[PaulFolbrecht]

So, like most audiophiles, I've got my speakers spiked to my floor and my gear rack and amp stands as well.  I have 40lb, 2"-this acrylic amp stands by Custom Isolation on which sit my Consonance Cyber 845 monoblocks, each of which ways around 55lb.

A couple weeks ago, I noticed a buzz coming from my system on deep bass notes that required immediately attention.  Lo, and behold, the top of the tranny cover was vibrating.  The spiked GMA C3 speaker was about 1' from the amp stand. 

Thinking about it, was hardly surprising that this would happen.  Despite the stand/amp combo weighing almost 100lb, it's spiked to the floor, and so is the 130lb speaker next to it.  Why *wouldn't* those deep bass notes find their way to the amp??

It turns out I could fix this problem by moving the amp stand about 6" farther away, which I did.  However, just because the amp's tranny case doesn't actually resonate anymore doesn't mean the amp and all it's components aren't being subjected to serious vibration!  I think certainly that a lot of the higher freq waves are damped, but not so much the bass freqs.

I think the solution here, or part of it at least, is to decouple either my speakers or my gear from the floor.  Which one is not yet decided, but I believe probably the speakers' spikes should go.  I know this will result in a decrease in bass extension - it will likely loosen up the bass.

Anyway, I thought this would be a very good topic for discussion in general, concerning spiking, mass-vs-isolation vibration control, etc.  I'm familiar with the various isolation strategies and perhaps another layer under my amps' feet (they have 1/2" rubber feet, on the 2" of acrylic) is a good idea as well.  I plan on experimenting in this area in the coming weeks.

Thoughts welcome!

Paul

[zybar]

Paul,

You wrote that removing the speaker spikes would result in a decrease in bass extension - it will likely loosen up the bass.

So why not decouple the gear and not start out by negatively impacting your system?

George

[DSK]

Paul, this is a huge and very subjective topic that has generated a great deal of argument over the years. Search on Audio Asylum and you'll find stacks of discussion on this in the past.

If you want to quickly and cheaply experiment with decoupling your components and/or speakers from the floor, try a quick and dirty constrained layer platform. Just take two slabs of 0.75" plywood (light but fairly rigid) and put a 0.75"+ thick layer of polystyrene foam between them (or use bubble wrap if you have no polystyrene handy). Ideally the 3 layers are glued together but you'll get a quick idea without worrying about gluing. It's much quicker and easier than trying to balance floating shelves on semi-inflated bicycle inner tubes.

[jeffreybehr]

Coupling v. decoupling is a controversial subject.  The problem apparently created by your coupling is what Steve Herblein tries to solve by decouping equipment from their supports with energy-absorbing feet, etc.  Says he about his IsoCups--"Pillowy soft, platimum-cured silicone reduces glare, fuzz, sibilance, artificial harshness and other anomalies caused by microphonic vibrations." 
. 
I used them under 2-different pairs of ASL monoamps, where they reduced edginess in the sound slightly.  About the material, he writes--"Herbie's isolation materials are proprietary silicone-based vinyl elastomers with varying compliance and firmness qualities. The materials will absorb vibration with very little pressure applied. As weight load increases, the materials become increasingly resistant to compression. Unlike Sorbothane, Vibrapods, Isonodes, Clouds, and other squishy isolation materials, these compliant, non-vulcanized (sic) compounds are not dependent on a precise weight load to be most effective."

You might try them.  I have this sixpack of them (plus the set of harder balls) surplus now that I use MUCH lighter amps (and 3 of Herbie's Tenderfeet* under each).  Paul, since I know you're a goodguy, I'll loan them to you to try for the price of the postage.

FWIW I agree with George that you should not decouple your speakers.

* I know the plural of foot is feet, but when foot is part of a brandname, does is still change to feet when plural?

[ctviggen]

To me, decoupling (including speakers) makes much more sense than coupling.  Just because it makes sense doesn't mean it's true, however.

[PaulFolbrecht]

George - well, I am not completely sure unspiking the speakers will loosen the bass.  Since they ship with spikes I assume Roy intends them to be used, but maybe not.  I know that at least a few speaker makers do not recommend spiking.

Also, I don't have the necessary plates to *not* have the racks spikes - the spikes are the feet and the only thing that can be done is place them on hard discs instead of spiking to the floorboard.

Jeff - thanks very much for that offer!  But I don't think they'll work - the feet on my amps are only about 1/2" wide at the end and almost an inch tall - obviously, already intended as absorption devices.  Plus I'd need eight total for both amps.

I think I'll mail Tate of Custom Isolation and see what he recommends.

[ctviggen]

Isn't that the argument -- that coupling to the floor will prevent the speaker from moving and therefore won't loosen the bass?  I'm just not sure about this argument. I have a VMPS Larger subwoofer that's placed on an ASC subtrap.  The subtrap has very large rubber bumpers.  The bass definitely does not sound loose to me, but then the subtrap also acts like a trap and further places the subwoofer in a position that minimizes floor-to-ceiling room nodes.  So, I can't honestly say that the sub might not sound better if the bumpers were removed. 

[woodsyi]

Shouldn't the answer be different based on the floor?  Like spike to hard concrete and isolate on wooden floor?  I ended up with same Herbie's "Tenderfoots"  like Jeffrey's for my amps on a rack spiked to the concrete floor.  Speakers are not spiked per Brian Cheney's instruction. 

[DSK]

...I think the solution here, or part of it at least, is to decouple either my speakers or my gear from the floor.  Which one is not yet decided, but I believe probably the speakers' spikes should go.  I know this will result in a decrease in bass extension - it will likely loosen up the bass.

Anyway, I thought this would be a very good topic for discussion in general, concerning spiking, mass-vs-isolation vibration control, etc.  I'm familiar with the various isolation strategies and perhaps another layer under my amps' feet (they have 1/2" rubber feet, on the 2" of acrylic) is a good idea as well....

Paul, your post indicates that you have floorboards rather then concrete floor, but doesn't mention carpet so I'll assume no carpet.

I agree that you want a rigid interface between your speakers and the floor, no rocking that may act against the motion of the speaker drivers. However, this doesn't mandate rigid coupling (spikes) or prohibit isolation. The idea of the plywood/polystyrene sandwich I mentioned earlier is that the polystyrene acts as a lossy layer, a less efficient coupling to the floor. The polystyrene does not have the mass and density to support high amplitude vibrations. As long as the polystyrene/ply base is as large as the speaker base, then it will still offer a firm base for the speaker and not induce rocking like most 'soft feet' will. The speakers should be spiked to the plywood layer (use small metal spike cups if necessary to prevent spikes burrowing into plywood) which itself is lighter and less dense than the speaker, thereby raising the resonance frequency and lowering the resonance amplitude so that it is easier to isolate or damp. The polystyrene is about the closest thing we can get to air while still offering a firm base for the speakers. Yes, I realise that airborne soundwaves/vibration can induce resonance in the objects in the room (including floor), but I'm not sure we can do much about that as playing music in a vacuum sort of defeats the purpose. 

If you have board floors, without carpet, you don't even need the bottom layer of plywood. Just place the polystyrene layer between the floorboards and the upper plywood layer. This doesn't have to be your final solution, but it costs almost nothing and will very quickly demonstrate whether the floor vibrations from the speakers are reduced. You can spend hundreds of dollars on Symposium speaker platforms (that follow similar principles) etc but the difference between these and the ply/polystyrene platform is likely way less than that between the ply/polystyrene platform and your current setup of spikes to floor. Given that such a platform is still very firm, your speakers' bass should not lose extension or become loose. If anything it should become cleaner and tighter. Some listeners may initially hear it as 'lean' but then come to notice increased bass detail and control.

It is often argued that rubber and similar compounds have an elasticity that delays then releases energy rather than damps it. And, anything pliable enough to be termed 'soft feet' is likely to cause speaker movement. Roller balls etc offer a rigid vertical base but will still cause forward/backward motion of the speaker (or sideways for side mounted drivers) as this is how they attempt to dissipate energy. Whether the degree of lateral movement is sufficient to cause audible changes ...

Sorry if you already know much of this, or even disagree with it, but hopefully it offers food for thought for some readers.

[jhm731]

Another source for isolation material:

http://www.kleintechsys.com

[rajacat]

I'm currently building speaker stands for my Omega Hemp Bipoles.  Wood floor with carpet. The stands will be filled with sand and  lead, steel or some combination and built of MDF. Which would be the best option?

1) Spike the stands to the floor, Blue Tac the speakers to the stands.
2) Spike the stands to the floor, spike the speakers to the stands.
3) Spike the stands to the floor and use a composite dampener such as Herbies Tenderfoots under the speakers
4) Spike the stands and use wood, such as ebony between the speakers and the stands.
5) Some other method of isolating or dampening the stand connection to the floor?
6)  ???? open to suggestions
 

Raj

[gooberdude]

Hey Paul,

i think you should look at isolating your rack first, then address the amps, then last the speakers.

Removing spikes might be a bad idea, but getting new spikes that do more than hold the cabinet steady might be worth looking into.

I think you are local to me, i could drop off a pair of Auralex Subdudes for a weekend if you want to fully decouple your speaks and see how that goes...


matt

[PaulFolbrecht]

Tate Blanchard, who made me my killer Custom Isolation rack & amp stands, graciously offered to send me free of charge some matching isolation discs.  I will try these and report back!  I can't imagine why I *wouldn't* want to isolate the gear, with the speakers & subs anchored to the floorboard.  Anchoring the gear racks to same seems near madness now that I've been thinking about it...

[gooberdude]

Removing the spikes in my rack brought about a profound & positive change, but i'm on concrete.   In the same week i had the spikes from my Thiels removed & then from the rack itself...one of the best free tweaks i've come across.