Equipment isolation and vibration damping.

[bdiament]

Hi Dave,

 

...I don't think it matters much whether the curved cup is on the top, or bottom. You can experiment, of course...

 

If anyone ever measures this, I'd be very curious to know. I could be wrong of course but I suspect there will be an advantage to bowls on the bottom.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

[Duke40]

Hi Duke40,

 

Those are some cool-looking platforms!

 

 

 

I've had young mothers place themselves between me and their children as they passed.

Similar things happened when I was testing open cell foam at a local crafts type store. I needed some foam for the baffle I was making to go between my microphones during recording sessions. I already had the closed-cell foam for the core. Now I needed some open cell foam and I wanted it to block as much treble as possible. So I held a sheet of foam up against my ear while rapping on the store's metal shelving with the other hand as I listened through the foam. Couldn't blame folks for thinking they should keep their distance. ;-}

 

Barry, thanks for the compliment on my DIY platforms ... I have 3 sets of Townshend springs, several sand filled doorstoppers and a heap of Aluminium slabs ... just for my headphone rig.

 

LOL at your crafts store story. I was at the hardware store with my sister ... and when people gave me funny looks when I was rapping my knuckles on different materials , she just called out "don't worry ... he is special needs" or "he took too many blows to the head as a boxer".

 

I suppose if she had actually called out "Don't worry ... he is an audiophile !!!"

they would not have understood. Good times.

 

Once again, I enjoy & appreciate you posting your wisdom on this topic ... I think isolation is an under appreciated area ... not enough attention is paid to it.

 

John

[YashN]

I have 3 sets of Townshend springs, several sand filled doorstoppers and a heap of Aluminium slabs ... just for my headphone rig.

 

These ones?

 

 

Review at PF.

 

Capabilities (from PF as well because the official domain expired):

 

From the Townshend Website:

 

• Eliminates structure-borne feedback between speaker and vibration sensitive equipment.
  
  
   
  
  
   
  
  
• Enhances clarity throughout the whole frequency range.
  
  
   
  
  
   
  
  
• Improves bass definition.
  
  
   
  
  
• Produces a wider and deeper sound stage.
  
  
   
  
  
• Neighbour friendly high level listening.
  
  

[JohnSwenson]

A lot of neat stuff going on in this thread.

 

On the subject of the "flat with round edges", that does give very good isolation, yes it doesn't have a particular resonance, but that is good! Go back to the thought experiment for why the flat is good. The problem is that it is like a pencil standing on its point, it's an unstable system. The slightest tilt relative to gravity and the device slides to the edge and sits there, it's better to have a gentle slope that tends to keep it centered.

 

The "bowls" do not have to be large, just a shallow curve, in actual operation the distance things actually move is tiny so large bowls are not necessary. A good compromise seems to be a shallow surface with a rim, in normal operation the ball sits in the center and is moving microns at a time. The rim takes care of the situation where you push a button or try and pull a cable off etc, it keeps the device from moving very far. In normal operation it is not touching the rim.

 

I was thinking about commercial items that could be used for the "bowls" that would work well and are inexpensive. What I came up with are concave optical mirrors made of glass, they are hard, have highly accurate surfaces and highly polished. At first thought I thought they would be too expensive, but I found several places on Amazon that are selling concave glass mirrors in the 35-50mm diameter sizes for $2-$3 each. You can get focal lengths from 50mm to 250mm to try different "steepness" of curves. I haven't tried these yet but I'm planning on getting several and giving them a try.

 

On aluminum I did a bunch of experimentation a few years ago and found that THICK aluminum has some wonderful properties, it is stiff enough that it doesn't have much in the way of bending modes. It damps compression waves enough that it does not support modes running through the material. It DOES support surface acoustic waves, which gives rise to the "ring like a bell" mode. But these only become a problem if you have parallel surfaces that support standing waves. It turns out you can eliminate the standing waves by "breaking up" the surface. I like to do this by taking an engraving pen and drawing some "swoopy" curves on the surface, they diffuse the surface waves thus preventing standing waves from forming.

 

A properly treated slab of aluminum gives a very faint "tink" when you hit a suspended piece. If you hear a "thunk" or "thud" it is not stiff enough and is having some bending modes. Anything high pitched but lasting more than a "tink" means you don't have the surface waves properly tamed.

 

There are actually some amazing electrical properties to thick aluminum as well. They are superb electrical AND magnetic shields. Any decent metal piece works well as an electrical shield but don't work beans as magnetic shields. Most people wind up using things like MU-metal and other specialized magnetic materials. BUT these have some bad properties for audiodom, they tend to saturate easily, limiting their effectiveness, and some of them tend to have time delay issues as well.

 

Thick aluminum has such a low electrical resistance that eddy currents are produced inside the aluminum that counteract external magnetic fields, significantly attenuating their passage through the metal. Because aluminum is not magnetic, it doesn't saturate, so the magnetic field attenuation is affective from very tiny fields to very large fields. It's effective from low frequencies (60Hz hum) up to GigaHz range.

 

These properties of aluminum are why I use thick panels to make enclosures for my electronics.

 

John S.

[bdiament]

...I was thinking about commercial items that could be used for the "bowls" that would work well and are inexpensive. What I came up with are concave optical mirrors made of glass, they are hard, have highly accurate surfaces and highly polished. At first thought I thought they would be too expensive, but I found several places on Amazon that are selling concave glass mirrors in the 35-50mm diameter sizes for $2-$3 each. You can get focal lengths from 50mm to 250mm to try different "steepness" of curves. I haven't tried these yet but I'm planning on getting several and giving them a try...

 

Hi John,

 

By all means try them. I'd be curious as to what you find.

I'd be wary though of performance with heavy components simply because my experience as an amateur astronomer has taught me that glass flexes.

 

Best regards,

Barry

Soundkeeper Recordings

http://www.soundkeeperrecordings.wordpress.com

Barry Diament Audio

[Jabs1542]

There are actually some amazing electrical properties to thick aluminum as well. They are superb electrical AND magnetic shields. Any decent metal piece works well as an electrical shield but don't work beans as magnetic shields. Most people wind up using things like MU-metal and other specialized magnetic materials. BUT these have some bad properties for audiodom, they tend to saturate easily, limiting their effectiveness, and some of them tend to have time delay issues as well.

 

These properties of aluminum are why I use thick panels to make enclosures for my electronics.

 

John S.

 

Thanks for the insight. I have an APC UPS for my CAPS server and other computer gear that generates a fair amount of EMI; this has bothered me ever since I measured it. I think I'll make a three sided box (last side, top, right side) of 1/2" thick plate to go over the UPS.

[YashN]

Oh, while I was at the hardware store I found some sand filled steel doorstoppers (with rubber base) marked down from $10 to $1 each, so bought a heap of those.

 

After taking care of speakers ... I find my DAC's tend to benefit the most , then source, then amp.

 

Below photo's are an example of DIY isolation platforms from my headphone rig located in the man cave ...

 

[ATTACH=CONFIG]19241[/ATTACH][ATTACH=CONFIG]19242[/ATTACH][ATTACH=CONFIG]19243[/ATTACH]

 

I am thinking of getting the Aluminium ... anodised.

I believe that will narrow the "resonance band".

 

Oh, I experimented with footers a lot ... decided I actually preferred at least one slab of 10mm Aluminium directly under a component

 

Very cool 'man-cave', Duke40.

 

Are these the door-stops that we see in the photos? I gather you are placing some on top of your components to prevent some vibrations there?

 

Cool you mentioned the order of where you heard most benefits: I was wondering about that. I thought of doing the amp and the speakers initially, but now, I believe the source should be important too.

 

The thing is, I consider my 'source' to be a three-parter: USB external HDD, iMac and DAC. Hence, if I do the speakers, I'll probably need 3 more sets of isolators quite rapidly.

 

Anodising may well be good: I see Symposium did anodise their aluminium.

 

If that's not too much to ask: do you think the benefits for each type of component are the same, or each benefits the sound in a different way?

[YashN]

LOL at your crafts store story. I was at the hardware store with my sister ... and when people gave me funny looks when I was rapping my knuckles on different materials , she just called out "don't worry ... he is special needs" or "he took too many blows to the head as a boxer".

 

I suppose if she had actually called out "Don't worry ... he is an audiophile !!!"

they would not have understood. Good times.

 

Picture me a few days ago at the store, pulling items off the shelves one by one, moving them to other shelves to reach the items further at the back, and then putting back most of them.

 

I didn't bother to look at other people's reactions

[YashN]

This is iteration #1. It works.

That is precisely the reason why I'm using this design. It works. It works superbly.

 

No doubt it works, now let's try to optimise it in v2.0!

 

Actually, I believe it will technically make for an absence of isolation. The ball (or more properly the supporting shelf) is not going to move *that* much.

 

I think it is OK if the balls doesn't move that much: this allays a lot of my fears of gears falling off at the edges. On the other hand, if you follow John's gedankenexperiment above, we agree with your initial assertion that you would want the ball to be able to move as freely as possible.

[Daudio]

concave optical mirrors made of glass, they are hard, have highly accurate surfaces and highly polished... I found several places on Amazon that are selling concave glass mirrors in the 35-50mm diameter sizes for $2-$3 each. You can get focal lengths from 50mm to 250mm to try different "steepness" of curves. I haven't tried these yet but I'm planning on getting several and giving them a try.

 

John,

 

Sounds interesting. Care to share some links ?

 

 

On aluminum...

 

Too bad I scrapped all my aluminiun plate and stuff, a couple of years ago.

To reduce the clutter.

Wise decision,

or not ?

 

Oh, just remembered I do have one peice left, infrequently used as a surface plate, even looks good, but long, not square

[YashN]

A lot of neat stuff going on in this thread.

 

On the subject of the "flat with round edges", that does give very good isolation, yes it doesn't have a particular resonance, but that is good! Go back to the thought experiment for why the flat is good. The problem is that it is like a pencil standing on its point, it's an unstable system. The slightest tilt relative to gravity and the device slides to the edge and sits there, it's better to have a gentle slope that tends to keep it centered.

 

Thanks John, and your participation makes it so too.

 

So, flatter is good but the curve is a practical necessity or compromise for realistic implementations, and we don't need a long travel distance.

 

Now, does the curvature affect the choice of ball diameter?

 

Today, as I was choosing marbles by hearing them roll on a piece of teflon-ware, I thought about having the balls slide on a teflon-coated cup. Shouldn't that help?

 

On aluminum I did a bunch of experimentation a few years ago and found that THICK aluminum has some wonderful properties, it is stiff enough that it doesn't have much in the way of bending modes. It damps compression waves enough that it does not support modes running through the material.

 

Aluminium would therefore be great for the support platform which is between the component and the ball, right?

[Daudio]

Aluminium would therefore be great for the support platform which is between the component and the ball, right?

 

I don't think it is smooth or hard enough for that job.

[YashN]

Some thoughts from last night (these things do get obsessive sometimes):

 

If we have successfully isolated our components, why don't we also isolate the listener and put his chair on the isolation platforms?

 

From Wikipedia's page on infrasound:

 

[h=3]Infrasonic 17 Hz tone experiment[/h]

On 31 May 2003, a group of UK researchers held a mass experiment where they exposed some 700 people to music laced with soft 17 Hz sine waves played at a level described as "near the edge of hearing", produced by an extra-long-stroke subwoofer mounted two-thirds of the way from the end of a seven-meter-long plastic sewer pipe. The experimental concert (entitled Infrasonic) took place in the Purcell Room over the course of two performances, each consisting of four musical pieces. Two of the pieces in each concert had 17 Hz tones played underneath. In the second concert, the pieces that were to carry a 17 Hz undertone were swapped so that test results would not focus on any specific musical piece. The participants were not told which pieces included the low-level 17 Hz near-infrasonic tone. The presence of the tone resulted in a significant number (22%) of respondents reporting anxiety, uneasiness, extreme sorrow, nervous feelings of revulsion or fear, chills down the spine, and feelings of pressure on the chest.^[38][39] In presenting the evidence to the British Association for the Advancement of Science, Professor Richard Wiseman said, "These results suggest that low frequency sound can cause people to have unusual experiences even though they cannot consciously detect infrasound.

...

 

Their research suggested that an infrasonic signal of 19 Hz might be responsible for some ghost sightings. Tandy was working late one night alone in a supposedly haunted laboratory at Warwick, when he felt very anxious and could detect a grey blob out of the corner of his eye. When Tandy turned to face the grey blob, there was nothing.

The following day, Tandy was working on his fencing foil, with the handle held in a vice. Although there was nothing touching it, the blade started to vibrate wildly. Further investigation led Tandy to discover that the extractor fan in the lab was emitting a frequency of 18.98 Hz, very close to the resonant frequency of the eye given as 18 Hz by NASA.

[YashN]

I don't think it is smooth or hard enough for that job.

 

How about Teflon-coated steel?

[Duke40]

Very cool 'man-cave', Duke40.

 

Are these the door-stops that we see in the photos? I gather you are placing some on top of your components to prevent some vibrations there?

 

Cool you mentioned the order of where you heard most benefits: I was wondering about that. I thought of doing the amp and the speakers initially, but now, I believe the source should be important too.

 

The thing is, I consider my 'source' to be a three-parter: USB external HDD, iMac and DAC. Hence, if I do the speakers, I'll probably need 3 more sets of isolators quite rapidly.

 

Anodising may well be good: I see Symposium did anodise their aluminium.

 

If that's not too much to ask: do you think the benefits for each type of component are the same, or each benefits the sound in a different way?

 

 

YashN ... Thank You !!! for the man cave compliment.

The Man Cave really is just a combo home gym with a headphone rig for music and home theatre so I do not get bored on my exercise bike. Plus it is away from the "normal" part of the house, so my experiments do not worry my GF. Anyway, it lets me experiment, doing things like that crazy DIY isolation stand & allow the rest of the house to look normal.

 

 

"Are these the door-stops that we see in the photos? I gather you are placing some on top of your components to prevent some vibrations there?"

 

Yes, the door-stops are on the very top shelf (they have the black rings around them), near my Auralic Gemini 2000 DAC/Headphone Amp.

 

They were put there mainly for load balancing of the shelves ... also the Townshend seismic springs are optimised for a certain weight (the Townshend springs can be seen in the first photo , under the 4 sheets of ALU ....and also between ALU shelves... they look a bit different from the one's you posted, they must be a later model .... as I did a lot of resonance/isolation testing & purchasing between 2005 to 2010)

 

Below is a photo ... please pardon my photography skills, I am technically challenged when it comes to taking photo's

 

They are effectively the same thing you pictured in your post.

 

... I believe these springs (in photo above) were rated for between 5 and 20 Kgs ... with it better to be approaching at least 75% of the recommended weight for them to be most effective. So the $1 door-stops were used to help balance my shelves and optimise the effectiveness of the Townshend springs.

 

 

"Cool you mentioned the order of where you heard most benefits: I was wondering about that. I thought of doing the amp and the speakers initially, but now, I believe the source should be important too."

 

Just to recap ... this is the order I found my beneficial ;

1. Speakers (stops vibrations getting into all the other electronics and effecting things like crystals).

2. DAC

3. Source (like CD player)

4. AMP

 

My hifi integrated amp is built like a tank (Pass Labs) ... maybe if I had a lighter weight amp the order may have changed ... that is ... it may have moved up in importance from 4 to 3.

 

Oh, I also notice that resonance/isolation is more critical for my speaker rig ... than my headphone rig.

 

I hear the benefits for both ... but the speaker rig it has more impact ... probably because it is the speakers that cause the most problems to other audio equipment. Barefooted on a tile over concrete slab floor .... I could actually feel the vibrations in my feet when I had music playing ... then went to touch my hifi racks (3/4 filled with fine beach sand about 50lbs worth) and could still feel the impact.

 

This got me wondering ... if I can feel the impact ... what is it doing to the crystals and DAC chips or whatever sensitive components in my audio gear. I wondered if this vibration caused extra jitter or whatnot. By the way ... just a disclaimer ... I am not an industry expert/professional like Barry Diament .... or a well respected Electronics Engineer like John Swenson ... I am just a guy who is reasonably observant .... that is I can notice the effects .... but when I type "wondering" I am just guessing what parts in the audio equipment are being affected... and why they are. Sorry for the bold type, I just wanted that to stand out, and have a personal aversion to uppercase.

 

 

"The thing is, I consider my 'source' to be a three-parter: USB external HDD, iMac and DAC. Hence, if I do the speakers, I'll probably need 3 more sets of isolators quite rapidly."

 

Do you have any moving mechanical parts in the USB external HDD or iMac ?

 

If they do not use HDD's or fans ... they may be able to exist all on the one shelf (if they use SSD's).

By the way PPA sells a ALU block that can screw onto a SSD, costs about $35 shipped I think ... so even something which does not cause mechanical vibration can benefit by using ALU (maybe it narrows the resonance band).

 

So maybe one shelf ... with an extra piece of 10mm ALU under each component ... maybe do the engraving that John Swenson mentioned (I am intrigued by that ... I may give it a go !!! Great idea).

 

 

"Anodising may well be good: I see Symposium did anodise their aluminium.

"

 

Yeah, I noticed that. Also remember an interview from 2007 (?) in HiFi + (a UK Magazine) with the designer from Arcam ... I'm paraphrasing here (plus the distance of time) ... but I remembered something like that he loved the accoustic property of ALU ... that is it "everything has a resonance band ... but ALU the band is very narrow and not in the presence region ... even narrower when you anodise it". Anyway that is the essence of what I recall (over the distance of time).

 

 

"If that's not too much to ask: do you think the benefits for each type of component are the same, or each benefits the sound in a different way?"

 

Hopefully I understand your question ... I think the most important benefits come from isolating Speakers and DAC. All equipment benefits ... after I did Speakers & DAC ... though by the time I did the source (a Marantz CD player) I was hitting diminishing returns.

 

Similar SQ type of benefits for isolating each component ... though they are cumalative (and diminish after taking care of speakers & DAC).

 

 

"Capabilities (from PF as well because the official domain expired):"

 

I wonder what is going on there ? ... I remember going to the Townshend Audio website last year and it was operational.

 

I read the PF review .... by the way I clipped the following information (and saved to Evernote) from Townshend Audio website a couple of years ago.... it is the product description for the Townshend Audio Stella Stands which I own, though it also would apply to the Seismic Pods as well.

 

As an aside I picked up my Stella Stands 2nd hand ... but the spring weights included in the stands (up to 60 kg) were not optimal for my speakers ... so I contacted Townshend Audio and asked for another 2 sets (5 to 20kg, 10 to 32 kg) ... thinking if I ever change speakers I will have the ideal weight capability for the springs. After switching the springs in the Stella Stand ... The spare springs (I had 16 in total) spent a few months in my cupboard, then I got the thought of why waste them ... why not go to the metal shop and get some ALU cut ... hence my DIY stands.

 

Anyway ... onto the Stella Stand product description ... oh, I agree with the product description, it reflects on my experience.

 

"[h=2]Product Description[/h]

Townshend Stella speaker supports feature Townshend's proprietary "Seismic-Pod" spring technology with dynamically variable gas-damping to offer unprecedented isolation for all audio components, in particular, loudspeakers. Supporting loudspeakers with an extremely soft suspension produces a vastly superior sound compared with the results when supporting with traditional spikes, cones or complicated rigid cup ‘isolators’.

 

With conventional rigid suspension, the aim is to hold the cabinet ‘still’ at audio frequencies. However, this concept does not address the effect of the transition from rigid coupling at low frequencies to cabinet/support/floor bending which occurs as the frequency rises, combined with the finite speed of sound in the cabinet.

 

Inevitably there will be a resonance set up by the mass of the cabinet bouncing against the stiff but springy ‘rigid’ suspension which will introduce a boom to the sound. Break this link and the result is magic! The speaker is now free to move minutely, but most importantly, it moves in an undistorted linear fashion with the significant cabinet mass alone reacting against the driver cones.

 

Now free from the colouration caused by the far-from-ideal rigid coupling, the improvement in fidelity is palpable. Yes, there may be a slight loss of bass ‘slam’ on the occasional heavy low note, but the improvement over the whole audio band, all the time, far outweighs this apparent slight loss. Astute listeners welcome this change and argue that the traditional overblown slam is an irritating colouration.

 

Features

 

- Reduces bass-boom to a remarkable degree, particularly with large speakers

- Produces a wider and deeper sound stage

- Greatly improves bass definition

- Delivers enhanced clarity throughout the whole frequency range with much clearer transients

- Extremely neighbour friendly

- Maintenance free (no air pumps)

- Adjustable limit stops to prevent excessive movement when disturbed

- Remarkably stable.

- Soft plastic feet which will not mark wood or stone floors, or optional carpet-piercing spikes

Eliminates:

 

- Muddiness and smearing

- Direct sound transmission into the floor

- Irritating boom caused by coupling through the floor to adjacent rooms

- Structure-borne feedback between speaker and vibration sensitive equipment

"

 

Also this review .... you may have to click on it ... or download & zoom ... so it is readable ...

 

 

 

Final thoughts ....

 

... Townshend Audio isolation gear is expensive , though it is extremely effective.

I picked mine up 2nd hand so my wallet did not suffer too much (though it was still a lot of money).

Plus I paid for extra sets of springs (as I was already an owner of the Townshend Audio Stella Stand)... not the individual Seismic Pods, so once again that was much more cost effective.

 

... I have often mentioned that these pods are "springs" ... though they also have a rubber bellows wrapped around them which improves their effectiveness.

 

... as you (and others) appear quite interested in this subject ... I highly recommend watching this 25 minute youtube video from Townshend Audio ... even if there gear does not feel right for you, I think it is educational. Max Townshend is explaining & demonstrating engineering and physics properties, in regards to isolation as it is applied to Audio. As a layman, audio hobbyist I think he does a great job.

 

[h=1]The effect of ground vibration on audio systems[/h]

 

 

By the way I do not post much ... my typing speed is abysmal.

Anyway I hope it helps

Plus it is just my experience, YMMV, and so on.

 

John

[Duke40]

A lot of neat stuff going on in this thread.

 

On aluminum I did a bunch of experimentation a few years ago and found that THICK aluminum has some wonderful properties, it is stiff enough that it doesn't have much in the way of bending modes. It damps compression waves enough that it does not support modes running through the material. It DOES support surface acoustic waves, which gives rise to the "ring like a bell" mode. But these only become a problem if you have parallel surfaces that support standing waves. It turns out you can eliminate the standing waves by "breaking up" the surface. I like to do this by taking an engraving pen and drawing some "swoopy" curves on the surface, they diffuse the surface waves thus preventing standing waves from forming.

 

A properly treated slab of aluminum gives a very faint "tink" when you hit a suspended piece. If you hear a "thunk" or "thud" it is not stiff enough and is having some bending modes. Anything high pitched but lasting more than a "tink" means you don't have the surface waves properly tamed.

 

There are actually some amazing electrical properties to thick aluminum as well. They are superb electrical AND magnetic shields. Any decent metal piece works well as an electrical shield but don't work beans as magnetic shields. Most people wind up using things like MU-metal and other specialized magnetic materials. BUT these have some bad properties for audiodom, they tend to saturate easily, limiting their effectiveness, and some of them tend to have time delay issues as well.

 

Thick aluminum has such a low electrical resistance that eddy currents are produced inside the aluminum that counteract external magnetic fields, significantly attenuating their passage through the metal. Because aluminum is not magnetic, it doesn't saturate, so the magnetic field attenuation is affective from very tiny fields to very large fields. It's effective from low frequencies (60Hz hum) up to GigaHz range.

 

These properties of aluminum are why I use thick panels to make enclosures for my electronics.

 

John S.

 

I will try the engraving pen on my ALU, sounds interesting.

 

I wondered about the effects of using ALU to reduce electrical and magnetic issues ... but I was not sure.

Thank you for clearing that up ... I find this a very interesting post.

[4est]

I think the cup and bearing materials are less about ringing, and more about surface hardness:rolling friction, stick-slip, deformation ect. Consider Barry's experience as mentioned elsewhere in this forum. He noted changes with chrome vs carbide balls and different grades of aluminum for the cups. All while things were floating on lightly inflated tubes. There just doesn't seem like enough difference between the materials in situ to account for it. The jerking of stick-slip seems like a prime candidate, but it is a guess without testing.

 

These are close to what Barry recommends (just use one per support instead of two) but made from coated steel instead of aluminum:http://www.firstimpressionmusic.com/product_p/model%20305-3.htm

Certainly because even with less than ideal materials, the process of isolation is occurring to some extent. Perfect for initial experiments compared to no isolation at all.

 

 

 

That's very cool, Daudio. As ringing, is acrylic a good material? I gather we'd need hardest and smoothest, but also something which does not ring too much, or if it does ring, then we need to dampen that by encasing it within some other material.

 

 

 

Very encouraging. How large can you make these?

[AnotherSpin]

These are close to what Barry recommends (just use one per support instead of two) but made from coated steel instead of aluminum:Model 305 /3 (Platimum)

I was trying some variations and when I was back to following Barry advices in smallest details I was getting the best sound. So, the recipe is:

- slightly inflated bicycle tube;

- thick hard plate;

- good quality aluminum bowls made on Barry measurements, placed in correct triangles, chrome steel balls of correct diameter. No top bowls!

Thats it, guys. Of course, experiments with materials/sizes/designs would theoretically yield further improvement, but, given the costs of machinist labor + materials I stick to Barry ideas.

[Daudio]

How about Teflon-coated steel?

 

How about polished steel, as in those camping mirrors that John S. recommended ?

 

Aluminium doesn't polish well, probably the softness, but anodizing does create a very nice surface on alu, but not quite as good as a polished hard metal, IMHO.

 

There is something about a Teflon coating that just doesn't sit right with me for this application, but I can't put my finger on a rational explanation.

[4est]

Because the rolling friction is too high using teflon.

How about polished steel, as in those camping mirrors that John S. recommended ?

 

Aluminium doesn't polish well, probably the softness, but anodizing does create a very nice surface on alu, but not quite as good as a polished hard metal, IMHO.

 

There is something about a Teflon coating that just doesn't sit right with me for this application, but I can't put my finger on a rational explanation.

[Daudio]

- good quality aluminum bowls made on Barry measurements,

 

Can you give us an idea of how much your custom bowls cost per set ? And about how many sets you got to get that price ?

 

TIA

[AnotherSpin]

Can you give us an idea of how much your custom bowls cost per set ? And about how many sets you got to get that price ?

 

TIA

 

I am in Ukraine. Last year I paid equivalent of less than $100 for two dozen bowls for material+labour. Aluminum used was similar to 6061 (other codes here).

[JohnSwenson]

In my listening room my speakers are isolated (in the horizontal plane) by suspending them from the ceiling by bowstrings. (special high strength string used to string high performance bows). The string is about 6 feet long, this gives a very low frequency resonance which is very effective at isolating the speakers from everything else.

 

John S.

[YashN]

They are effectively the same thing you pictured in your post.

 

... I believe these springs (in photo above) were rated for between 5 and 20 Kgs

 

Townshend Stella speaker supports feature Townshend's proprietary "Seismic-Pod" spring technology with dynamically variable gas-damping to offer unprecedented isolation for all audio components, in particular, loudspeakers.

 

This is very interesting to me, because Townshend seems to have moved away from the pneumatic isolation to the Spring + Rubber combination, together with that 'dynamically variable gas-damping' in the stella, so he does add damping to the arrangement as well.

 

Do you have any moving mechanical parts in the USB external HDD or iMac ?

 

Both are HDDs => yes, rotating platter construction.

 

By the way PPA sells a ALU block that can screw onto a SSD, costs about $35 shipped I think ... so even something which does not cause mechanical vibration can benefit by using ALU (maybe it narrows the resonance band).

 

Interesting, may have to check it out.

 

Also remember an interview from 2007 (?) in HiFi + (a UK Magazine) with the designer from Arcam ... I'm paraphrasing here (plus the distance of time) ... but I remembered something like that he loved the accoustic property of ALU ... that is it "everything has a resonance band ... but ALU the band is very narrow and not in the presence region ... even narrower when you anodise it".

 

Thanks for that, always happy to learn more about our music chain and mechanism and optimisations every day. BTW, I have family and old friend in Oz.

 

Similar SQ type of benefits for isolating each component ... though they are cumalative (and diminish after taking care of speakers & DAC).

 

Yes, qualifications about each component's isolation was what I was after.

 

I wonder what is going on there ? ... I remember going to the Townshend Audio website last year and it was operational.

 

Not sure, I hope it's just he forgot to renew it rather than he doesn't have the means.

 

Anyway ... onto the Stella Stand product description

 

Thanks a lot for that and for the video, re-embedded here for convenience, much appreciated.

 

[YashN]

I don't think it matters much whether the curved cup is on the top, or bottom. You can experiment, of course.

 

It would be interesting to listen for differences and if there are, understand why. If the cups are mounted component-side, I guess we'd want the component itself to be tightly coupled to that cup?