Ball bearings or teflon pads ?
Posted by: DIL on 05 September 2001
I have followed the recent QS etc threads and a couple of times the use of ball bearings and nuts (as an intermediate decoupling between shelves and equipment ?) has been mentioned. If I interpret things correctly, this 'mod' was regarded as improving sound quality and therefore worth looking at if high end / good out of the box stands are not an option (Family and monthy budget and all that...).
I have tried to search the forum but drawn a blank. Can anyone post a link to the thread(s) in question, or provide any specific details.
As an aside, has anyone tried decoupling equipment from stands using teflon pads. My thinking here is that the equipment would be free(ish) to move due to teflon's low coefficient of friction. Any 'sticktion' (higher coefficients of friction at zero relative speed.) effects would help to dissipate energy..... Maybe 
/david
I am curious now about the effect of Nordost Pulsar Points, as they must have the opposite effect.
It's always a nice day for it, have a good one 
Steve
quote:
My suggestion of Teflon pads (actually two, one attatched to the stand, and the other attatched to the shelf making the latter free to slide.) was simply checking if anyone had considered or tried out this as a concept.
David
No, I've never thought of trying Teflon pads. Don't even know where I'd get them, and to be honest, I've never even heard of them. 
Sounds interesting though. I'm currently looking around for another source of plywood for another support idea and you've given me something else to consider.
quote:
What are forum members views as to what is happening in a support that works ?
I don't think you'll get much joy with this one. I've been reading threads about supports on the forum for ages. I don't think we can agree on which supports work. Even when they appear to work we can't agree on why they work. Even if most people agreed something worked someone else wouldn't agree. If we found something we all thought worked, and we knew why it worked, someone would come up with something that works better that what we'd already agreed worked ok in the first place. Suddenly, the one we'd all agreed worked wouldn't work at all anymore, but not everyone would agree on that either. 
Of course, whether something works or not is subject to the room it's in, the gear that's on it and the ears that are listening to it. 
Do some experimenting and come back with your findings. I'll be interested and I'm sure lots of other people will be too. I may even try your idea out for myself.
Brian
[This message was edited by BD on WEDNESDAY 05 September 2001 at 19:17.]
David:
quote:
What are forum members views as to what is happening in a support that works ?
Here's my rough idea of what an ideal support should do:
1) Block the transfer of mechanical energy from the environment to the equipment.
2) Facilitate the transfer of mechanical energy emanating from the equipment away from the equipment.
3) Nothing else.
Unfortunately, this isn't a particularly useful prescription in the real world.
quote:
What is actually happening - energy dissipation ?
Mechanical energy from the environment and the equipment [the latter either generated within the equipement or as a reaction to energy arriving at the equipement via the stand] is present in the stand.
Essentially, four things can happen to the mechanical energy in the stand and equipment:
1) It can be damped internally and dissipated as heat.
2) It can flow to earth [and a little bit into the air as well].
3) It can be transformed into other forms of sound/vibration. E.g. a coherent sound wave at a given frequency can be converted into incoherent waves of many different frequencies.
4) It can be stored somewhere within the system and later returned.
(These aren't entirely mutually exclusive but they suit my understanding of how stands work).
Delayed low-energy resonance V rapid high-energy resonace:
Anyone who has ever tried a sorbathane or rubber mat in place of the felt mat (or no mat or whatever) on their high quality turntable will probably be able to report that the sound is much cleaner but instruments are more difficult to distinguish from each other, the rhythm is messed up a little, and it all sounds rather boring. In my opinion this happens because, although a lot of the vibrational/sound energy is dissipated as heat by the Sorbathane, reducing the amount of energy flowing between platter and record [making for a cleaner, "blacker" sound] the energy that isn't dissipated is stored for a while only to be returned to the record in coherent enough a form to manifest itself as low energy but relatively long-lasting resonance. This affects the sound in an audible way - altering the attack envelope of notes, for example.
By contrast, a felt mat allows more energy flow in both directions, and allows much louder resonant peaks from the platter to get through to the record. These peaks, however, occur in a much shorter space of time - so short that they cause little harm to a note's attack.
[I have to stop here - splitting headache - more tomorrow, perhaps 
]
--Jeremy
It's always a nice day for it, have a good one
Steve
), the only thing there which makes me wonder is the importance of isolation vs. the importance of dissipation. Most commercially available stands pander to the press-endorsed belief that "isolation" is what one is aiming at. It's fairly easy to see how this has arisen, since originally, turntables with suspension generally sounded better than those without, whilst being more expensive. Although higher prices also meant better bearings, etc., it seemed obvious that the presence of suspension was contributing to the percieved better music. Putting the assembly on a light & rigid skeletal structure with floor spikes helped further. Immediate logical leap: "Isolation is good, spikes help isolate". the idea that music is coming across the room, getting into the turntable and messing things up through continuous low-level feedback is an easy one to snatch at, and definitely a factor to consider.
I think, however (and remember my disclaimer in my first para.!) that it may be, if not a red herring, then certainly less important than conventional wisdom would suggest, as the benefits of a good support are still evident in situations where (a) the speakers are in a different room, or (b) listening is via headphones. Pre-amps seem to be the only common exception to this, and it may well be that for them, isolation is primary. In a way, this makes sense.
My point is that dissipation of (or otherwise allowing for) vibrational ernergy apparently emanating from the item supported does seem to be pretty vital. When you think about it, practically everything has a moving part capable of having an effect on the other circuitry in the box, whether this is a transformer or a motor, or both. If your chosen support incorporates both an easily-excited element(s) and some sort of relatively efficient interface to allow transfer, this effect will surely be reduced. How the energy thus tranferred is then handled post-transfer, is of course, yet another can of worms.
I think that the "sound" of a stand in a given room with a given system is very strongly affected by the stand designer's view of the relative importance of isolation and dissipation. Isolation seems to be all about combinations of mass and spikes, with the better ones paying a great deal of attention to resonances (surely this is the rationale behind the QS "wobbly" approach, with concave edges being a big part of it). Hutter just seem to rely on simplicity, and very serious quality control and consistency to even everything out. The most emotionally vivid system I've ever heard was on Hutter. Mana and Fraim seem pretty similar in terms of their mechanics, with a lot of attention paid to dissipation; Fraim's one-end-fixed aluminium "vibe tubes" appearing to serve the same purpose as Mana's horizontal rails... at a price both financially and in terms of its enormous footprint.
Frustrating thing is, the research required to build a "better" support has probably already been done.
Best;
Mark
(an imperfect
forum environment is
better than none)