I don’t think they wobble at audio frequencies JimDog and I always thought the wobble was by design. I doubt I would hear any difference if I tightened everything up tbh. I am not much of a tweaker really.
Yes, the rack is not likely to wobble as fast as, say, a speaker driver (or a high res sampling frequency)!
But a Quadraspire rack (and any other rack I can imagine) will wobble in response to movement of the air, the ground, and the components on it.
If a rack wobbles a long way back and forth, or starts wobbling quite fast, I would expect that to shake the components and that has the potential to mess up the sound.
That’s why I have 7 Xanthe-designed vibration isolation glass shelves under my Nsaim boxes.
This goes in the category of small changes that may not each make a clearly audible improvement to SQ (but which might add up with other changes to make the system sound better).
I am interested in the practice and theory of whether a tighter or looser Quadraspire rack is favourable.
Generally, I screw the legs to each shelf pretty tight, to form a stable level platform, but not as tight as I can make it.
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I might give this isolation method a crack. What size balls do we need guys?
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It’s not critical:
Silicon nitride balls around 5mm to 6mm, steel ball bearings to make the depressions about 8 to 13mm.
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Great, Thankyou.
Any particular place to get the brass discs? I had a look on eBay but couldn’t find any that fit the description.
Hi Mark
It’s mentioned in here:
Jim
I eventually found a seller on Etsy. Search for brass discs. They came in packs of five.
Silicon nitride balls were easier to find.
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Make a small dent in the centre.
Place the disc on a strong level surface.
Place a steel ball bearing in the small dent.
Drop a hard heavy object (e.g. a 2kg hammer) onto the ball bearing from a consistent height…
Voilà… dent large enough to accommodate the nitride ball.
The version I used are also plumbing stop-ends, but they have a wall around them.
In the final version there is also a LOT more clearance between the black constraining part and the nitride ball.
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I drilled a through hole in the centre 6mm dia? Then seated the steel BB into it before smacking it with a 20oz steel hammer. No overly scientific I know, but enough to create a chamfer ( radius really) and locally work harden the brass end stop. Then locate the ceramic BB into it.
Hello Roberto
Wouldn’t in theory the ceramic ball have contact at a linear point around the circumference rather than the single point contact of a smaller diameter ball to a larger diameter depression?
It may not make much/ any difference in real terms
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That will give quite a different (and less efficient) energy distribution than having the ball sit in a depression in the brass with ‘single point’ contact.
It is likely to make a significant difference, but exactly how much difference will depend on the properties of the supporting rack and on environmental factors such as the directionality and frequency distribution of prominent vibrations.
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I wonder whether the flatness of the underside is a key factor.
If the impact of the dent making blow warps the underside and that’s not fully corrected by sanding the underside, the whole brass cup may not stand cleanly and firmly on the rack shelf.
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Precisely why I ground the underside flat again using wet or dry paper supported on a sheet of glass.
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Jim, the base will need to be sanded flat as it get deformed slightly, but being a soft metal its very easy to make flat
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Do speaker spikes couple the speaker to the floor or decouple the speaker from it? My speakers sit on carpet, underlay and a suspended wooden floor. They came with spikes and metal/rubber feet. The latter sound better to me, although it’s hard to define why.
There are some relevant posts about this from about post 67 onwards.
Cheers, Ian
Presumably the idea is to make a dent to stabilise the nitride ball providing a single point contact whilst stopping it rolling around?
Also the nitride ball needs to be tall enough to be clear of the side walls?
Are they just standard plumbing end stops?
Apologies for a lot of questions
Yes, yes, and yes.
The same principle, but more sophisticated:
-Floating type vibration isolator by radial symmetry silicone ring structure.
-Adjustable tension setting by the number of rings.
-Double vibration isolation design by silicone rings and 3-point support ceramic balls
-Radial symmetry ring design absorbs, diffuses and dissipates all kinds of vibrations more effectively.
-Precisely machined duralumin body and hard anodized top plate.
-The number of silicone ring layers: Small - 4 layers (48 rings), Large - 6 layers (72 rings)
-Height adjustment range: 20mm(0.79 inch).
-Size(DiameterHeight): Small - 6040 mm(2.351.57 inch), Large - 7947 mm(3.11*1.85 inch)