Spikes under speakers is another cure in search of a disease - to borrow a medical metaphor. I am unaware of any speaker that is affected by woofer/driver motion. Another marketing ploy to get the gullible and insecure to spend more money!
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You have a pretty good grasp of the basics of vibration control. At least in terms of- yes the mass of the speaker is so great compared to the moving mass of the cones, etc the cabinet isn’t going to move hardly at all. So holding it fixed isn’t really relevant. But if we were going to try and hold it fixed the last place we would do it is some dinky spikes way at the extreme far end of a lever arm. So you got that part pretty good.
Nevertheless, if you do try different things and compare you will hear there are indeed real differences. Just about any spike or cone will be better than what you are planning on doing. Will tell you why in a minute. For now just accept that whatever you can imagine, I have done it at one time or another over the last 30+ years and not only with speakers, but everything else from the amp to the conditioner to the freaking step down transformer under the floor.
The best solution of all, and for all of these, is springs. Why? Because: ringing.
No matter what we do, no matter how rigid or massive, no matter if it is wood or concrete or carbon fiber, it is gonna vibrate. Look at my system. That rack is solid concrete, 4" thick cast concrete shelves with 1" of sand and 4" solid granite. The legs are cast concrete. People will say you don’t need this or you don’t need that because: concrete floor. Such people are so full of it they don’t even know. Concrete transmits vibrations just fine. I know from experience. https://systems.audiogon.com/systems/8367
Each material has it’s own inherent vibration characteristics, the speed and frequency it vibrates at best or most, and also the ones it vibrates at least or damps. The vast majority of vibration control on the market today (or ever) is nothing more than people played around to find a combination of materials that resulted in a favorable or benign acoustic signature. Hard to explain, maybe even harder to understand. But play around with these things enough you will hear it.
The speaker (or other component, they are all the same) does not need to be held rigid. Quite the opposite. It needs to be free to move, and as independently of the environment as possible.
Why? Because when the component is the only thing vibrating then the vibrations it generates settle down so much faster. Any coupling to the environment, be it a shelf or floor or whatever, and it will set the whole system to vibrating, and those vibrations will take a lot longer to settle down.
This can actually be seen via a seismograph on a speaker. https://youtu.be/BOPXJDdwtk4?t=8
The key element in all of this is that the spatial information that tells us precisely where a sound is coming from is extremely subtle and low level. Ordinarily the ringing created by the speaker/room vibration system smears a tremendous amount of this detail. When something as effective as Townshend Podiums are used they break this ringing feedback cycle resulting in a tremendous improvement in clarity and detail.
I can tell you from actual experience the plan you have will be no better, and maybe even worse, than nothing. Bolting maple to the bottom of the speakers will only add a little mass, but not very well damped mass, so it will mostly add smearing. Putting spikes under it will not help at all. Better in fact to put the spikes on the speaker, and the maple on the floor. You can experiment if you like. Most guys sorry to say come here pretending to ask but really already having their minds made up. Hope that’s not you. I am not kidding. That idea is not good.
Springs are so much better a solution that even dirt cheap Nobsound springs are better than just about anything else you can do. They aren’t perfect. They require a bit of experimentation to determine the correct number of springs to tune the sound to what you want. Then more experimentation and tweaking to get them level. But in terms of price/performance they will beat just about anything.
About the only thing they will not beat, not even close, are Townshend Podiums. These are engineered with just the right amount of damping to tune out the tonal aberrations that would otherwise be a problem with springs.
I tried all this stuff. That was your requirement. I actually did it all. Springs are way better than anything else- except Townshend. Podiums under your speakers will open up the sound stage deep and wide, with so much detail you will wonder if it really is the same speakers. Truth of timbre will be like a whole component upgrade.
Notice the one guy in the video said they had what they thought was a room problem with bass modes. I had the same thing. Was just about convinced I was going to have to break down and try bass traps. Put Podiums under my Moabs, hey where’d that bass resonance go? There is still some room resonance, but it is so much less it is hard to believe. I am now convinced a huge amount of what we consider room acoustic problems are really rooted in the speakers exciting the whole room to vibrate by not being properly isolated on springs.
I am a Electrostatic Speaker user for many years and in the past few years have used occasionally a Three Way Floor Stander.
To get the best from the Floor Standers during earlier occasions of use I have used various Sub Plinths,
that in the end become a Two Tier Sub Plinth,
using a highly compressed Chip Board as the Base Tier, that is Spike Foot coupled through Carpet to a Concrete Screed Floor.
A 40mm Thick Granite Slab is the Top Tier, that is Spike Foot Coupled to the Chipboard.
The Materials chose in the Sub Plinths were selected from a variety of used materials.
The Speakers were seated directly onto the Granite and as an alternative seated with onto the Granite with Spike Coupled Feet.
The Speakers were at their best 'in my view' when the Spikes were used as feet.
When used during this time period, I also had a selection of Dumbbell Weights seated on the top of each Speaker Cabinet.
I recall that by moving the weights off centre into different positions had the effect that I would refer to as a attenuation and could produce a very slight change in how the sound is being perceived.
Very recently I reintroduced the Speakers into the System, they were allowed to see the light of day after a long term storage and used in the New Listening Room Space I have recently created.
I worked my way methodically through their Setting Up and settled for the above set up.
It was for myself, being perceived as being correct in many ways, the result being,
the Speakers were much more impressive in the New Room, when recollections of their previous usage were taken into account.
I am yet to add the Weights to the Top of the Cabinets
I had a opportunity to trial the Speaker Set Up a little further, using a change to a footer, the good impression they were making was a stimulus for the extra investigation.
I had produced similar things for others in their Home Systems and the impression made was enough for those who experienced to create similar Set Up using either Townsend or Gaia Footers
I Seated the Speakers onto Audio Technica AT-616 Pneumatic Feet and was left thoroughly captivated, the effect on the SQ was not expected.
The impact they were having on the SQ was quite noticeable and further enhanced my already good impression.
I have one more trial to undertake, which is to protect the AT 616 Top Surface and Place them under the Speakers Spiked Feet.
I will say the Spiked Footers under the Speakers when used on the Two Tier Sub Plinth Set Up is allowing for a imaging and Soundstage with a defined edge. ( A Electrostatic Mimic )
The AT-616 have blurred the edges ’very slightly’, giving a richness to the presentation with a noticeable weight underpinning the performers.
The Soundstage is now perceived without a Boundary and the experience has that added effect of being more honest / believable. ( This has made such a impression on me, afgter Twenty Plus Years of Electrostatics, they are now in Storage, allowing for myself to get the most from this Set Up )
I fully concur with @millercarbon. An alternative to springs is the Symposium Svelteshelf on rollerballs. Whatever you put under the speakers if they are floorstanders, should be relatively thin, otherwise you need to lift your seating position by a similar amount to get adequate vertical allignment. Also note that bass performance is likely to decrease with increasing distance from the floor.
The problem with springs is if they deflect they must rebound. And they of course have their own resonances when they do. So they must be damped. Try driving a car without dampers. So the damping is very much more critical than the spring in its design. Which is why the dampers on your car cost 100x more than the springs. The problem with dampers is they often have their own resonances. Some springs are damped by having trapped air escaping through a hole. For anything other than the lowest of frequencies this is a disaster because the viscosity of the air is both the reason why any damping at all happens and the reason why you are left with another spring in the form of compressed/decompressed air in the damper. And guess what, that air spring has its own resonance... so most spring/damper combos left this long ago and moved to oil based, because oil doesn’t compress and doesn’t add yet another resonation to the system. But the problem with uncompressible liquids is that they are more viscous than gasses, meaning you need a reservoir, seals, etc and this all eats into your profit margin. The next problem with the spring/damper combo is what is the range of frequencies it can deal with. As an engineer you can probably do the maths. Car spring/dampers can cope with low frequency deflections well, but can not cope with high frequencies at all. This is why your car has pneumatic tyres as well, where the air is another spring and the rubber of the tyre has a damping effect. The different spring rate of air in tyres to the spring/damper on the axle is a problem and why the fussy have lower profile tyres - it minimises the air spring conflict of the tyre. And the smallest of vibrations (road texture) is handled in the rubber touching the road alone.
So the issue for audio is - what are the frequencies that are thought to be a problem? Where are they coming from? Are they in the range a spring can react to? If so, can that spring be damped so as to not make the problem worse? Is that damping adding new resonances and again making things worse?
The products marketed seem to me to have very low frequency spring rebound indeed, and have air damping which at higher frequencies will themselves become springs, not dampers. I can not see how at the high frequencies and low amplitude of audio-caused vibration they can have any effect - I think any effect is due to the mountings and fixings (like the bushes on car suspension, which are vitally importance for isolation because they deal with higher frequencies which no car spring/damper can deal with) and not the springs.
I’d like an engineer - mechanical - to tell us here i) whether there is a spring that is effective in the range of frequency and amplitude deflections thought to be relevant to audio through speakers, ii) how such a spring if it exists should be damped, iii) whether a spike or BluTac has solved the problem already!
It’s about transferring weight to smaller area, achieving greater lbs per sq. inch. Good concept, can make a small speaker heavy.
I’ve done spikes, ... gave them away.
Big or medium speakers (or small speakers on sand filled stands) are heavy enough to put on 3 wheels (more weight per wheel than 4) (3 do not need leveling wherever you move them).
Put rear corner blocks not touching floor, just a bit shorter than the rear wheel height to prevent tip-over when moving. Tilt: corner block touches floor.
Move them here and there, find, then use the perfect location for one person (need marks, I have a grid wood floor luckily).
I listen alone and with 1 or 2 friends, when 2, I want good imaging
You can easily adjust toe-in for a wider center for 2 people, push back into the corners for lower volume listening, i.e. when expanding the dining room table, large crowded parties, ...
Thank you all for the considered and well-crafted replies. All of them. I got something useful out of each one, and greatly enjoyed the morning read. I expected a much lower signal-to-noise ratio than I received from you guys--my mistake.
I am not willing to pay for Townshend Podia at the moment. I am, however, willing to spring for (pun intended) Nobsounds and may piddle with some damping ideas in combination. I still need to build fairly rigid bases for the AV 5140s because their footprint is too small to be sufficiently stable against topling (and this will get worse--to what extent remains to be seen--with the addition of springs). The Linn factory bases went missing long ago, and I don’t think they were "all that" to begin with.
My understanding is that whether you use spikes or isolation pads etc. the aim is to minimise the transfer of energy from the loudspeaker to whatever it is standing on. Spikes aim to closely couple the loudspeaker to the floor by concentrating the mass on the points... I guess if you bolted the speakers directly to the floor that would have a similar effect. The other approach is to isolate the loudspeaker from the floor by placing some kind of compliant material between the speaker and the floor to absorb the energy.
In my case I have floorboards on joists which have their own harmonic resonances so I put my speakers on isolation pads. Another approach that might work for suspended floors is mass-loaded vinyl (as long as the floor can take the weight), I have used that with some effect when recording drums.
The most cost-effective DIY for your situation will be a laminated wood platform a couple inches bigger with springs at the four corners. The first one I built was using springs sourced by searching around eBay. This is a pretty good way to go but it does call for a good deal of searching to find the springs with right dimensions and stiffness.
No matter what springs you use, and whether you use a single spring or multiple like Nobsound, it is critical that they be sized to compress about half way under load. Too stiff, they won't compress enough, they won't provide enough isolation. Too soft, they will compress too much. Read noromance's springs under turntable thread, you will see a whole bunch of us noticing the change in sound and how good it can be when this is fine tuned. Mahgister is the champ, he has used weights to tune his to the ounce.
I still have some plain springs under my subs. Gave up on these larger type springs in favor of Nobsound simply because Nobsound makes it easier to tune by adding or removing springs. Also you can make additional footers for your leftover springs. Simply use a 1/4" drill bit to replicate the Nobsound dimples to stick the springs into and you can have all the footers you want from MDF, wood, acrylic, whatever.
Study the Townshend Podiums to understand how to build your platforms. The key is to have the springs come up through the corners into a tower. This allows you to keep the whole thing very low profile. Did this with mine made of MDF, floor clearance was a fraction of an inch, total height increase less than an inch. Three quarters of that was MDF. Use a much stronger hardwood laminate and you could get by with probably 1/2" but it must be laminated for strength as well as vibration control!
This will be quite good. But I have to tell you, to be honest, nowhere near Podium level. With springs you will hear much more detail, the speakers will disappear, and a layer of grain and etch and grunge you probably never even suspected was there will be gone. With Podiums this gets even better, but the improvement in tone, the ability of each individual instrument to sound so much more like it really does, this has to be heard to be believed.
I have some springs Rick sent me, don't need them now with the Podiums. They are sized for Moabs, will work with anything around 120-170 lbs. If rixthetrick doesn't want em back I could send em on to you, if they will work. Otherwise Nobsound, all the way.
Assuming you bolt your speakers to your new maple bases, you can then have some fun trying several different supporting footers and listening for changes and preferences. Choices could include spikes, and also decoupling products such as one of the Herbie’s products like threaded stud gliders, giant fat dots, puckies, or giant fat grounding bases; or springs as MC suggested. A good source for springs, that has a multi-input search tool is Century Spring.
WOW, this is very interesting. I assume all this is for very expensive systems. I've had many set ups for over 40 years. All in the under $10,000 range. I have just moved and my room is in the basement. Primary gear consists of a Hegel H390, Bryston A2 speakers, moderately priced cables, power conditioner, dedicated power line, and room treatments,.
I'm very happy with my sound. I'm using the Bryston spikes on a concrete floor with a very thick carpet and pad. If I would try to experiment changing the spikes to something else the time it would take would make it hard to notice any difference. It's not like just hitting a switch.
Maybe with what I have would not make much of a difference no matter what I use.
Like alot of people say, if you are happy that's all that matters.
Everything vibrates to some extent. We are talking about energy transfer. Star Sound Technologies website is a good place to learn about energy control devices that truly make a difference in the quality of sound. They mostly use brass and iron in their designs. I hope this maintenance tip will help. The drivers placed onto a speaker cabinet must first have equal pressure on all its fasteners to run true and image well. A car wheel will vibrate if the lug nuts are loose.... performance suffers. I bought the Wheeler Digital Firearms Torque Wrench/Screwdriver and torqued each driver fastener to 10 inch pounds. I was surprised how loose some of my driver fasteners were. All of my driver frames now have equal stable pressure within. My speakers image better and bass is more accurate. Best Wishes to you!
To make sound, a speaker diaphragm must move. It's the movement that pulses the air creating sound. For every movement of the diaphragm in out out, there is a corresponding force that must be dealt with. In the case of low frequency drivers, most of this force is minimized by the flexible surround where the diaphragm is attached to the speaker frame. However, some force still transfers to the speaker cabinet. With high frequency drivers, the majority of the reactionary force transfers to the cabinet. In both cases, vibration (however minute) is transferred to the cabinet. Unless these vibrations are minimized, the result is actual small movements of the cabinet taking the speakers along for the ride. This results in SQ smear and loss of detail.
The purpose of spikes is to couple the mass of the speaker cabinet to a larger mass (the floor) in an attempt to create a monolithic mass that will diminish (not eliminate) the effects of the minuscule cabinet vibrations referred to above. The larger the mass, the less effect the vibrations being transferred to the cabinet will have. BTW, putting discs under the points of the spikes defeats the entire purpose of a spike which is to concentrate a mass.
I am skeptical of springs. By their nature, a spring allows the cabinet to move in response to the forces being applied by the pulsating diaphragms. Any movement of the cabinet would seem to interfere with the stable platform a driver needs to avoid signal smearing.
I have a spring trial in process right now if others are interested. I have Townsend Podiums, and three Platforms ordered. I come from a history of B&W 801 Matrix Anniversary speakers mounted on spiked bases filled with 50 pounds of sand each, speakers on their spikes on that base, and 50 pounds of lead shot in baggies on the top valley of each speaker. Midrange/tweeter module bolted down per design but floated on bags of lead to decouple from the woofer cabinet. Today I have Wilson Sasha 2s on ISO ACOUSITCS GAIAs which I like, but I have allowed these "crazy" spring suspension concepts to get a hold of my thoughts. I only share my history to give evidence that I've been following speaker resonance and vibration for a long time and have tried a few things. I plan on starting with the speakers and moving onto the preamp and streamer/DAC with the three platforms. I will post what I hear, take credit for my brilliance if its good, and blame millercarbon if it sucks. (he's OK with the blame, I checked) All that said, I will share what I hear. Should be a couple of weeks.
Wow, way too much book info on this.
I use spokes on the carpet on my speakers.
Do they add or take away? Dont know. Do my speakers sound great,...? YES!!
Better than just sitting on carpet!
They do work, they sit off the floor a little bit, allowing a good tone, sound. I will continue to use the spikes, as sitting on carpet, is just boring.
Thanks Mr Carbon, I had some spare Nobspring isolators in the drawer, very under utilised! I’ve just put them under the corners of my Shahinian Obelisk2 speakers, which until now have been coupled to the floor via their inbuilt casters. An improvement in tonal ‘rightness’ and soundstage positioning of performers. And that’s with one ear a bit congested right now.
I have never set out on the path of placement of Speaker on Sub Plinths and Footers with a Science for what I am doing in mind.
I started out with Steel Mounts for Two Way Speakers, and then ended up filling the Steel Mounts with Kiln Dried Sand and this evolved over many years into variations of configurations of materials.
Today at hand are a selection of Materials to create different configurations of Mounting for a Speaker, beyond the immediate available Flooring.
A Willingness to periodically trial new discovered Materials as continued Investigation has resulted in increased material options over time.
I know today I am attempting to manage a energy transmission and attempt to use this management of energy transmission to allow for a Speaker Presentation that is most pleasing to my own unique preferences.
I use what is learned from these experiences and take them on board for all of my Devices Mounting requirements.
In many cases there is more of a attenuation created through a materials exchange, it can be perceived as more of a change to a devices flavour other than a improvement.
That is about the extent of the Science used today in my participation.
Morning Miller. Boing boing!
A spring so unstiff that it is compressed to half its free length by the mass of the speaker is certainly going oscillate all day long in response to the cone/membrane movements in the speaker and the air moved by them, as well as air movements in the room.
Happy listening to the distortion created.
A spring is an energy store, a bit like a capacitor, so where does that energy go?.. Either back into the loudspeaker or into the floor. So the problem hasn't really been dealt with by using a spring on it's own, it will need further engineering or tuning to ensure the energy is dissipated benignly. If you end up spending a lot of time or money trying to fix the problems introduced by your 'solution' then there's a good chance you
didn't choose the right one in the first place.
Compliant materials like acoustic foam etc. are more like resistors - they are designed to transfer most of the energy into heat and so don't require any further 'tuning'. They don't always look great and they're difficult for manufacturers to make a big profit on (because everyone knows they're just buying slabs of material), but they do the job just fine. However there may be a problem with stability if your speakers have a high centre of gravity.
Look at Wilson Audio for example look at their substantial spikes heavy duty
and use 3/8th thick threads most spikes are not only thin butthe threads are abut loose ,I always use Teflon tape to absorb as well as remove any play in the spike
Ihave outriggers which is a great solution if you don’t have a substantial foundation. Iso acoustics makes some very nice ones for hardwood floors ,
and adapters for ones with rugs. They truly do solidify the speakersbass,as well as focus . Just thinking your house as being on on pegs .for sure to start buy a roll of Teflon tape at any hardware store and wrap the threads 3-4 wraps going
in the direction you will be threading in , if stand mounts throw a bit of spray foam
In thebottom , then dried play sand ,I also bought50 lbs of graphite coated lead shot ,then after shaken compacted with a small woodblock then sealed with plumbers putty then put the top plate on ,much better focus, sound city sell pretty decent outriggers for under $300 a pair.
@pragmasi - the enclosure deforms with transient energies (ballooning inwardly and outwardly), and then (hopefully) returns to it's natural shape within milliseconds. Play some loud deep bass music and put the back of your hand gently moving it on different panels of the speaker enclosure to feel it for yourself.
Instead of passing that wave of energy onto another component or the substrate, it aught to compress the spring and decompress the spring.
It will probably not do it perfectly, but like a car it aught to smooth out the ride so to speak. Isolation done correctly, simply works.
I could blather on, however, I'm eagerly waiting for wokeuptobose's experiment. Something many of us have done, and so we'll see what he posts. Because so many of us already hear the difference, I don't think he's going to need more than minutes to be impressed.
Millercarbon, if he doesn't want to try the springs, yeah I'll have them back.
By the way nice write up, the concept surely isn't that hard to understand??
Millercarbon, if he doesn't want to try the springs, yeah I'll have them back.
Well I was able to get it (once it was explained by someone not being a total clown about it).
A spring is an energy store, a bit like a capacitor, so where does that energy go?.. Either back into the loudspeaker or into the floor. So the problem hasn't really been dealt with by using a spring on it's own, it will need further engineering or tuning to ensure the energy is dissipated benignly.
That is the beauty of Townshend, Max uses an ingenious air valve that provides just the right damping factor. Clearly explained in my Townshend Podium review.
Ordinary springs by the way do work a whole lot better with a whole lot less problems than you seem to think. Essentially what happens is the springs by isolating the speaker allow the whole speaker and the whole speaker alone to dissipate the energy. All other methods such as cones, spikes, mass loading, etc inevitably wind up exciting the floor, etc, all of which ultimately comes right back into the speaker creating a situation where the whole speaker/room is ringing.
In other words, the situation is we can either have the speaker alone vibrating and ringing, or we can have the whole room and everything in it vibrating and ringing. The second is much worse. Springs are the least bad answer. Townshend springs with optimal damping are even less bad than that.
Before you go the very elaborate routes that you have planned and other suggested here (all of them very valid and with varying degree of expense and difficulty to achieve the end goal) may I suggest you try the appropriate size "PRIMACOUSTIC" Recoil Stabilizers under your speakers. These are very inexpensive to experiment with and in my opinion one the best additions I made to my system. Read the scientific data sheets and check out the list of professional engineers and artists that use them. one of the things about professionals is that (a) they know and trust their ears and only use products that actually work and (b) they don't want the spend a huge amount of money to achieve these improvements.
In other words, the situation is we can either have the speaker alone vibrating and ringing, or we can have the whole room and everything in it vibrating and ringing. The second is much worse.I respectfully have to disagree
The perfect production of a sound wave requires that everything (driver frame, cabinet, etc.) be totally rigid so that only the speaker cone moves. Any movement (vibration) of the speaker frame or cabinet will add or detract from the pure signal that is being produced resulting in SQ smear for lack of a better term. Coupling through spikes attempts to turn the speaker cabinet into a monolithic mass with the floor and surrounding structures. In doing so, the vibrations that are transferred (not eliminated) become so small relative to the large mass that they little to no effect on the production of the sound wave. Speaker manufactures go through great pains to make their cabinets as rigid as possible and provide spikes to couple the mass to the floor. I am not aware of any manufacturer that provides springs in place of spikes.
I've always been of the mind for the past 30 years or so that the best way to bet better sound out of any loudspeaker was to spike them to the floor. Standmount - spike the stands. Floorstanders - spike the speakers.
I've so been under this belief that I even spiked the 200 lb Dunlavy SC-IVs when I had them. I've also gone as far as nailing my speaker stands into the floor at one point.
Then a few months ago, I called a manufacturer of a particular speaker manufactuer (a small, single 3" driver speaker) to ask them about their discontinued model which I was interested in.
In speaking with him, he told me that the speakers were intended to be decupled from the floor and that the outriggers made for their speaker line had flat, $.25 coin sized plates rather than spikes. I thought this odd since I could't figure out why a small speaker manufacturer wouldn't want to get 'more" bass out of a small 3" driver.
I then started researching this subject of couple vs decouple and, to be quite honest, it became somewhat confusing. I've read that spikes "couple" the speaker to the floor and have also read that spikes "decouple" since it reduces the surface of the speaker that makes contact with the floor.
I've seen Paul McGowen in one of his "Ask Paul" segments say that he feels that speakers need to be isolated from the floor by use of things like Iso-Pucks.
Now, my current speakers sit on Iso-Pucks, which sits on sand-filled, spiked Osiris stands. I've got both bases covered.
BTW, millercarbon. My name is David Webe. I like audio. Hence Audio D (for David) and webe (for, well, my last name Webe).
Just kidding. David Webe isn't my name. But how cool would that be, huh?
clearthinker279 posts03-28-2021 2:05am"...A spring so unstiff that it is compressed to half its free length by the mass of the speaker is certainly going oscillate all day long in response to the cone/membrane movements in the speaker and the air moved by them..."
Newton's Third Law of Motion is not to be denied.
Being so new to this hobby, and seeing how reaction to opinions sometime results in soul crushing blowback, I fear what may come from what I am about to say. I do have insight on this topic that comes from a background of constructing hospitals, research labs and computational spaces and I too am very interested in making the music sound as pleasing as possible. And that is why I started reading this forum. To seek the knowledge of those that have come before.
I am not an academic but have long worked with engineers, architects, and acousticians. Vibration and sound control is a huge battle for these professionals as they care for environmental control that effect patient well being in hospitals and sensitive equipment in lab spaces.
Around 45% of a construction budget is for the infrastructure that is above ceilings, behind walls, and in mechanical spaces that are seldom seen. The equipment used generates vast amounts of noise and vibration that are not constant. Motors, fans, pumps, electrical gear, etc. cycling on and off as demand shifts throughout the day. Spaces within buildings meant to be quiet are sometimes adjacent and present acoustical challenges that must be dealt with. Where to start?
For large pieces of equipment with motors mechanical engineers turn to base isolation. The equipment is bolted to a frame built from suitable material and springs that dampen torque during start up and control vibration during operation. Typically there is a concrete pad under the isolater that is sitting above the floor slab. This approach takes care of most issues however if the need is greater control of the resonating acoustics from vibration enter our best friend, mass. Thicken the concrete pad, further spreading the load, and increase the ability of the supporting framing members and sound transmission diminishes, but is never eliminated.
That takes care of the big stuff, almost. The adjacent spaces may feel less vibration but standard partitions are transferring far too much noise. More mass please! Adding layers of drywall on both sides of the wall stud, adding a wall in front of a wall, insulation inside the walls all are used in combination as needed. Similar acoustical treatment of walls is often necessary for an office space when quiet is needed for long periods of concentration. In larger conference rooms surface mounted wall treatments are often an additional part of the solution.
This is beginning to get deep in the weeds but I am coming to a point.
The bench microscope doesn't hear anything but if vibrations are all around it is rendered useless. Add mass. A heavy countertop will do a better job than lighter materials. However the counter is fixed to a base cabinet and the cabinet is anchored to the floor and the building still has vibration. There is a final decoupling that must happen if we are after optimal results.
Going back to equipment for a final look. Base isolation works well, we know that, but if something weighs say 100-200 pounds it is cost prohibitive to purchase and install those. There is a very effective solution that is used in those applications when the equipment is either sensitive to or produces mild vibration Our speakers are similar to the latter.
My speakers came with a platform and large spikes with sturdy bolts. Very solid point loaded foundation. After accidentally bumping the platform I was left with a deep gouge in the 100 year old inlayed hardwood floor. I spoke expletives and nearly teared. I inverted the spikes so that would never happen again but this forum left me asking did I compromise anything doing so. Here I learned springs were the common go to so I ordered some and patiently await their arrival.
While waiting, thinking has gotten in the way and I started reflecting back on what I have learned over the years about this topic. Some of which is summarized above haha.
We need mass number one. The more the better. But our houses are not built from inferior materials for the levels of vibration we are dealing with. A slab foundation IS mass and quite capable of reducing most of the resonance generated from speakers (I am also suggesting we need as much mass as possible for our components to rest on). Wood frame houses are not as good at this but do have mass enough to work with.
In what seems like a lifetime ago, my youth, so really it was, we used to pile magazines or large books under our speakers to decouple them. Originally I was just trying to get above the shag carpet and didn't realize there would be a SQ improvement. Worked well enough for the money I had in those days.
So finally the end. If I want more mass for my speakers to rest on, fine, but not really as important. I want to spread the load not point it. I nearly purchased industrial granite slabs to sit on my wood floors to solve both points above but didn't want to deal with the 200 lbs. of weight for each piece. Spreading the load means removing the spikes and using the platform only with a decoupler. In the end I went with the same material used for lighter equipment and microscopes to decouple from always present vibrations. Commercial grade neoprene. The results were very surprising.
Once the spring style approach arrives I'll have a small A/B party.
@mgolpoor - the PRIMACOUSTIC product sounds similar to the A/V Roomservice EVPs that have won a bunch of Absolute Sound awards. The AVPs could probably be closely imitated through DIY using Owens Corning 705 fiberglass board sandwiched between sheet aluminum or your choice of hard material. At the end of the day, all of these decoupling products are some form of damped spring.
Pasted from wikipedia:
>>>A 12-inch-diameter (300 mm) paper woofer with a peak-to-peak excursion of 0.5 inches at 60 Hz undergoes a maximum acceleration of 92 "g"s.<<<
This is an enormous acceleration, and a membrane with a mass of 8 ounces, accelerated at 92g, can definitely produce enough impact to move even a heavy speaker back and forth.
I agree with the general recommendation to use springs for vibration control, but the issue of vibration control is obviously frequency and component dependent, and there is not one solution for every issue.
Specifically, I measured a 12" Rhythmik sub, front firing, at minus 3 - 4 dB, when sitting on Nobsound springs (compared to standard hard rubber footers), which obviously allow for horizontal movement.
The loss in bass energy was quite audible.
The measurement was corrected for room modes, so I am pretty sure what was measured and heard was the isolated effect of the Nobsound springs.
In contrast, when using the springs with a down firing Martin Logan sub, no loss in sound pressure is observed. Obviously the force required to "lift" the entire sub by far outweighs the force required to move a sub horizontally, when it is resting on springs with little horizontal stability.
Hudson silicone half spheres are great for subs.
From what I have been told is IsoAcoustics Gaia footers not only prevents unwanted vibration to the room that can effect other cables and electronics of course but also more importantly back to the speakers. Eventually that vibration can travel back like a wave back to the speaker. But we mostly listen in stereo. So we definitely do not want the vibration from the opposite speaker. This can produce unwanted noise or negate the sounds that are intended to be there in the first place. I use spikes that sit on metal discs that sit on the carpet. I can hear the difference between each addition. I am going to try the Gaia footers to see if I get an improvement. I asked my local Hifi store to start carrying them. We will see what happens. Maybe if other people who shop at https://holmaudio.com/
in the Chicagoland area ask for them they will stock them.
hshifi, We had someone recently upgrade from Gaia to Townshend Podiums, they are quite a bit better. Do a search you will probably find others. If you want to save money the Nobsound springs are quite a bit cheaper than Gaia (only $30 per set of 4) and probably at least as good, not Podium level but certainly better than anything else for the money.
@linnvolk, I think you have asked some very good questions and proposed some workable approaches. I have used "spikes" under my floor-standing speakers. In my opinion, the sound was better after the spikes were used than before, particularly in the bass region. I think it cleared up the rest of the audio band too, but can't be sure, without further study. Because the spike may not have been as good a coupler as I assumed, or the isolation is not a full isolation as I assumed, is why I can't be sure, without further work.
I'd suggest that we step through the vibrational chain, every step from speaker motor to the entire cabinet, and to the floor. Let's assume a conical dynamic speaker, mounted inside a cabinet that is sitting on the floor, for the purposes of discussion. The cone can be assumed to move fore and aft, as well as up and down, to cover at least the two most common arrangements - front firing, and bottom firing speakers..
The speaker motor (voice coil) moves the diaphragm.
1. What motions get transmitted to the basket?
2. Then, what motions get transmitted by the basket to the cabinet, when attached?
3. What motions are excited by the air volume inside the cabinet?
4.Then, what motions get transmitted to the speaker base (carpet, no-carpet, spikes,...)?
I've heard that some propose that the driver should be isolated from the cabinet.
I've also heard that the cabinet should be as massive and rigid as possible.
I've heard that coupling the speaker to the floor is an improvement, and also the opposite suggestion of isolating the speaker from the floor.
If we can get answers to 1 through 4, I think we will have a better idea of where the biggest problem lies. Sounds like several of the posters have tried many things already. One of these days, I may get around to really think through this problem.
I do not think this is physically possible. Estimating the speaker weighs 50lbs and the cone and voice coil 8 ounces, the speaker cabinet would move 1/100th as far as the cone, for an equal and opposite reaction, assuming 100% of the energy moves the speaker. The cabinet is larger in surface area, but 3db is a 50% loss in acoustic power. This is not possible.
linnvolk, That is correct. Spikes lock the speaker to the floor. It is the speaker resonating that you are worried about. Play something with a loud bass line and put your hand on the speaker. That vibration you feel is the speaker resonating. Locking the speaker to a solid floor minimizes some of this but not all. Any vibration you feel is distortion. It is usually low down so it is the woofers causing the problem. Because the forces on the speaker are rarely symmetrical the speaker can slowly walk across the floor. I have seen this happen on both wood and carpeted floors. Spikes prevent this.
Some people think that isolating the speaker on springs helps to keep the floor from resonating. This is another example of lay intuition run amuck.
The speaker just resonates worse and the floor keeps resonating just the same. If you want to keep the floor from resonating put the speaker outside. Heavy carpet will dampen it to a degree.
@mijostyn, I wonder if what you are feeling with hand on speaker is primarily flexible modes being excited, which locking the speaker to the floor will not really attenuate.
Spiking the speaker to the floor (if it actually works as intended) would restrict the translational fore-aft rigid body mode, but it would do little about the fore-aft rocking mode. I suspect both of these modes for most speakers are in the sub-1-Hz range. I am skeptical that any true acoustic benefit of spikes derives from them actually anchoring the speaker to the floor, though their ability to keep the speakers from walking might be valuable.
Have you done the "hand on speaker" test both with and without spikes (same music, same electronics, same everything, except with/without spikes)? I have not, but my intuition tells me that you may feel no difference(?) I would put the same question to the "spring and damper" crowd.
Based on anecdotal evidence from others and the differences in opinion regarding the physics involved from experts (Richard Vandersteen and others), I suspect that:
Thanks again for all the input.
For tower speakers on thick carpet, spiking through the carpet it to whatever floor is underneath may be a good idea for stability against toppling.
Spiking the speaker to the floor (if it actually works as intended) would restrict the translational fore-aft rigid body mode, but it would do little about the fore-aft rocking mode.
These statements appear to be at odds with each other.
An accelerometer would quickly put most of these questions to rest concerning cabinet movement at the stimulus frequency. Using multiple placements would allow removing cabinet flex from results. Edges and corners should have least flex.
You caught me in some less-than-clear writing.
The second quote is based on a tacit assumption that we are talking about hard floors. This is what I have, and I tend to default to it without necessarily giving the reader the appropriate cues. My bad. The point here is that putting spikes on a speaker that would otherwise be sitting directly on a hard floor does nothing to help the stabilize the speaker against the rocking mode. They actually will destabilize this mode, because the spikes have to be inboard of the periphery of the speaker base in order to have something to screw into. This reduces the footprint and thus the resistance to rocking.
The first quote addresses, as stated, the case of tower speakers on thick carpet. It is equally or even more applicable to bookshelf speakers on stands (which are likely a more top-heavy arrangement). In this case, the speaker will want to rock back and forth on the springy carpet, pivoting about its base, due to the carpet's compressibility. Here, using spikes lets you bridge across the mushy carpet and get "seated" on hard floor.
I agree with your accelerometer statement. My life is not long enough nor my pockets deep enough to head down that road. Though not part of my practice area, my company could actually do this for several thousand dollars.
I think the "hand on speaker test" with some thumping bass would provide a substantial clue regarding whether spikes or springs are either one changing the game as far as speaker vibration is concerned. I suspect that neither will show any difference in that test, though here, as in listening, perception bias will play a part unless you enlist at least one other person in a blind test so that you do not yourself know which is which. Even there, the speaker on springs will have some perceptible wobble in response to just your touch which you won't be able to ignore/forget.
@aschuh, that would be quite true if the force were static. In your example, that force is reversing direction 60 times per second. No problem for an 8-oz woofer cone. The displacement (vibration) response of the 100-lb sub in rigid-body mode at that frequency will be of very small magnitude as it is nowhere near the natural frequency for that mode. Whether there is enough magnitude to matter and whether the magnitude is attenuated by the use of spikes or springs (and whether that attenuation is good, bad, or indifferent) IMHO would best be addressed by running the test and using your hands/ears...or accelerometers. For the accelerometer testing, please hire my company, have them spend several days on testing (I will write the test report), and send @ausaudio the bill.