On energy absorption - energy dissipation - and Hi-Fi racks

[suri]

truly believe that -

a good rack can take the listening experience to worlds not explored.

sensitive equipment such as vinyl turntables, cd transports, tube amplifiers should be dead to incident energy - either from within or without -

mechanisms create energy with potential to disturb the delicate signal which is sought to be reproduced - likewise, energy produced by the loudspeakers themselves has the potential to induce undesirable resonance in such equipment-

what are the thoughts of members about the science and reasoning behind such things?

i ask, because i see lacunae in our collective minds -

surely, a three hundred pound audio rack may not be able to do the job required of it.

perhaps, those audio racks which cost 3 lakhs INR are really worth the money - if the connoisseur (with the spare cash) really wants to get the best out of his (already expensive) equipment?

 

[arj]

If one is expecting the same benefit out of a rack which people in Europe and the US are expecting they are in for a rude shock !
almost all flooring is wooden which is very very lossy ..and some have carpets too.
India flooring is usually solid concrete so what works there may not be the same here

racks have 2 Major functions ie
- Not allowing floor vibrations to get into the component
-Isolate each equipment so that they do not transmit vibrations to the other components (Especially CDP/TT)

for me. CDPs having something lossy under it which can Absorb Vibrations have worked best and with Speakers and Amps stronger the coupling the better I have liked them

 

[ajay124]

I have a slab of granite lying unused for many years.I was thinking of getting 3 pieces cut out of it,for placing under the cdp/pre/power.Would it be worth the effort?

 

[moktan]

are such expensive racks needed if one uses a computer, dac, amp etc chain for the music...
i would be more interested if someone would point a way out of the unwanted vibrations that furniture beetle larvae make as they bore their way through the wood of door posts and what not...
an empathetic (to the insect not me) lady once told me..what made you think that you were the sole and only owner of your house??

 

[suri]

are such expensive racks needed if one uses a computer, dac, amp etc chain for the music...

for sure - moktan - computers have fans which rotate - hard disks which spin - cases which resonate-

focus! - moktan - focus - is what leads each one to personal truth - if there are a billion people in this world - then, there are perhaps 400 million truths - applied and reacted to - every living moment.

oops! - no, make that 5 million truths - too many (pusillanimous) followers!

 

[ajay124]

are such expensive racks needed if one uses a computer, dac, amp etc chain for the music...
i would be more interested if someone would point a way out of the unwanted vibrations that furniture beetle larvae make as they bore their way through the wood of door posts and what not...
an empathetic (to the insect not me) lady once told me..what made you think that you were the sole and only owner of your house??

Everything we have been granted,including the W's of E are for a finite time.Ultimately the insects get it all.They are the real heirs of all our possessions

 

[moktan]

well for someone who wanted to heat up his room with the thermal outpourings of a class A amp (ask Gobble about the luxuries of living in a cold place)..i (or my notebook) haven't really been threatened by the sonic exuberance of that spinning device..
though i would be beholden if you could kindly point me a way out of the noisy, nocturnal interferences of these infernal invertebrates...

 

[suri]

i would be beholden if you could kindly point me a way out of the noisy, nocturnal interferences of these infernal invertebrates...

you could volunteer for -

Colonization of Mars - Wikipedia, the free encyclopedia

 

[NetFreak]

for sure - moktan - computers have fans which rotate - hard disks which spin - cases which resonate-

One way to avoid is to:

1. Use a NAS to store digital data (Uncompressed formats or loss-less compressed formats)
2. Keep NAS away from rack that contains speakers etc
3. Connect NAS via Ethernet cables to Media player (or buy an AVR that can play these formats directly via network)

In that case, there is no need to worry about vibrations.

CD can provide digital data without any loss in form on PCM, so in a digital system this should not be an issue.

However, this does not take care of issues with analogue sources (E.g. Vinyl).

 

[anm]

pls forgive my ignorance - in my room the rack is placed inside the room. Playing music at decent volume vibrates the air in entire room. I can feel the bass sitting on my sofa. Doesn't this vibration gets transmitted to the equipment directly? Is this vibration too less to be even worried about it? However, in my mind (no measurements) this source of vibration would have much more impact than vibration that may get transmitted via air. But no one even considers this or talks about it.
Can someone pls comment?

If one is expecting the same benefit out of a rack which people in Europe and the US are expecting they are in for a rude shock !
almost all flooring is wooden which is very very lossy ..and some have carpets too.
India flooring is usually solid concrete so what works there may not be the same here

racks have 2 Major functions ie
- Not allowing floor vibrations to get into the component
-Isolate each equipment so that they do not transmit vibrations to the other components (Especially CDP/TT)

for me. CDPs having something lossy under it which can Absorb Vibrations have worked best and with Speakers and Amps stronger the coupling the better I have liked them

 

[sidvee]

pls forgive my ignorance - in my room the rack is placed inside the room. Playing music at decent volume vibrates the air in entire room. I can feel the bass sitting on my sofa. Doesn't this vibration gets transmitted to the equipment directly? Is this vibration too less to be even worried about it? However, in my mind (no measurements) this source of vibration would have much more impact than vibration that may get transmitted via air. But no one even considers this or talks about it.
Can someone pls comment?

You are absolutely right anm. There are also air borne vibrations that can effect equipment - especially tubes. In-fact in Indian settings I think the majority of the bad vibes are airborne (being that floors are poured concrete). Fortunately this type of vibration is - from what i understand - somewhat less harmful that the floor borne kind, but harmful regardless. Anyhow for tubes - tube dampers help and equipment footers (rigid cones, soft cones, ceramic supports etc) and other supports are claimed to dissipate vibrational energy from equipment chassis that are picked up from the air or generated within the equipment itself. Also a well built, vibration isolating rack will prevent the airborne vibration from being transmitted through the rack.
Cheers
Sid

 

[suri]

Playing music at decent volume vibrates the air in entire room. I can feel the bass sitting on my sofa. Doesn't this vibration gets transmitted to the equipment directly? Is this vibration too less to be even worried about it?

@anm - This (energy produced by the loudspeakers) has tremendous potential to create resonance in partnering equipment - sidvee has mentioned them.

on more than one occasion - i have felt large monoblock amps singing like helmholtz resonators along with the music.

and what about (so-called) audio racks? - some of them are superb helmhotz resonators! - especially the closed back ones with thick wooden shelves - in india racks are made with just one purpose, and that is to protect precious equipment from dust - nothing else matters (this brings to mind plastic covers on the seats of new cars -i have seen cars more than a year old with the plastic covers on the whiplash protectors and windscreen visors still in place).

what about those huge diesel trucks? (i live on the national highway) - when one of them passes by at full grunt even my head (and opposite end) vibrate- the cd player, if placed on the floor, vibrates like jelly (very much less when placed on the isolation rack).

quite sure that the need for isolation and energy dispersing racks is as much necessary here in india than in those poverty stricken european countries or (getting-bashed-by-china) U.S.A. -

no need to bother about africa though - there gunfire and machetes create music - and if they are not dead by nightfall, live music is what keeps them going.

 

[ajay124]

Have no idea how much energy is being absorbed or dissipated,but this is what I could manage with left over wood and one day each of hired carpentry and polishing.Open from all sides,even below the 3 units,simple and blending with the rest of the room.I have resisted the temptation of putting a glass top.Cost 1K
ImageShack: Host and Share your Photos and Videos - audiorack1.jpg

 

[hifiashok]

your bryston seems perched direct on body to the rack, not on its feet. feet usually have a little rubber or foam for a soft landing.

i use vibrapods and vibracones.

 

[suri]

Have no idea how much energy is being absorbed or dissipated,but this is what I could manage with left over wood and one day each of hired carpentry and polishing.Open from all sides,even below the 3 units,simple and blending with the rest of the room.I have resisted the temptation of putting a glass top.Cost 1K
ImageShack: Host and Share your Photos and Videos - audiorack1.jpg

where the glass top should have been - there is a square opening- and the feet of the bryston amplifier lie free in that opening -

and that is why the bryston body seems to touch the wood as it sits on the platform?

 

[arj]

pls forgive my ignorance - in my room the rack is placed inside the room. Playing music at decent volume vibrates the air in entire room. I can feel the bass sitting on my sofa. Doesn't this vibration gets transmitted to the equipment directly? Is this vibration too less to be even worried about it? However, in my mind (no measurements) this source of vibration would have much more impact than vibration that may get transmitted via air. But no one even considers this or talks about it.
Can someone pls comment?

Hey I am not the expert..but this impacts the equipment in a couple of ways

-Indirect..where it impacts the floor/walls/rack etc and this needs to be dissipated before it hits the equipment. Most racks are able to do that (Based on the resistance to vibration)
-Direct- ie the equipment itself is shaking..only way this can be countered is by the natural damping in the equipment as well as how it is able to transfer the vibration below. Hence CDPs being having well damped casing as well as sitting on lossy footers is usually advised.

I am not really too sure about the Helmholtz resonator part..thats a bot too complicated for me


But there is a limit to all this..and too much damping makes the sound lifeless ..eg just try pilling up Telephone directories/dictionaries on top of a CDP..initially the bass/midrange will improve and then the music starts getting lifeless !

 

[anm]

hmm - still do not understand how to prevent bass impact (the air movement) from shaking my equipment.

 

[ajay124]

@hifiashok/suri
I did not have enough wood for the 3 floors of the rack.Therefore the hollows in the middle.In the case of the cdp/pre the supports are resting on the side panels.The problem is with the power amp,where the supports are closer together.The supports are hanging free in the hollow section,and the body of the power amp is perched on the side panels.I had planned to get glass panels for the three floors and the top.Now I am more inclined to simply placing a granite slab under the power amp,stretching from end to end.Best support and isolation I can think of with the present rack.But I have not been able to coax a workman to come to my place,and cut the granite.Chandigarh is in the middle of a 'rebuilding' boom and it's tough to find workmen.
Any other ideas?

 

[arj]

hmm - still do not understand how to prevent bass impact (the air movement) from shaking my equipment.

You cant. best option is to put the equipment faar away. ..other than the cost of real estate either your ICs or Speaker cables are going to be pretty lengthy

 

[anm]

in my current listening room, the balcony is next to a side wall, so it should make only 2-3 ft of extra wire to move it behind a concrete wall. but remote would stop working, have to open the door and say hello to my neighbors to change a cd or record.

Instead can there be closed designs that prevent the direct impact, but also do not turn up to be sound boxes themselves. How about a closed rack with few (or a lot of) ports on side/ rear or bottom to prevent from air being trapped inside.