the perfect solution for an AV rack

Get a bunch of paint-mixers and place the audio equipment into the clamps of these babys and turn em on!

they will be shaken so violently that no airborne vibrations will make any difference!:)

HAHAHAHAHAHAHAHAHAHAHAHA

just kiddin!
viggen
838 posts
 
Hey Sean,

The purpose of understanding natural resonance frequencies of different materials is so you can combine different materials to mechanically/sympathetically minimize vibration (instead of amplifying it.)

If you examine the Symposium shelves where it sandwiches materials of varied densities together, you'd see how this phenomenon works. Lexus does something similar with their car bodies and IBM does something like this with their high end server/storage cases.

With my speakers, I have good luck using the wood/graphite/granite to tailor the speaker to sound the way I like it. This reduced a bit of boominess in the lows and LOTS of hashiness in the highs as well as expanding the soundstage.

So, when using your vibration measurement machine, try using it on a combination of materials such as rubber on wood or metal on marble etc, and, ofcourse, tune with your ears.
eldartford
4,262 posts
 
Materials don't have any natural frequency. They have properties like mass, elasticity, etc. Natural frequency is determined by the shape into which the material is formed, how it is attached to other objects or otherwise damped, and the abovementioned mechanical properties. Consider that you can make a whole belltower of bells, playing different notes, out of the same metal.

To be specific, the fiber board that speaker enclosures are usually made of can ring like a bell, or be completely dead, depending on the bracing and damping material included in the design.
viggen
838 posts
 
El, materials do not have natural frequencies, yet it is the form that determines its physical properties? So your bell tower can consist of bells made of wood, metal and plastic and they will all sound the same so long as their shape is idential... absurd.

Well, there is a difference between natural frequency and natural RESONANCE frequency. This concerns the differences or sameness at which vibration or waves move through the material(s). And, the key part is, the more sympathetic the natural frequency is to the vibrating waves (catylist), the more compelling waves will be created thus maximizing vibration.

Bells and tuniing forks specifically work in these methods which have opposite results in what we want to achieve concerning audio racks.
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