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There is a portion of an article @ positive-feedback that talks to mass loading your audio rack for isolation and tuning. This is a kind of followup to the 'isolation' posts below.
~ Pat O'Malley
Follow Ups:
The critical line in the article for me is :" .. here's a good one. If you have an unused shelf, try placing the weight there. I put an idle 20 lb AC conditioner on an empty TAOC shelf. This worked well and left my components' voices alone."
Which is to say that quite often loading the shelf , the rack , or whatever platform you're using may often pay dividends that loading an individual component may not.
And you may want to consider that loading on some other plane from the component.
And as Fret notes below, component-loading, often as not, sounds like just that : a loaded-down component.But often enough, not so the support platform. Very often the platform is built to some kind of perceived-value 'overkill' standards that means they've got huge headroom for weight, and don't really begin to do the job till they're correctly loaded, and anchored down.
If I recall correctly, the industrial versions of the Vibraplane even cite minimum loads for correct operation as well as max loads.
As User510 notes, even a set of welded steel tubes as a wallshelf is extremely over-rated for something the weight of a Linn Lp12, and won't be put to best use by underwhelming it in that way. (And until he granite-loaded his wallshelf, he was under-utilizing it....)But note-- no one's talking about mass-loading a Teres. We're talking about mass-loading racks and supports for devices like the Teres to perform their best on top of.....
This is an endless topic, and straddles an endless stretch of grey area, but there is one guideline to go by-- too much is way too much . Over-doing the mass-loading thing kills everything the music has to offer, so keep an ear out for anything that seems to "firm up" but also " deadens " as it firms up. That's the red flag.
*
groove
At one point, a few years back, I had weld-fabbed a wall support out of square steel tubing for my turntable, the Teres. To cut down on the natural "ringing" of the hollow steel tubes I injected polyurethane foam into the tubes throughout.The steel structure was very rigid and strong. It was easily capable of accepting any realistic load I might place upon the rack....itself. However I was a little leery of placing too much weight on the structure because of unknowns regarding the 2x4 studs it was lag-bolted into. A total of 6 steel lag bolts secured the rack directly into the fir studs.
Being cautious I first used a multi-layered MDF shelf (about 40 lbs) between the Teres and the rack. What I noticed right away was a --tremendous surface noise between tracks-- when playing the Teres. To reduce this I placed an alternate material "pad" between the supporting threaded studs of the rack and the mdf. This reduced the noise considerably.
Later, after I became confident that the lag bolts weren't going to tear loose from the load bearing studs they were anchored into, I replaced the mdf shelf with a granite shelf measuring 18x18x3 inches. The granite weighed something over 100 lbs by itself. The steel rack easily supported the granite without evidence of strain. One of the things I noted after placing the granite shelf was that the surface noise (hash) went away completely. Also, low frequencies became more prominent in the Teres' delivery. It was altogether a more "slammy" sounding turntable while standing upon the granite. At a later point I placed one of Ken Lyon's "Neuance Shelves" flatly over the granite and allowed the bdr cone feet of the teres to stand on it. This was the best sounding situation yet. Low frequency weight and bass slam were not diminished but the mids and highs became more natural, extended and detailed.
Later, in a conversation with Ken, he explained that the difference I heard when implementing the granite, was a result of placing a load burden on the supporting fir stud structure..... That this in fact altered the natural resonant frequency of the structure and effectively filtered out the "noise" that existed in the load bearing 2x4 structure of my building. Btw, I'm up on the third floor of an apt. building constructed in the early 1990's. It is built light, flexy and with the least expensive combination of wood product materials.
Disclaimer: No affiliation with Ken or his firm "Greater Ranges".
That said here's a little conjecture:
The Teres is a TT known to appreciate mass loaded supporting structures. There is plenty of anecdotal evidence to support that, just talk to any of the owners.But what would happen if you placed a turntable noted for sounding its best upon the "light-rigid" style of support? Example, LP12, or any of the Rega turntables. And possibly the suspended Thorens TD150/14x/16x series and of course the ARs. I would suggest the following: Arrange to have a massive stone floor upon which you place your light and rigid floor-standing support rack. Then you should have the best of both worlds; a placid, unmoving support but with the resonant interplay that seems to work so well between the light rack and turntable. Just a thought.
-Steve
I have a modded NAD on a two layer HDF + paving slab of granite. There is a thick rag between the granite and the HDF to dampen any ringing. There is also cement still adhering to the granite that helps with that, I think. There are two other slabs on the other two shelves. And I am using vibrapod feet/cones. The table is situated between two big ass Paradigms.The Paradigms do not have any energy on the outside of the speaker. Holding your hand on them when blasting and there is no vibration.
I once dropped the record weight I use on the rack shelf while a record was playing and nada. No skip, no noise. no nothing. AND the sound is lively. the sound is not "sucked away" or anything like that.
I have no idea what works in any other system. While not being as exact in craftsmanship as you are(kudos amigo), I only know that adding the granite slab for my NAD helped to do the exact same thing you desribe for your Teres.
All evidence is anecdotal isn't it? ;-)
Have you tried the Neuance Shelf under the Thorens?
Yes I'm not surprised. The mass loading likely stabilized your floor in the immediate area of your TT. So far it works like a charm for me in my environment."Have you tried the Neuance Shelf under the Thorens?"
No I haven't because the Neuance is rated to support a max weight of 65 lbs. I'd be exceeding that with the Slate plinth/td124. I really would not want to destroy that nice Neuance. Since you bring it up, I should probably put it to use under some other component, perhaps the Classe' integrated amp...! I'll try that.
cheers.
-Steve
user510's system
Good article, and you helped answer a question to my post below. Not that mass loading is necessarly my answer, but experimenting IS.Guess I was looking for the easy way out, since I'd rather be listening to music than fooling with the system. But you gotta do what you gotta do.
Thanks again.
i think we return back to the fact that no single solution works in all cases.some theorize that while mass loading *can* be a great thing (particular as described in the article -- mass loading vs. mass damping, to use their parlance), it can also be less than ideal. for instance, a great mass is tougher to get moving, but once it is moving it is tougher to stop. the resonant frequency changes.
others believe that light+rigid is a good design such that any vibrations are quickly dissipated.
is one better? maybe.
i think the answer is 'it depends'.
Many think of mass loading and damping as being the same thing. Adding damping to a rack is a good thing. But just adding mass generally works poorly. A granite slab for example is very resonant. Sure it's heavy but it provides no damping, if anything it will add it's own resonance to the system. On the other hand sand and lead shot are really good at dissipating vibrational energy. It's the loose particles rubbing against each other that convert vibrational energy into heat. Both add mass but it's not the mass that is beneficial, it's the damping.
If your stereo system is measuring a groove dimension, then it has moving parts working against moving grooves.Mass loading helps eliminate distortion due to resonance.
This is why all high end measuring scales are placed on high mass platforms.
Otherwise they cannot measure to 1/10,000 accurately. By the way your cartridge is asked to measure to 1/20,000 every time you play it.
"Mass loading helps eliminate distortion due to resonance."That's odd. In my experience, mass-loading is frequently the cause of distorted musical timing due to its nasty tendency to "slowly" release stored resonant energy back into the system with predictable results; smeared note attack and truncated decay, confused rhythms, and a generally lifeless musical presentation.
Mass-loading can certainly be an effective tool when used judiciously as part of a carefully engineered system - the Avid Acutus is a good example - but baldly claiming that it "always works" is the same kind of tubesforever ignorant bullshit that's been stinking up the VA archives since you first got your grubby mitts on mommy's computer.
"This is why all high end measuring scales are placed on high mass platforms."
Very astute, Professor, except that "high end measuring scales" are static devices and aren't required to reproduce a musical continuum of notes and beats with their subtle pitch and timing relationships more or less intact.
"Very astute, Professor, except that "high end measuring scales" are static devices and aren't required to reproduce a musical continuum of notes and beats with their subtle pitch and timing relationships more or less intact."Actually this is incorrect... both cytography and some confocal microscopy experiments are designed to monitor changes in dynamic samples. The pitch and timing relationships that are required for music are trivial compared to the atomic resolution scanning limits that these instruments are capable of.
I stand corrected on the static observation.OTOH, I'd be willing to bet that if the dynamic sample being measured was constantly firing off the sound of kick drums and low bass notes, and those sounds were being amplified and reproduced back into the measuring environment, all that low resonant frequency mass damping might prove unsuitable, especially if reproducing the timing and shaping of those notes was absolutely critical.
The interaction of a turntable and its environment is kind of like a continuous shock wave; the thing being measured is the source of the vibration interfering with the measurement.
The resonant frequencies of the components and their supports all effect the timing of the energy being bounced back and forth throughout the system, and that has a dramatic effect on the subtle temporal relationships between the attack, sustain, and decay components of the notes. Or so my ears tell me.
But by mass loading I do not necessarily mean to say that the turntable needs to be massive.Rather the stand and the foundation for the stand should exhibit high mass.
With some buildings, as has been pointed out to me, a wall mount light but stiff shelf will be the answer.
I am simply stating the obvious. If you want to hear everything in the groove, the platform for the turntable must be immobile. High mass always works even with a light and stiff shelf....think about it. The mass is coming from the structure that supports the shelf.
I appreciate your point of view. But if the base is not immobile, you are leaving music on the table (so to speak).
"Rather the stand and the foundation for the stand should exhibit high mass."Tell that to Mana, Neuance, Symposium, Zoethecus, and Finite Elemente, etc. These companies all build rigid low-to-medium mass supports that sound great, but more importantly, they help your gear maintain a tight grip on the music's PRaT.
I've heard an LP12, several Regas, two Technics, a Spacedeck, a Roksan, a Scout, a crappy suspended Basis, an Avid, a Scheu, and a Michell (my bell) in what was essentially my current system. The only one that sounded better with a massive support - in this case, a thick Mapleshade slab - was the Scheu.
The latter was the forerunner of Teres and its spin-offs and has a massive 4" thick plastic platter. It's an insipid, rhythmically awkward 'table that couldn't out-pace anything short of a Sota with a good headwind behind it, regardless of its support.
In every other case, each massive support I tried - a sandbox, a granite slab, the aforementioned thick maple; all on a massive sand-filled steel rack and/or my Zoethecus frame - sucked the drive and energy out of the music and made the rhythms sound confused and tentative. Granite tended to sound lumpy, edgy, and slow; sand was lifeless, dull and dry, and thick maple was warm, bloated, and lackluster.
There were a few isolated sonic or spatial improvements here and there, but only the Jazz at the Pawnshop crowd cares about that when the music's timing and energy are screwed-up.
So much for "always" when it comes to crude mass-loading. In my experience so far, a well engineered light, rigid support is the ticket if you want to bring the music back alive . A massive support is probably mandatory with a really massive non-suspended turntable, but I've never heard one of those that wasn't sleep-inducing, and as Dylan sez "when ya got nuthin, ya got nuthin to lose."
...the earth is 'high mass' but moving!"If you want to hear everything in the groove, the platform for the turntable must be immobile. High mass always works even with a light and stiff shelf....think about it. The mass is coming from the structure that supports the shelf."
the earth supports my floor, which supports my floor-mounted rack...and the earth also supports my wall, which supports my wall-mounted shelf.
i guess i'm OK then -- or not, since the earth is not immobile.
what's an analog-lover to do? :)
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