To spike, or not to spike...?

[Daddyjt 9,585]

Just curious what the opinions are on the benefits of spiked feet on speakers.  I am running Klipsch RF7s, and they came with screw-in spikes for the "feet".  Should I install them?  My speakers sit on carpet, which is over a concrete basement floor.

 

Any and all suggestions welcome.

[jazzman53 1,276]

I use spikes on my speakers, which added stability over my thick carpeted floor, but I think the alleged sonic advantages are just snake oil.  

[SteveFord 1,118]

If you have them, give them a shot and see.

You'll probably agree with Jazzman but you never know until you try it.

[PDR 1,194]

My last set of speakers sat on small casters.

I always planed on spiking them but never did.

On my new speakers I was using Ricks risers until

I found where I want to place them, then was going to spike.

But a few days ago I placed them directly on the floor and tilted

them back a bit....as per the design.....using a couple of magazines

as lifters. I think I'm going to try a couple of ball bearing in the front

and see what happens, I'll drill a small impression so they dont float around,

and let the back end sit on the floor.

Spikes have always been a pita to move the speakers around.

But, it doesnt hurt to try them if you have them, I have a bunch here

that I've had for years, and prob one day when I'm bored they'll

have a go. 

[Daddyjt 9,585]

Copy that on the pita to move. Also, trying to convince the wife that there is a reason for 100lb speakers to sit on spikes, AND that said spikes will NOT hurt the carpet...

[Daddyjt 9,585]

I guess I am also curious about the whole "de-coupling" thing as well... They sell special feet, matts, and platforms for amplifiers and other components to sit on... I suppose I can see the benefit for a turntable, but not so sure about anything else. Not trying to be ignorant, just curious.

[mbskeam 1,975]

read on.....

 

http://www.whatsbestforum.com/showthread.php?4253-Understanding-Coupling-Decoupling-with-particular-reference-to-loudspeakers&highlight=spikes

[PDR 1,194]

Interesting article, especially around page 6 or 7 where it was asked if the coupling methods, if they work that well,

could be measured.......then it got all fairy dusted. Funny Amirm didnt chime in with his usual 10 thousand word essay,

being the measurement guru he is. Not in your own back yard I guess...... 

[Daddyjt 9,585]

Thanks for the great link - interesting article! Although now I am really confused....:-)

[Papajoe 221]

I think that the spikes on a rug rely more on penetrating the rug and contacting the floor below it. It may seem silly to place a large, heavy speaker on pointy spikes and expect it to 'couple' with the floor better than just placing the speaker on the floor.

Logically, a big flat speaker bottom sitting on the floor/rug should do a better job of coupling with the floor than pointy feet. But, that is far from the truth. Take for example, a speaker that weighs 100 lbs. If you were to put a scale under each corner, they would read 25 lbs each. But, that is spread over the area of the scale surface area, maybe 1 Sq. foot. So you could say that the speaker weighs 25 lbs/sq.ft . Now, when you put the large end of a spike under the area that the scale was measuring, it is now supporting that 25 lbs. But since the large part of the cone, which is 1 sq inch, is supporting that 25 lbs now, the force on the top of the spike is now 25 lbs per sq in. But, that is not the main fact, since the spike is a cone all the weight at the top is transferred to the point at the bottom, now. Since the point is relatively sharp, say only 1/32" diameter, it is .0002 Sq inches, now that 25 lbs is being applied to the .0002 sq in, which is 125,000 lbs/ square inch, that is the coupling force of the spike.

That also comes into play with a phonograph needle, you may put 2 grams force on the top; but, the force that the tip actually applies to the record is many, many time more than that.

Papajoe

[PDR 1,194]

So how do you guys think this applies to Open baffle speakers like mine, or the Amazings?

I would imagine the same principles apply. But do you think theres a benefit? 

The floor in my room sits directly on concrete with 2x4 on the flat shimmed every 6"

and fastened at each shim point, the void is stuffed with insulation and there is 1 1/4"

of sub flooring glued and screwed on top. There is no give.

I guess the only way to see if theres an improvement is to try them out.

If I have time this weekend I'll give em a go. 

 

[Daddyjt 9,585]

A bunch of incredibly interesting info - thanks! One more question - so for amplifiers and other electronic components (with the exception of possibly turntables), there is no force being generated - so is there any benefit to (de) coupling?

[Schurkey 139]

FIRST, we need to address coupling/decoupling.

 

Both processes have to do with vibrations of the audio device. The difference is whether the vibrations are created by the device, or if they are external to the device.

 

All the source components and preamps/amps are for practical purposes not generators of vibrations. Sure, there is some very minor vibration of components with moving parts like disc players (including turntables) but the point is to keep other vibration OUT of those components. They are DEcoupled from the rest of the room typically with some kind of "cushion" that doesn't transmit external vibration into the component.

 

Speakers, on the other hand, serve no purpose unless they're CREATING vibration. Here's where Newton's laws of motion come in handy: For every action, there is an equal and opposite reaction. Every time the motor structure pushes a driver cone in or out...the whole speaker cabinet is being pushed the opposite direction. Things are worse when the driver is mounted high in the cabinet, so there's a long "lever arm" between the vibrating driver and the base of the cabinet. Only inertia and the mass of the cabinet prevent this cabinet vibration when the speaker is sitting on a big, squishy "cushion" like thick carpet. The result is that the speaker cabinet is providing a low-level, frequency-dependent anti-phase signal to that of the driver (exactly what we DON'T want!)

 

The point of all of this (pun intended) is that if you use spikes to pierce the carpet and pad, so that the speaker is solidly connected to the TRUE floor, the floor absorbs some of the force that would have the speaker cabinet rocking on the carpet. The strength and mass of the floor stabilizes the speaker cabinet--if the speaker is COUPLED to the floor.

 

Since the real problem is the speaker cabinet vibrating with the motion of the driver; the thicker and "plush-er" the carpet, the worse the sonic degradation. A speaker cabinet wouldn't need spikes if the normal plastic feet were in contact with the bare floor. The purpose of spikes is to pierce the squishy floor covering, and in the case of carpet, since it's a woven fiber, the spikes do no more damage than a sewing needle does to the fabric of your clothes.  Hardwood floors probably do NOT need spikes, although the stabilizing effect is probably less than with concrete due to the wood floor's relative lack of strength and mass.  For God's sake, do not fall into the marketing crap whereby first you have to buy spikes to couple the speakers to the wood floor, and then you have to buy protective cups so the spikes don't damage that same floor.  Either spike to the true floor...or just leave the OEM plastic "feet" in place.  Protective cups do the exact opposite of spikes, using them together is a double waste of time, money, effort, and enthusiasm.

 

On typical "box" speakers, I prefer three spikes to four--that way there's no problem similar to having a four-legged restaurant table, with one leg a touch too short.

 

I would put a power drill to my head rather than buy >$30 spike sets. I make them by installing tee- or hurricane-nuts into the speaker base (if a threaded insert isn't there already) and then buying nuts and bolts of the appropriate length and thread pitch at any hardware store. Cut the heads off the bolts, sharpen the bolt shank on a bench grinder, and when final-adjusted for stability, tighten the jam-nuts to lock the studs in place. 1/4-20 nuts and bolts are my first choice, but if there are already threaded inserts in the speaker cabinet base, buy whatever size nuts and bolts fit the existing threads. If the spikes are short enough, they'll be invisible and give the appearance that the speaker cabinets are resting on the carpet--so there's no need to buy "pretty" spikes. Home-made spikes would cost less than $5 for a set of six...plus some labor.

[Daddyjt 9,585]

Thanks for the succinct reply, Schurkey, and welcome to the site. I did install the spikes that came with my RF7s. It was a bit of a PITA, to get them to where they didn't wobble (that whole 4 leg restraunt table thing). I can't honestly say there is an audible difference, but it makes me FEEL better, knowing they are solidly coupled to the concrete under the carpet.

 

Eliminating my toe-in on my mains however, DID create a surprising audible difference. My soundstage opened up considerably:-)