DIY speaker isolation base for a wood floor

Anyone looking for rubbery damping materials has a couple more to choose from: EAR Isodamp (used in industry) and Navcom (used in the gun business). One form of Isodamp is made expressly for constrained-layer damping, another for damping of metal parts such as electronic enclosures. Michael Percy Audio sells both. 

I mean no disrespect but I put that horrid blue EAR stuff almost as low on the totem pole as Sorbothane. EAR rubber grommets, sheets and feet look so darn cool, too. Oh,well, onwards and upwards, guys. Anybody actually listen to this stuff or is the March of the Lemmings to the sea? Marigo VTS Dots constrained layer dampers are a no brained. Marigo has various sizes for a multitude of applications, including but not limited to, bottom of glass of vacuum tubes, speaker diaphragm cage, tonearm base, turntable platter, speaker drivers themselves, power plugs, glass windows and sliding doors, walls, printed circuit boards, speaker cabinets.

blueranger,

I am assuming each granite slab is about 25lbs, and the sorbathane is between them, so assume a 100lb total load.

georgehifi posted a link above to an Ebay seller. They sell 2.5" diameter disks of 70, 50 and 30 hardness. My rough calcs say that if you cut those in half (so half circle), and use 4 of them, they should depress about 25%.  That is not going to isolate the lowest bass frequencies, but will be a good improvement over what you have now. One area I agree with geoffkait on is that springs are best for low low frequency isolation.

I expect you have lots of cork around, so you can start experimenting. As opposed to single large sheets of cork, cut them into say 2" squares and stack them say 1/2" high, and use 4 stacks for stability. You want the cork supports small enough (and not too small) that the cork is compressing say 10-20%.

Hey bdp24,

Do you have experience with ISODAMP. We used some for a project a while back, but my colleague was working on that and I did not have enough time for "info-osmosis". I think the foams are quite interesting, and the availability is good. Thanks for the reminder. I will probably get some in the next week or two to try out. I have more experience with Sorbothane so it becomes a go to.

I like this video:   https://www.youtube.com/watch?v=3HRbjfZUbe8

After the first simultaneous ball drop, listen to how loud the next bounces are from the regular rubber material. The foam absorbs the energy and releases as heat, not sound.

Thanks for everyone's help!! I ordered the 8 springs today. They should be here Monday. Ih what fun. Let me put the ideas I have in my head.
1. Use the 4 springs on the floor directly coupled to two 16x16 granite slabs with nothing in between.
2. Same as above but with aluminum cones between the slabs.
3. Same as #2 except the cones on the floor and the springs between the slabs. 
4. Springs on the floor and sorbethane between the two slabs.
5. The springs on the floor with a cork and neoprene sandwich between the slabs.
Ok now which one should work best????? Where's a testing lab when you need one! I'm excited about trying these options. I'm off next week so I should be able to experiment. Again thanks for your input.

6) The one where you get creative and figure out a way to have the springs and sorbothane between the two slabs at the same time ... or maybe the springs and a stack of lightly compressed cork. That way you get isolation and dampening.


Which springs are you getting? If you have them at the bottom, you need the right springs for 125lbs (spring and two slabs). The resonant frequency of the spring is a factor of spring constant and loading.

Oops I don't know. I went by today and they had 6 so I had them order 2 more. I should have taken them home with me. I can call Friday and find out though. This is fine line technical. Thanks.

Should I get conical springs?

If you have large diameter springs and do not overly compress them, you don't need conical spings. Conical springs have better stability the you can make one layer sit within another, but you shouldn't be compressing them that much. It is a bit harder to calculate the operating point for a conical spring.

My original Nimbus Sub Hertz Platform used a SINGLE geometrically correct airspring. It was a convoluted Goodyear rubber airspring that expanded to a height of about six inches with 35 LB of pressure. It was three inches in diameter. The advantage of a single airspring is that you get much lower resonant frequency for the system. That’s how I got below 1.0 Hertz in some directions. The Nimbus was also designed to achieve isolation in six directions.

The problem for a single single in case it’s not obvious is that it is very unstable for any load above about five LB. So I used a clever system of horizontal springs located at the bottom of the airspring to provide the necessary lateral support so that components up to 40 pounds could be isolated with stability. Otherwise the airspring would just flop over. I also incorporated a large auxiliary air canister that was connected to the airspring with a brass air fitting. The top plate of the Nimbus was connected via four 3’ long steel rods to a sub-plate located below the aux air canister. 60 LB of dead weigh were placed on the sub plate to lower the center of gravity, required along with the lateral spring system to achieve stability under load.

The Nimbus was also tricked out so that the top bolt holding the airspring to the top plate was adjustable so that the top plate could be made perfectly level after setup. The “perfect geometry” of the airspring is defined as very small surface area on top and very large internal volume. Hence the large air canister. Voila! 🤗

Well the springs were wobbly. I didn't like it. Geoff does your springs wobble with 130lbs?

Springs are supposed to be “wobbly.” Springs need only be stiff enough for stability. The best isolation is achieved when the component can move most freely in the directions of isolation. The spring rate (springiness) of the springs should ideally be matched to the load to obtain the lowest resonant frequency of the system.

Thanks Geoff! I had a video of me pushing on it but couldn't download it here.  What are the dimensions and wire diameter that You sell? You are a great resource

So Geoff, do you recommend me doing away with my neoprene/cork sandwich and use my two 16x16 granite slabs?

Pushing up and down on the springs when they’re set up is a good way to measure the resonant frequency Fr of the system. With a stop watch count the number of complete up and down cycles and divide the total by 10. If properly set up you should be able to get down to 2-3 Hz (cycles per second).

I like granite slabs a lot because they are very stiff against bending forces. But I eschew rubbery things in the context of isolation. I suggest very hard cones for mounting and stay away from Sorbothane, cork, rubber, etc. as soft Springy materials store or block energy and interfere with the actual springiness of the springs. Energy should be allowed to exit the system as rapidly as possible. 

audiozenology "Wood floor. Assume somewhat springy? ... then usually better to isolate"

Before isolation I would try to load with mass first it is much more likely to work in that type of situation when using a Music Reproduction System speaker.

Blueranger,


Just using springs will be wobbly. If you are targeting 2-3hz resonant on the springs, then most higher frequencies will not be transmitted .. it flops.  If you add dampening in parallel with the spring (ie sorbothane), then you can keep a low resonant frequency, but damp oscillation. Some higher frequencies will now pass (still highly attenuated), but the system will not feel nearly as "floppy" as the resonances are damped.


Wrt Clearthink's post on just adding mass, all that does is change the resonant frequency of the speaker/mass and spring (i.e. your floor). The spring constant, i.e. your floor does not change. As I mentioned above, a wider stiff base (ie your granite bases) does change your floor interface which may transfer weight closer to the joists which will change your spring constant (floor).


Where Geoff and I agree is on a spring loaded floor isolation is better. I prefer damped as that damps out cabinet vibration and isolates from the floor.

Trying to damp spring oscillation is a fool’s errand. For one thing they’re not really oscillating. Where did you get that cockamamie idea? The springs only move when you push down on them. Hel-loo! My springs and probably all springs sound best with no damping. This is not rocket science, folks. You’re making a mountain out of a molehill. Give the the right spring and I’ll isolate the world. audiozenology is trying to make this into some sort of debate. There is no debate here. This is an obvious case of too many cooks spoiling the broth. And don’t flatter yourself. We don’t agree on anything.

If you push down on a mass that’s on a spring and then let go it will oscillate. it’s not a sustained oscillation but it most definitely oscillates. many of us have done this experiment on our car when the shock absorbers were at the end of their life.


I am not trying to turn this into a debate because there is no debate. When you push a mass on a spring it will oscillate at a defined frequency. It won’t sustain those oscillations but it will oscillate. There is no debate it does that. That is literally high School physics. The op doesn’t like his speaker is being floppy. the way to eliminate that floppiness while still having a high level of isolation is to a dampening. A game this is not a debate that is simple fact. There are trade-offs with adding that dampening as I pointed out. That is not a debatable item that is simply fact.

There is a video posted above by select of the Townsend isolation system 4 speakers. That is a good example David damped spring system.  Well I find the video of it cheesy you can see that that system not only isolates the speaker from the floor but also helps to dampen cabinet vibrations.

Wow there us some good points brought up here with passion behind them. Look I do appreciate the gusto behind your arguments and lets keep it respectful. There has to be someone who has access to the right measuring devices. Where is a college physics major who is writing his thesis when you need them? This would be great for a class debate with the tools needed in the same building. 

audiozenology"Wrt Clearthink’s post on just adding mass"

That is not even remotely what I said so I do not know why you would claim, argue, or assert that I had you maybe should consider actually quoting those with whom towards you seek to engage in argument here is exactly what I wrote:

"𝐁𝐞𝐟𝐨𝐫𝐞 𝐢𝐬𝐨𝐥𝐚𝐭𝐢𝐨𝐧 𝐈 𝐰𝐨𝐮𝐥𝐝 𝐭𝐫𝐲 𝐭𝐨 𝐥𝐨𝐚𝐝 𝐰𝐢𝐭𝐡 𝐦𝐚𝐬𝐬 𝐟𝐢𝐫𝐬𝐭"

Using mass "first" does not mean using mass "only" but I suspect you already understand that.

Someone is being argumentative again. The springs don’t oscillate while music is playing. Don’t push down on the springs when the music is playing. That is the same silly argument people use for granite, that is rings when you strike it will a metal object. Well, don’t strike it with a metal object while the music is playing. Duh!

I never said the spring would oscillate with music though with some of the platforms with their rubber springs they actually would. With a well chosen basic steel spring it will not. However as the op stated he found it wobbly and does not like it. Most don't find damped systems wobbly, to that end damping his spread would give most of the benefit of isolation you promote with a system they can live with. 


Granite would be excited by vibrations at higher frequency, but given the mass and relatively low energy at those frequencies it's not going to create audible issues.


The spring only system will not help to damp cabinet vibrations. Damped system will.


Blueranger, you may have a half decent measuring device in your hand right now. Your phone has a multi-axis accelerometer. There are programs for logging / testing. Bandwidth is limited but frequencies are usable.  I have a range of accelerometers in the lab, we can also do non contact, but for a speaker cabinet that is not really needed.

Twoleftears,


Note what I posted earlier in the thread. The primary coupling is acoustic. 

Got a good laugh out of claiming the cabinet does not move in one sentence to claiming large floor coupling the next. Which is it?   Could acoustic coupling be a primary mode of coupling to the floor ... after all, where is the energy coupled, to the cabinet or to the air?

Ethan Winer. Lots of laughs! 😃

Eureka!!!!! I have the answer!!! Suspend the speaker from the ceiling!!!! Case closed! Well NOT. Oh thanks foe the link. I have rad about half. Going back now

@audiozenology, are you hot dogging me? You probably should read what blue ranger wrote one more time. Spring systems are not wobbly unless you push down on them. Duh! You are nothing if not argumentative. Why It’s almost like you don’t know anything about it. 

Interesting article from a snake oil sleuth. I have wondered too if the change was somewhat due to speaker height. I swear my DIY speaker isolation base made a worthwhile difference when I played Madonna's "Erotoica" and Al Stewart's "On the Border" The bass seemed better controlled and deeper. I dont want to think that the expense of time and 💰 money was wasted. That earlier video of the RMAF show was impressive. So according to the article he didn't test that guys product did he? So I'm thinking maybe my DIY speaker isolation platform is making a small but positve step closer to audio nirvana.

geoffkait"Spring systems are not wobbly unless you push down on them."

Of course that is true this is like the old joke.

Patient: It hurts when I do this.
Doctor: Then don't do that.

Oh I did see that Iso Acoustics was tested. So maybe the speakers distance apart had the biggest impact. Ah I like the looks of my bases. If I say this beach is secure. This beach is secure!!!!

Just in case no one noticed this in the Max Townshend video of speaker isolation using springs under speakers works two ways - (1) it prevents mechanical feedback to the front end electronics via the floor and (2) it reduces the vibration of the speaker cabinets themselves. There is a third way, too, preventing seismic vibration from being transmitted from the floor to the speakers, but that seems trivial to me. Yes, I know what some of you are thinking, “Gosh, aren’t speakers like musical instruments 🎻 and supposed to vibrate?” 😳

Geez, I don’t get what all this is all about.....all you need is a critically damped buckling isolator tuned to an appropriate frequency for isolation....and a mechanical diode to take care of all the speaker vibrations, and without the phase issues damping brings to the table.

Easy peazy.

And then everything will be quiet on the Eastern Front.

Speaking of hanging speakers from the ceiling that’s not a terrible idea. I suspended LS3/5a speakers from eye hooks in the ceiling using bungee cords of just the right springiness. That was forty years ago.

You will find that Ethan gets 0 respect here from certain people. I am not one of those people. I don’t agree with him on everything he says, but more often than not he is right. Is he completely right here? While I think he did his best to measure, I am not sure metrology is his strong point, and as he admits, it is a difficult measurement due to consistent positioning. A THD or IM measurement would be less sensitive to position and yield more repeatable results. He was only measuring how the speaker behaved, not if floor coupling was at all a factor. For the frequency response, it is just not an accurate enough measurement in his environment. If you look closely at the impulse responses, for which the resolution is very poor in both the temporal domain and the SPL domain, there does still appear to be noticeable differences. Is height a factor? Maybe. I would have like to seen a measurement farther as well to take into account potential floor interaction (or lack thereof).


One serious issue in the Townsend video is they only take into account the motion of the very light speaker cone w.r.t. how the cabinet would move. This is an incorrect model as it only takes into account reactionary mass (sort of like a rocket where you are "throwing" mass so to speak). In a speaker, the air is a mechanical loading. You are not just moving the cone, but moving the air, and in front of the cone, pressurizing it, so the mechanical force is more than just the mass of the air as well. Put your hands on a wall when loud bass is playing. You can feel it. That is the energy that cone is transferring.

blueranger OP636 posts01-04-2020 3:11pmInteresting article from a snake oil sleuth. I have wondered too if the change was somewhat due to speaker height. I swear my DIY speaker isolation base made a worthwhile difference when I played Madonna’s "Erotoica" and Al Stewart’s "On the Border" The bass seemed better controlled and deeper. I dont want to think that the expense of time and 💰 money was wasted. That earlier video of the RMAF show was impressive. So according to the article he didn’t test that guys product did he? So I’m thinking maybe my DIY speaker isolation platform is making a small but positve step closer to audio nirvana.

Can you explain how you have a damped buckling isolator ... and none of the issues damping brings to the table?  I understand what a mechanical diode is.

all you need is a critically DAMPED buckling isolator tuned to an appropriate frequency for isolation
....and a mechanical diode to take care of all the speaker vibrations, and without the phase issues DAMPING brings to the table.

Utterly predictable responses from gk.

Moving on. The RMAF 2018 Isoacoustics demo is very impressive, and the difference is clearly audible even with youtube "fidelity" and computer speakers. Still, I am just a tiny bit suspicious. The nature of the "improvement" that I hear could also be achieved by nudging up the volume control a tad.

@blueranger   No, you got it wrong.  It's the speaker cables that you're supposed to suspend from the ceiling with monofilament.

Isolation doesn’t sound anything like nudging up the volume a bit. So you think It’s a giant conspiracy designed to suck the money out of naive and gullible audiophiles? You and Ethan Winer. I bet you didn’t predict I would say that.

1. Do Isoacoustics Gaias + cups isolate?

2. I didn't say that.  I said that via youtube and computer speakers that that was what the difference sounded like to me.  I wasn't in the room, nor, I suppose, were you.

It’s perhaps no obvious but the primary issue with isolating speakers is the center of gravity makes it very difficult or impossible to isolate big speakers with high center of gravity without resorting to making the arrangement of springs very wide, much wider than the footprint of the speaker cabinet. That’s why the Townshend speaker pods are integrated into an adjustable frame. Thus the springs can be located to the front and back of the speaker, increasing lateral stability so that the speakers won’t be so wobbly. For subwoofers or heavy components with relatively low centers of gravity springs can be placed directly under them without all the hoopla.

Was just dreaming up an ideal solution....and having a bit of fun. Dreaming aside this is some tough sledding and will always fall on the side of best efforts and never hit an ideal solution. Like isn't a mechanical diode kinda like a holy grail thing, often searched for, but never found ?

Sorry for the fun-ing.

I have had great results with Granite as a singular material.
I have improved on these results by adding additional materials and isolation implements.

Chipboard, is not a usual go to material, but it has merit for what it can do.
It has many densities available and is a great at eating external energies, as it is produced in various compressed states , it can be swapped out for other types and can be almost attenuated to suit a individual taste.

To produce the base,
I couple the Chipboard to the floor on spikes.
I put my Granite flat onto the Chipboard, I start out with no isolation separation devices.
I then put the Speakers onto the Granite and have a listen, I will use a variety of devices to isolate the Speakers from the Granite, from Cork, to Foam and Rubber, and then Spikes direct or spikes into a receptor base.
When this is as good as it can be on the ear, live with it for a period of time, and then see if there is a further benefit to be got, by using isolation devices of the same used materials between the Granite and Chipboard.

The above was the old way using available materials collected over many years.

Today, I would say, get a Slab of Granite or Chipboard on Spikes or both together if they are available as referred to in the above to be used as the base.
Here is the next requirement that has been developed from trialling different isolation devices on a range of speaker types.
Use dedicated Isolation Suspension Devices.
My experience started with the Solid Tech 'Feet of Silence' being re-purposed to a position under a lightish weight speaker, as well as Audio Technica AT-616 Pneumatic Footers.
They were set up under a individuals speakers who was close to purchasing Townsend Isolation for their speakers.
What was already a high quality presentation from a three way cabinet speaker with a dedicated base, was much improved with the addition of the suspension/isolation devices, and on the isolation devices removal,
it was very evident of the much improved SQ that was just being heard.
The individual bought the Townsend Products as the result.

At a later date a similar set up was placed under a Stand Mount Coaxial Horn Speaker, the owner of these is anal about detail retrieval, and had spent much time with his bases, where a sand box and African Black Wood was in use.
The Suspension/Isolation footers were sat directly onto a timber flooring, and to say the outcome was night and day, would be the best.
The Speakers owner has now built their own Suspension Bases using a platform that is suspended on O Rings, so there is a DIY option if a little thought goes into it.

Another option but not trialled by me but that is getting great feed back, is a method being carried out by a local group of HiFi enthusiasts, after hearing my 'Feet of Silence' under equipment there was a search put on to source a device that was much more affordable and comparitive in performance.
The group now believe this has been discovered, in the form of IsoAcoustics Pucks.
On hearing about the results that were being had under speakers with my devices, they Pucks were used under Quad ESL Speakers, the reports I have received are on par with my above reports on the improvements being detected.
IsoAcoustics have a range of devices, and there is a good used market as well,  to allow for a cheaper entry into any trialling if so wished.
The used market might also allow for the purchase to be comparative to the outlay required to produce a DIY version of a Suspension Device.

I hope this helps with your enquiry.               
 
  

twoleftears
1. Do Isoacoustics Gaias + cups isolate?

>>>>Yes

2. I didn’t say that. I said that via youtube and computer speakers that that was what the difference sounded like to me. I wasn’t in the room, nor, I suppose, were you.

>>>>>I don’t have to be in the room to appreciate how isolation affects the sound.

I concur granite is an excellent material, no doubt due to its inherent stiffness and mass (inertia). I have been using granite with my springs for isolation for more years than I care to remember, assuming I could remember. Ha ha Another excellent material is a slab of Bluestone, I.e., paving stone, a similar but less expensive choice. Available at many but not all Home Depot. The mass and stiffness of these slabs are just what the doctor ordered to push back against the bending forces 🔄 of seismic waves. The springs are rather good at dealing with vertical forces. 🔝

Ok Geoff I'm trying your idea of springs and a granite slab or 2. I would assume 2 stacked would be better. I'm going with nothing in between. I'm picking up the springs Monday. I will tinker with that. I will then see if the sorbethane between the slabs is a bust with the springs. Maybe skip that and go with the spikes. Thanks for your expertise here and thank everyone else for there sometimes passionate opinions.