To spike or not to spike, that, is the question.

….my rack, that is.

I know this is covered repeatedly yet I’ve seen nothing pertinent to it in hollow floor applications. My current boat anchor, er, Sound Anchor rack, poses me an issue in this area of resonance control… or just something to do.

HOWEVER there seems a decision needs be made on either coupling, or de-coupling presently. Given it’s size and weight, I’d sure not want to be dancing it onto and or off of different footer gizmos over and over again.

I would like to know what experiences anyone has in this regard... and with what manufacturers' spikes or what-not.

My floor is hollow... carpet & pad over 5/8 flooring, on 16 OC 2x10 joists.

I'm thinking to add a piece, or two, of plywood (1/2 - 1 inch) underneath the rack and on top of the carpeting & pad, right off. Thus adding foundation & support.... as the weight will be near +/- 425 lbs with the components aboard.

How thick to go doesn’t seem as much the issue as does perhaps, the overall width and length though… as increasing the area coverd should help spred the disbursement of the weight atop it.

Rack exterior dims are roughly, 24 x 18. I was thinking to add two - three inches all around and use no less than ½ inch 5 layer ply.

So if the above doesn’t seem a bad idea, the couple or de-couple item is all that is undecided.

Thanks much, as I do sincerely appreciate the input.
you have a few issues going on here.

a suspended wood floor as you describe has two main challenges; it will transfer footfalls to your gear and also transfer the acoustic feedback from your speakers to the rack.

with a suspended wood floor the best solution is to brace the floor below under the speakers and rack if possible. if it is a crawl space or basement then ideally you would install some beams onto concrete floor or pads. if this is possible there are specific methods to use.

if it is not possible to brace the floor then the next best approach would be to dampen the floor under the rack and speakers to reduce the level of energy which gets transfered from the speakers to the floor and the floor to the rack. this can be done by 'mass loading' the floor with a tray of sand......the sand will absorb much of the resonance from the floor. you would want to spike the 'sandbox' to the floor thru the carpet to firmly attach it to the floor.....or it will be 'squishy' and not really dampen.

then use some sort of de-coupling footer (which decouples in the verticle plane) on the platform resting on the sand. there are a number of these..... still points, Apex footers....etc. this approach gives you alternate layers of mass and decoupling. the level of benefit will depend on how much floor movment you have. it will help with acoustic resonance but likley will not do much for footfalls.

an alternative to all this would be getting a Grand Prix rack system with Apex footers. it is designed to deal with suspended wood floors by using different layers of decoupling. the shelves use special sorbothane pads to dampen resonance; these pads are tuned to your specific gear. the legs of the Grand Prix rack actually are flexible and decouple; and finally the Apex footers absorb quite a bit of resonance. in addition to all this decoupling; the legs can be filled with sand or lead shot to tune the rack to the specific floor conditions.

it's not cheap but short of extemely expensive active isolation the Grand Prix is the very best rack solution for suspended wood floors.

Thanks much, I appreciate it greatly.

Getting up underneath the floor and adding cross braces from one joist to another likely won't happen. At best might be some more foundational supports to the closest placements of the spkrs & rack... maybe.

Footfalls aren't an issue. I'm alone. Neither are acoustic/air vibrations as the components reside in a closed off, and seperate room from the speaker/sub, and me when listening.

Sand box, huh? how big/deep should it be for this Sound Anchor rack which I think weighs in around 180 dry, and about 440lbs. (+/-) filled with devices & wires???

These 'sand boxes' don't subtract from the harmonics in any shape or form, do they? (dulling transients, occluding inner detail, etc)

A GP rack or any other rack for that matter, just ain't happening. Period.

Apex footers? Maybe. If they will attach to the SA racks threaded opening and don't cost a great deal.

Couple the sand box to the existing flooring, and de-couple the rack resting atop the box, from it?

Same way for speakers? They weigh in at 90lbs ea give or take a bit.

I'll assume you have done this and realized good results?

Thanks again for the help here.
Blindjim, a wood suspended floor is perhaps the most common floor in North American homes and should not be considered a bad thing unless the house is very old and actually has a pretty serious bounce to it. Much older homes with fewer floor joists can indeed present a multitude of problems but the vast majority of us simply do not have such homes.

Here are a few tidbits to help make a more educated decision and yes I’m fully aware that some of these will contradict conventional wisdom:

O There are two (actually 3) resonance energy management methodologies; isolation and dampening (aka de-coupling), resonance energy transfer (aka coupling), and a combination of 1 and 2.

O There are 3 sources of resonance energy, air-borne, floor-borne, and internally generated ie motors, power supplies, etc. and one of these sources induces far, far more harm than the other two.

O If a mfg’er or enthusiast is not able to discern or incorrectly chooses which of these sources induces the most sonic harm, then one can experience little if any of the sonic benefits of proper vibration management. If for no other reason than the methodologies for treating the different sources is almost diametrically opposed. And typically if some benefits are observed it's in spite of rather than because of.

O Any scientist worth his weight will tell you that it is against the laws of physics (it’s physically impossible) to isolate anything from vibration. The entire world is literally vibrating. When a mfg’er claims his products isolate from vibration or even leans in that direction, he’s giving clear indication that he knows not what he speaketh and you can bet dollars to doughnuts his products will fall far short of the mark.

O One can dampen vibration and thus change the characteristics of sound. With a playback system this is a crapshoot at best and sonically detrimental at worst. For example, what if you were to dampen the body of a violin or horn or acoustic guitar or drum kit? Sure, musicians may do this to their instruments on occasion to produce a certain effect but we’re talking playback systems here. And if one attempts to dampen a playback system they are dampening/altering all musical information across entire frequency spectrums top to bottom, not just a single instrument for special effect.

O Resonance energy or vibrations are captured in a moment in time but they can only dissipate over a period of time. A reverb actually. Consider the results of striking a tuning fork. If you strike the tuning fork and then hold it close to your ear, you will hear it resonate and ring for perhaps 60-90 seconds or longer.

O Resonance energy behaves exactly like electricity. It is always seeking ground. Hence, the little spikes, cones, points, etc. and racking systems function to act as mechanical conduits transferring resonance energy from the component chassis to rack, to the sub-flooring system, and eventually to ground.

O The goal of proper vibration mgmt is to create an expedited path to ground.

O Kitty litter, tennis balls, sorbathane, sand, hockey pucks, air-filled inner-tubes, etc. all have their place in life but should have no place in high-end audio. Even perceived benefits are simply no match for the real thing.

O Any break in the resonance energy exit path and the vibrations captured in a moment in time have no choice but to remain trapped and dissipate over a period of time wherever they confined. The difference is like traveling the 405 fwy in Los Angeles at 5 pm rush hour v. 3:30 am. The vibrations are still there, but they flow freely away from the components.

O When vibration management is done correctly and one’s system is of good modest quality or better, the probabilities are extremely high that you will not hear another system exhibit such detail, transparency, and musicality and thus bring you far closer to the live event than you or the industry experts ever thought possible in a playback system. In fact, I call it THE final frontier in high-end audio.

O if all the above is true then, as one might imagine, coupling becomes an all or nothing commitment. Just one break, inferior spike or rack, or any other compromise in the mechanical conduit path and any potential for sonic benefits by that component or system drops to almost zero.

O Despite the overwhelming and almost unanimous historic popularity of de-coupling, there is really only one proper methodology for vibration mgmt and that is coupling. Hearing the results of a system properly employing the coupling methodology for 60 seconds should demonstrate that point. However, finding a system properly employing the coupling methodology and to its possibly fullest potential is impossible. Well, almost. :)

So to answer your question whether to spike, cone, or point or not, the answer is a resounding Absotively, Posilutely.

Disclosure: I dabble with designing and mfg’ing performance-oriented racking systems.

stehno... thanks much.

If I read ya right... then ONLY coupling works best? W8ith componnets too? hmmmm.

My concern remains the (IMO) inordinate weight being thrust onto about 3.5 sq ft. of flooring... so my choice is to aid or increase that surface area to 4sq ft by adding the one inch of plywood resting atop the carpeting.

THEN spike to that material. I get it that the added foundation supportive measures actually will become something of a barrier to drainage right off, but as things settle in I believe the added footprint will be helpful, or that is the aim.

Either some blunt spikes are now needed or the use of 'coins' under the cones is necessary. the sheer weight of the filled rack will start drilling it's way downward.

My previous shelving unit had no mass. None. As I added to it's weight things began to improve some... yet I chose to contain rather than drain with that one.

We'll see about doing the opposite now with this sky scraper unit.
Blindjim, yes, in my experience there is only one correct way to control or manage resonance energy.

Based on the few picture you have of your system it appears that your home was built in the late 80s or early 90s and it also would seem that your sub-flooring system is pert-near identical to perhaps 85% of the rest of North America.

In other words, you should have no concerns whatsover about weight concentration in a small area. Pounds per square inch it should not much different than a women wearing high-heels.

You should keep in mind the whole concept of creating a mechanical conduit with no breaks. Your carpeting and pad create a disconnect so you want your spikes, cones, or points to break through that to make contact with the sub-flooring system.

If you install a piece of plywood for support, your sub-flooring system does not benefit because your sub-flooring system probably already consists of 3/4" plywood but more importantly you would be creating another layer of disconnect between the plywood sheet, the carpet, and carpet pad.

Again, if you install blunt points, coins, or coupling disks you will create yet another laywer of disconnect. We're talking sub-flooring underneath your carpet and pad. Where nobody will ever see the tiny dimples created.

As you can see coupling is rather straight forward and really is an all or nothing endeavor. but more importantly, it is replacing an old outdated mindset of a methodology that never really worked except on paper with a new mindset for a methodology that does work.


Thanks Stehno

Just as a FYI… the homes’ design may be a vintage one but it was constructed in Jan 2004…. Move in was Feb 2004.

Flooring is 5/8 tongue in groove over 16” OC joists. All the trusses and studs are also 16” OC.

The hasty posted pics are not where the gear resides. There was simply more room to shoot. It all rests on the other side of that wall in my office. Only myself and the transducers & sub reside in that room.

I get what you are saying. Absolutely. My concern is the 5/8 flooring being drilled into by four pointy spikes with 400+ lbs behind them.

Past that fact, I’m good.

So then, this idea comes to mind, “What sort/type of spike would you recommend for that amount of weight & flooring that you have used with some success?”

The “WHATEVER SPIKES” need to be 3/8 in 16 TPI, as that is the application here..

One last note… each level of the Sound Anchors rack has on the front and rear cross members, two thin but compliant discs/pads about the size of a quarter or so… thus four pads are ‘buffering’ – supporting, each component shelf.

won’t these “pads’ hamper that drainage notion some or altogether?