Home made equipment isolation platforms.......?

So does anyone know what sort of frequency vibs we are trying to absorb/dissipate ?

Maybe then we could find a material to match......

 

It's interesting to copy from a DIY point of view because you could use more/less, thicker/thinner bands to adjust the rate of resonant frequency damping to suit different turntables. I say 'only' turntables because I'm not convinced it is really worth it for CDP's unless the transports are useless to start with.

 

Thats the way I see it, yes.

AS I understand it the balls act as a kind of valve, so the vibrations are transmitted down through the cd player body through the cones, thus vibrating the balls..."dissipating" that energy.

Likewise the air-bourne energy (if I might call it that) is unable to enter the supports ...for the same reason. (its minimised I should add ; you never get rid of it completely).

Thoughts anyone?

 

Well ok if you must.....


no laughing mind!




http://s134.photobucket.com/albums/q115/davidf_photo/?action=view&current=Picture2016copy.jpg

 

Yes, I know the cones require some ........er, revision....

my first thought when I first an it up was that it was dramatically better. The bass was octave deper (seemingly/IMO etc!)

On second thoughts, if I'm being brutally honest (ive no doudt the scetpics will be delighted to hear).....I wondered.

The bass was far deeper but the presentation also seemed to have lost soemthing.

Your comments Mark about which frequencies we are trying to avoid are probably very valid ones.

More work needed!



edit;on second htoughts , it has worked quite well!!

 

I have been thinking up a design for an isolation table recently too.

My conclusions:
A mechanical suspension system with the component shelves being suspended by an elastic material is likely to be the most successful, though I have no evidence for this. The main problems with this are that I can't think of a way to build a rack that would not look like a dog's breakfast, also the lifspan of the elastic would worry me.

Therefore a more traditional route should be looked at. It is my view that an equipement rack should have (1) great mass (2) isolation features (spikes and/or gel/air seperators).

I came across Tony Gees design http://www.humblehomemadehifi.com/Flexy_Ref.html which has some of the characteristics that I was looking for, but I feel that significant improvements can be made relatively simply. The advantage of Tony's design primarily lies in its great mass and rigidity.
The whole table/rack can be isolated from the floor by making the legs into spikes, or using the round headed nuts if the table was to be placed upon a hard surface.
Rather than use Hawpathon (which is expensive and hard to get hold of) in the shelf sandwiches, I would use steel shot, which is readily available from shot blasting companies, I would also place a copper mesh sheet, or similar in the sandwich and earth each shelf. The steel shot and the copper will conduct RFI nicely away. Whether this is an issue or not is unclear, but it is a simple solution and cannot hurt.
So we have mass that prevents movement, spikes that prevent vibration, grounding that prevents RFI.
The only isloation technique that we have not used (except the suspension method which I had ruled out) is the use of gel feet or an inflated air tube cushion. I propose to seperate my equipment from the shelves by placing them on an MDF plinth supported by Sorbothane feet, or a partially inflated bicycle inner tube. My equpiment is quite heavy 10-20kg each, so I would need the 2" Sorbotahne feet which are not cheap.

My idea is based upon the mixing of a multitude of techniques. I have no idea which are the best, and if indeed there is any scientific evidence to say that any/all are beneficial. It is an elegant solution that will look the part in a clean sophisticated way.

If you like, you could do without the MFD plinth and just use the Sorbothane feet attched directly to your equipment, or you could substitute the MDF for black marble pieces that would add a look of quality and style.

If you were insistant on utilising the suspension technique, it should be possible to suspend the MDF/marble plinth from the shelf above using an elastic material.

Feel free to add your comments about this design.

 

Hi Michael,

Thanks for your thoughts.

Firstly, I live on my own so style/grace and elegance are really the last parameters on my mind.







My lounge has become an acoustic research centre also stuff changes so fast that it is pretty pointless getting it too nice.

What I have done is "designed" with simplicity in mind. Someone once said to me (actually my technical drawing teaching from school days....) "simplicity is the essence"......a phylosophy (IMO) worth adhering to generally.

i've used oak predominantly for cones, chosen for its absorbtive property, ease of working and its flexibility........+its availabiillity.

The plinth was actually made out of soemthing unidentified ....actaully the remains of a mates sofa (you out there Peter?) which I am told is a hardwood. It may have been better made out of oak (I suspect the wood is actually Sepele) but that was too hand.

Ive used mdf in the past but have read that it is not really a good idea.....tends to "sap the music"......I'm not sure.

Again Ive never really got into Sorbothane because its dear and all materials have to be economical for me.

I've toyed with the"suspension" ideas but can't see a way (yet) of incorperating it as a simple modification.

I respond to your other points in a bit!

Thanks for your interest.

BTW the pinth above has given a noticeable improvemnt ......allround.

 

Michael,

That rack is IMO only interesting in it's pointless complexity The chap has gone to a lot of trouble sandwich damping materials within the ply shelves and has then bolted the whole thing together with massive thread and nuts, essentially coupling the whole thing together negating any chance of the damping material within the shelves from doing anything. He also missed the opportunity of copying Townshends design by having the inner shelves suspended or hanging from the outer support/top shelves. I'd stick to to a more basic design and mess around with feet instead if I were you.

 

Wow I guess we could try pretty much anything in a simple form or somewhat complex. I guess the sand and shot dissipate the vibs not unlike David's balls I think the sand/shot stand looks fab!

A bit short on play time myself I need to experiment with quick simple things.

Back to the ball thing, (Cheers David for the pics) I was thinking, would not different size balls dissipate different frequency vibs....

So if we had say a set of cones incorporating, say 3 or four different sized balls in each foot, more frequencies should be knocked out the equation, if my thinking is on track.

Bit tricky putting in to words what I'm now thinking, if we have a little vibration, all by its self, pushing and pulling away on a circuit board and we dampen it by gluing it to a lump of sorbothane, would this not hinder the pushing and pulling vib, causing the circuit board a tiny amount of internal stress, as it can't push pull so easily now.

Where as if it was allowed to move freely, and maybe the push pull action was sucked away (possibly by a ball or three) the board would be under less stress.

Oh the playing is endless, maybe a 'DavidF' cone on a sorbothane base. Sorry just thinking in writing. Have to start playing soon, plenty of ideas


With the suspension thing, why elastic, and not springs, does elastic have a much wider bandwith of absorbtion?

 

JCL: I agree. It had occurred to me that the whole structure was bonded together, minimising some of the damping effects. This was why I was proposing to add secondry plinths on Sorbothane feet. Tony's design is very aesthetic, and its theory is largely based upon the total mass of the rack. How much the shot/sand filling would dissipate vibration, I am not sure? You could easily decouple the smaller shelves and have them resting via spikes on a narrow shelf connected to the three inner rods , but perhaps this is going too far?

My design (still early stages) was based upon using as many tecniques as possible thereby ensuring at least a certain level of success. So long as this can be done simply, then there is no harm done.

I still like Tony's design, though I agree that it is overly complex. It is stylish though, and HEAVY.

As far as MDF goes, I have no evidence that it is better or worse than other materials. I have seen expensive isolation platforms that are made from this material. The designers were claiming that as MDF was a formed material made of tiny fibres, vibrations travelled through it a lot less easily. Have you noticed that a sausage takes a lot longer to cook than a steak of the same thickness? Heat is caused by vibrating molecules, I think?

Best wishes to you all.

Michael

 

With regard to possible suspension materials, I again have no evidence to suggest that one material is better than another. It is only my gut instinct that makes me think that a metal spring could easily transfer vibrations when it is taut. Maybe elastic would too?

 

on the threaded rod nut design ...the idea is that the nuts are kept loose so the whole remains stable but has some flexibility.

As you say if it done up tight it negates some of the benifits.

 

Very possible but would you trust you cd player to a piece of suspended elastic?

 

yes, I think they do

In my experince this doesn't work, didn't do anything any good at all.

i certainly have reservationsabout soft damping materials

I don't think is is an issue

as above

another thing to work on, agreed!

again, makes quiet a complicated design though!

 

Hmmm, maybe its matching the best size ball to equipment and ears then

I've only tried the soft stuff, sounded better to me than nothing, yet to try the drain gear

Just a thought, if we suspend on say a toughish elastic, would that not be similar to sitting the gear on a 1/2 inflated inner tube, same sort of elastic bounce.........

Interesting, if I have a chance in the next week (fingers crossed)I may knock something up on a quick/simple elastic thing

 

DC,

Differenent balls sizes DO give VERY different effects...

to the sceptics...I am as surprised as anyone!

its suck it and see, to see what works best with YOUR kit etc

Don't let me put you off trying sorbothane etc......it might work for you!

yes ,the elastic thing is intersting but , like I say, i acn't readily think of a way of doing it simply......and without the risk of (potentially) crocking my player


Let me know how you get on.......

 

i would have thought the perfect isolation would be a large U-frame with elastic bands hanging and holding a suspended shelf.

all this cones with ball bearings sounds nonsense as all it is doing is decoupling and not vibration absorbing

 

not a bad idea...

again, there are security issues

no,

1) the oak cones absorb vibrations

2) the bass vibrate, thus dissipating the energies away.

 

Found these:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=99692&highlight=

http://www.diyaudio.com/forums/showthread.php?s=&threadid=98576&highlight="isolation+platform"

http://www.diyaudio.com/forums/showthread.php?s=&threadid=69653&highlight="isolation+platform"

Sorbothane seems very well regarded.

 

Try it!







I think when I priced it it seemed expensive