Why does a decent rack make a difference to sound?

Posted by: Adam G on 31 March 2004

After building myself a half decent hifi rack, I noticed improvements in the sound quality almost straight away...
Why is this? I know that hifi racks are supposed to make a big difference in sound quality, but wondered what the technical reasons behind this were...
Any ideas anyone?
I own a NAC 102, NAP 180 and CDi.
The rack consists of 3x 30" lengths of toughened 10mm glass, with glass beads stuck on the bottom of each shelf with silicon. Glass beads are being used as "feet" sitting on top of a concrete block on each side. Then another 2 concrete blocks for the next level, followed by another shelf, then the same setup again.
Between the glass shelf and the concrete block "legs" of the next shelf, I massacred my mothers yoga mat so that the concrete didnt break the glass.
Will post a photograph later today when I get home...

Adam
Posted on: 31 March 2004 by Laurie Saunders
quote:
Any ideas anyone?


When you find out, let me know

laurie s
Posted on: 31 March 2004 by BLT
OK, it's a long time since I did any engineering design, but I will put forward some theory.
Many electronic components are microphonic, a simple way to show this is to tap thermionic valves in a high gain part of an audio circuit - a "thunk" can be heard through the speakers. Items like CD players and especially turntables which have a mechanical component are obviously affected by vibration. Having established that vibration can affect the sound output of hi-fi equipment we need to look at the potential sources of vibration. These are internal and external. The internal vibration sources are mainly from the transformers and from mechanical mechanisms such as Turntable and CD motors. The external sources can be from anything, the sound that the Hi-Fi itself creates to a road drill in the street.
The two general approaches taken by designers of Hi-Fi racks are to either isolate the equipment from all external sources of vibration (i.e. Thownsend Siesmic Sink) or to provide an path to dissipate and control internal and external vibration (i.e. Mana etc)
Of course there are an infinite number of ways of implementing these approaches and often elements of both will be used.
Posted on: 31 March 2004 by Geoff P
The only comment I would add is there is no "one true way" with this.

If you had the time and the money you could experiment with all sorts of isolation designs from the "allow it all to wobble" to "bolt it to the floor and use air ride platforms" approach.

All will sound different. Then you can start playing with the stacking order of the kit on the racks which again will bring subtle but hearable changes.

That said some rack designs manage to get more of it "right" than others but usually at a price. I would bet though that the proud owner of a nicely designed and completed "DIY" rack would take a lot of ocnvincing that anything he has to pay money for is worth it.

If you are happy with the "sound" just sit back an listen
GEOFF
Posted on: 01 April 2004 by Laurie Saunders
quote:
If you are happy with the "sound" just sit back an listen


..trouble is...there is that nagging feeling that there may be something even better

laurie S