# Spikes vs Foam Floor Isolation



## Megalomaniac (Feb 12, 2007)

Just found this article. It makes sense to me, but I would love it we could bump our heads together and expand more on this. Why? I love to hear others thoughts and learn more. I always thought spikes cause distortion, like a record player the needle transfers sound through bumps and valleys using a tiny needle tip. 

If you want to read full article here:
SD damping feet for loudspeakers

key notes:



> Every loudspeaker rests on a surface that can be compared to a spring, even though the surface may be quite hard. As a result, a resonance appears within or outside the loudspeaker's frequency range. Below this resonance frequency the loudspeaker is coupled to the floor, and above this resonance it will be more or less isolated from the floor.
> 
> The traditional approach has been to try to make the suspension so stiff that the resonance might be placed above the audible range. This is one of the basic ideas behind the use of "spikes". However, this approach does not work. The resonance between the cabinet and the floor will not be any higher than the upper bass range. Not even a concrete floor will do, as anyone who has drilled a hole in a concrete wall will be aware of after having experienced the resonances and sound transmission in this material.
> 
> ...





> The conclusion that the resulting movement is small enough not to cause any trouble is surely correct. One could however get an implied conclusion that spikes could improve things ever so little. This is simply not so. *A high Q resonance will multiply the movements until they become quite noticeable. The free floating approach should be the goal.*











_Sinus signal 125 Hz to the speaker (top),
floor movement below, using soft feet.
Floor signal magnified 2 x. _









_Sinus signal 125 Hz to the speaker (top),
floor movement below, using spikes._




> Spikes can give an open but slightly hard and distorted sound, which some may say is more musical. But resonances and overtones in the floor are equivalent to harmonic distortion in the amplifier.
> 
> A soft overdamped support where the resonance frequency is a little too high seems to make the music sound dull.
> 
> The use of "Blue Tack" or damping feet with extremely high internal damping can be compared to a car with too hard shock absorbers, where much of the vibrations will pass through even if they are not amplified.





> Serious turntables should already have an internal floating chassis with a resonance much lower than the already low resonance frequency of the tonearm/cartridge combination. The introduction of a third series decoupling resonance would fail unless it was lower than 1 or 2 Hz.


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## ccdoggy (Jul 2, 2006)

So they are saying that the speakers I have spiked into the concrete subfloor (below a layer of carpet foam and thick carpet) is causing the concrete to resonate and thus put out distortion. 

I could possibly agree with it if it was on a weak wood floor, but the infintessimal amount of energy transmitted into the concrete and causing it to vibrate I dont think would make a difference on listening and or distortion.

I just dont get how they expect to have a bookshelf speaker to cause enough vibration through the stand then through the spikes to get into the concrete and to actually cause that mass to move very much at all. 

Sure the top graph looks better but thats because the vibrations are not entering the ground due to no strong bonds between them. but if those vibrations are not entering the floor that means they are staying in the speaker/stand and well wouldent that be distortion too?

Isent the whole point of spiking speakers to take the enclosure's vibrations and ground them to something solid so that they are eliminated as fast as possible, thus removing as much 'enclosure distortion' as possible.

SO in that bold part they are trying to say that the stored energy in the form of waves in the speaker/stand will bounce around more if it is spiked and even magnify the waves as they pass though. and that 'free floating' is the best way to get rid of such waves.

*disclaimer* I really dont know a ton about speakers and wave stuff, this is all inference with what i believe to happen in a speaker and what i have experienced.


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## Megalomaniac (Feb 12, 2007)

I think they are talking about high powered subs for the most part...


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## ccdoggy (Jul 2, 2006)

I went to the site and throughout they kept talking about 'loudspeakers' not necessisarily subs, the only sub mentioned is a 8" they did a test with.

Also I am taking what they say with a grain of salt as they are selling a product and its their 'tell you why your setup sounds bad and our product will help' page. Cant really trust them to have honest results when they are trying to sell the product that 'fixes' the problem. Also they are saying to put them under cd player to dampen them...

I have a pretty high powered diy home sub, 12cuft tuned to ~13 hz, 15" driver, 1000 watts. Now i know i dident brace it as much as i could have and i know its causing distortion as the sides are not that secure. The point of Spiking is to make something more solid then it is, give it more strength to resist movement as with internal bracing. prevent erroneous waves from propagating and trying to exit the system and cause distortion. I see the spikes as improving the rigidity of the system and thus reducing unwanted vibrations, and would do so even if i had built the enclosure better.

making sense?


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## bobduch (Jul 22, 2005)

Does your sub fire down or forward?
I have B&W Matrix/3 801s. Years ago I put them on Sound Anchor stands and Goldmund cones which screwed onto the stand (3 cones/speaker).
Difference in bass/midbass was HUGE. There was no A-B test. Didn't need it. I would never had believed the difference if I had not heard it myself. I believe most of that difference was not a reduction in cabinet vibrations, but rather that the driver was held firm in position. When a driver pushes air out it produces Mr. Newton's counterforce, i.e. pushes the cabinet back. The cabinet "gives" thus the driver is moving backwards while pushing air forward. Distortion from the original signal results. Impact is reduced. The heavy stand and cones "anchor" the cabinet to the floor thus when the driver pushes forward the cabinet resists backwards movement, thus lower distortion and in my case much tighter, more accurate bass/midbass. Like I said, the difference was so big I had a hard time believing it. Of course B&W did/does extensive research in cabinet vibration thus those cabinets probably have less resonance than most to start with.
So if your sub fires forward try some screw in cones. If it fires down try putting 300 pounds on top of it.


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## ccdoggy (Jul 2, 2006)

I wish i could test spikes with my sub but sadly where it is located on a old wood floor i wont want to damage it.

I have experienced the difference between spiking some bookshelves in a client's home and the difference was an improvement for sure. and it does make sense as it does cause the enclosure to have more strength to resist the opposing energy caused by the woofer and thus give the driver that little bit extra excursion to dig a little deeper in the freq range.


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## Attack eagle (Nov 18, 2006)

huh? the counter force already exists... it is the other side of the speaker cone.
The motion of the cone is balanced by the force used to move it. 

Any other explanation flies in the face of newton's 3rd law. 

I have always understood spikes (and other heavy stands etc) as an attempt to couple and transmit vibrations from the cabinet TO the floor, not to dampen them. A spike increases the coupling between the floor and the cabinet by reducing the contact patch (more psi). Turns the floor into a passive radiator if it resonates at an audible frequency, or even if it doesn't then you still get infrasonic floor vibrations. Works great on carpet because it reduces the contact patch making it less decoupled.


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## ItalynStylion (May 3, 2008)

bobduch said:


> Does your sub fire down or forward?
> I have B&W Matrix/3 801s. Years ago I put them on Sound Anchor stands and Goldmund cones which screwed onto the stand (3 cones/speaker).
> Difference in bass/midbass was HUGE. There was no A-B test. Didn't need it. I would never had believed the difference if I had not heard it myself. I believe most of that difference was not a reduction in cabinet vibrations, but rather that the driver was held firm in position. When a driver pushes air out it produces Mr. Newton's counterforce, i.e. pushes the cabinet back. The cabinet "gives" thus the driver is moving backwards while pushing air forward. Distortion from the original signal results. Impact is reduced. The heavy stand and cones "anchor" the cabinet to the floor thus when the driver pushes forward the cabinet resists backwards movement, thus lower distortion and in my case much tighter, more accurate bass/midbass. Like I said, the difference was so big I had a hard time believing it. Of course B&W did/does extensive research in cabinet vibration thus those cabinets probably have less resonance than most to start with.
> So if your sub fires forward try some screw in cones. If it fires down try putting 300 pounds on top of it.


^Ying
\/Yang


Attack eagle said:


> huh? the counter force already exists... it is the other side of the speaker cone.
> The motion of the cone is balanced by the force used to move it.
> 
> Any other explanation flies in the face of newton's 3rd law.
> ...


Which one are we going with? Anyone else have a decent explanation?


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## ErinH (Feb 14, 2007)

I like the idea of soft feet/rubber pad over spikes. I would think spikes would just transfer the energy to the floor and you would have tactile energy at your feet or even in your seat if it transponds into the room. 
Soft pad should absorb this.

At least, IMO.


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## ItalynStylion (May 3, 2008)

bikinpunk said:


> I like the idea of soft feet/rubber pad over spikes. I would think spikes would just transfer the energy to the floor and you would have tactile energy at your feet or even in your seat if it transponds into the room.
> Soft pad should absorb this.
> 
> At least, IMO.


I have soft pads on my Peerless Twins. I use those rubber stoppers that you can pick up at Lowes in the hardware isle in the drawers. As for my latest monstrosity, it has no feet of any kind. The base weighs about 50lbs and the pipe/enclosure has to weigh in around 120 with the sub in it.


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## ErinH (Feb 14, 2007)

This would be where I'd look:
McMaster-Carr


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## 2chGUY (Feb 1, 2009)

I would have to side against spikes.

Unless your building your crossover from scratch and have the ability to place the cabinet/finished baffle (with spikes) in your listen area for R&D, promoting resonance into the floor is a bad idea.

I doubt mid/low tier manufacturers take into consideration room construction, and truly high end companies build their cabinets with purpose. So, in the later case, why would you pay $20k+ for speakers and then doubt how they were built...?

lol... I guess what I'm trying to say is: If your building from scratch. Try both and tweak XO construction as necessary. If you're buying prebuilt, do your best to prevent the transmission of resonance....and that means no spikes.


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## chuyler1 (Apr 10, 2006)

Interesting article about spikes...
Speaker Spikes and Cones ? What?s the point? — Reviews and News from Audioholics

What I have found, is that spikes are good for sound systems that do not produce much sound below 50Hz. if you have a dedicated subwoofer as in most HT setups you don't need spikes on your other speakers. If you do not have a dedicated subwoofer, spikes will transfer the low freq energy into the floor and provide a little more low end. They do not isolate, but just the opposite, transfer the energy to something larger which can act as a sound board. The cost and design of the spikes I don't see to be of importance, but rather how they are installed and how well they pierce the carpet and distribute the weight of the speaker to the floor. 

Take for instance one of those aurora bass shakers. What will sound better, provide more output. putting it on your carpeted floor, or bolting it to the wood underneath? 

As for the other side of the spectrum with soft/spongy/rubbery/whatever isolating feet...I only see that possibly benificial with a turntable. i find it hard to believe that silicon chips need isloation beyond perhaps some cheap rubber feet you could pick up at walmart. If they did, then we'd have to make them all wireless so vibrations don't transfer through the cables!


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## hobie1dog (Apr 9, 2008)

This has been argued many times in the home audio sections of other forums....I couldn't tell any difference when I added spikes to my large speakers.....I like the thought of a sponge material that would isolate the speaker totally...like on a gel pad


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