A definite sonic improvement in tightening up the bass. 1. Start with 4 aluminum cones. I used some old Mod Squad Tip Toes. 2. 16x16 slab of granite. 3. 1/8 cork. 4. 1/2 inch neoprene rubber. 5. 1/8 cork. 6. Top with another 16x16 slab of granite. 7. Enclosed with a wood cradle to hide the mechanism. The granite is from scraps from a shop and was cheap. The added 1/4 inch of neoprene to 1/2 inch thickness did help. Let me hear your thoughts.
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:
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.
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.
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.
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.
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.
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.
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.
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
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.
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! 🤗
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.
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.
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.
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.
@audiozenology, the only rubber I use for isolation is a set of Sims Navcom Silencers in place of the stock springs in my VPI HW-19 Mk.3 turntable, a favorite mod amongst HW-19 owners. While the stock springs provide the well-known isolation inherent in suspended subchassis tables, they allow a fair amount of relative motion between the subchassis (containing the platter and arm/cartridge) and the base-mounted motor.
The EAR Isodamp I use is not the constrained-layer damping model (C-1002), but the version made for the damping of vibrating/ringing metal panels and chassis (SD125). It is a heavy (about 1lb. per square foot), dense, stiff, 1/8" thick material with adhesive on one side. Applied to the metal chassis of hi-fi electronics, it is very effective at absorbing and dissipating their ringing resonances. Unless you consider electronics to be musical instruments---a silly notion imo---and should therefore be allowed to ring away, a very effective solution for eliminating unwanted resonances. While my phono amp, linestage, and power amps benefit from SD125, my very robustly built Esoteric digital player has no need for it---that 47 lb. box is very well self-damped. I guess I can't be a card-carrying member of the low-mass-is-a-gas gang, ay? ;-)
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.
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.
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%.
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.
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.
geoffkait"I agree cork is a wonderful audiophile material"
I think that the reason many people reject, undervalue, or discount cork is that it is not a engineered man made material so for those who like to read, analyze, and assess product information sheets it does not offer the same satisfaction. However for those who actually have "real world" experience which means doing, testing, and listening and not just reading and "calculating" it can be very useful, effective, and advantageous.
Wood floor. Assume somewhat springy? ... then usually better to isolate.
Neoprene rubber of that surface area likely provides next to no isolation in the bass frequencies, and probably not much absorption. It is too stiff.
I expect the cork does not provide much isolation / absorption either. You have a large surface area and relatively low weight per surface area. That impacts the spring constant. Too stiff and you don’t isolate bass frequencies. You can get at least a bit of an idea by looking at how much it compresses when the speaker is on top. If it looks like it compresses little, then assume not much bass isolation. The problem with cork is to compress it enough to get a good spring constant for isolation, you will get to the point where cell walls collapse. w.r.t. Sound, cork is normally used for insulation, not absorption. It does not have the hysteretic losses needed for absorption unless used right in its sweet spot where it is quite good. Problem is ensuring you are using it properly.
The big granite pieces may be better transferring energy into the stiff joists of the floor. Added bracing under the floor where the speakers are can help too.
Replacing the cork/neoprene with well chosen sorbothane pucks/squares will be quite a bit better. Need to take into account speaker/platform weight, sorbothane type, and surface area. Thicker will provide more dampening. Let me know the weight of your speakers and I can give you some direction on the hardness / surface area of Sorbothane to use.
Springs will provide more isolation, but again, they must be carefully selected to get the frequency below the audible region.
Best would be a combo of springs and sorbothane to both isolate, and then damp speaker motion. Best of both worlds.
I agree cork is a wonderful audiophile material, I use pure natural cork for my Quark! product for damping capacitors, printed circuit boards and transformers. I eschew the composite glued up stuff which is probably what people are mostly using, assuming anyone is using cork which they probably aren’t.
audiozenology"I expect the cork does not provide much isolation / absorption either.
I expect the cork does not provide much isolation / absorption either.
Cork is an excellent isolator and one thing you should explore, study, and research is that it is possible to "over damp" the components in a Music Reproduction System there is a lot of research on this.
audiozenology"Clearthink, I am not going to stand for your continued, however veiled, personal attacks on me, as well as your literal stalking of me.You appear to engage near exclusively with me as evidenced by 23 of the 30 posts you made in 2 weeks being directly to me"
You do not seem to understand that everyone is free to contribute hear within the rules, policies, and standards of this group as set forth by the moderators and that means that those who may disagree with you or who wish to correct you’re errors, misunderstandings, or misstatements are free to do so and I am sorry if this has hurt you’re feelings as appears to be the case. Of course you are free to contact the moderators but you are not free to limit, restrict, or discourage me or others from contributing and you are not free to threaten me or others in any way whatsoever.
There are things you seem to struggle to understand such as induction and isolation in particular and these things are not always intuitive so there is no need for you to be defensive about this topics.
So my original design is sound? No pun intended. To get a tight grip on the woofer? Without the floor trying to affect it? To spike or not to spike? So sorbethane is out and my neoprene and cork sandwich stays? Or a spring sandwich with springs underneath too? Just curious does anyone here have a physics degree. I can hear positive results with my stand. I don't want to start a war with oral howitzers pointed at each other. I'm not trying to brush away any ones opinions. I wish everyone could come to a consensus. Lets have a vote. Without the why's please. 1. Sorbethane 2. Springs 3. Mapleshade device 4. Dedicated supports from my video of the RMAF 5. My device 6. Other. Explain?
audiozenology"Your attempts to try to discredit me, embarrass me, or whatever it is you are trying to accomplish are not going to work as that would require the knowledge to know who is and is not technically "up" on the topic. "
Stop it I mean stop it right now. You have been stalking me and I am not going to tolerate you're abuse. I will post hear as ii see fit without you're attacks and interference.
I am not confused, but someone reading a post mentioning lead and sorbothane in the same sentence like they are directly related may be. I don’t need to hide behind hand-waving explanations and insults on topics I engage in.
Lead can be a very effective sound absorber. That is simply fact. It is regularly used in this application due to density and hysteretic loss. It’s hysteretic loss is also such that it is difficult to make a resonant structure out of it. Like anything else, it has to be used properly.
Unlike lead, sorbothane behaves both as a spring (isolator) and absorber (dampener). Think of that like a combination of the spring and the shock absorber in a car (or truck).
Placing lead between your speaker and the floor could only provide some level of dampening. At bass frequencies, that would be almost none. Contrast that with sorbothane, which provides isolation by acting as a spring, and dampening. Properly implemented, not just buying some random things off the web, you can isolate something to <20Hz, and even <10Hz.
Your attempts to try to discredit me, embarrass me, or whatever it is you are trying to accomplish are not going to work as that would require the knowledge to know who is and is not technically "up" on the topic.
audiozenology"That someone would compare Lead to Sorbathane, i.e. a soft metal to a visco-elastic polymer makes me really question what message they are trying to communicate"
I do not understand why it is that you "question the message" perhaps you are confused that both are potential isolation materials with differing traits, characteristics, and qualities. It is rather like a truck and a car they are of course completely different in form, function, and use, but both are motorized transportation.
'That there is something you struggle to comprehend, understand, or apply does not mean others are being dishonest or deceptive to you.
I repeat - you can’t see the forest for the trees. I already explained it to you. You’re obsessed with challenging me. This conversation can serve no purpose any more.
That someone would compare Lead to Sorbathane, i.e. a soft metal to a visco-elastic polymer makes me really question what message they are trying to communicate. Lead would be more an analog to granite, SONEX an analog to a GIK acoustic panel.
To experiment properly with Sorbothane, one has to properly implement it, which means using the correct hardness material as well as the correct cross-sectional area for the weight being supported, no different from a spring. Unfortunately, people just say "Sorbathane" or spring, without the required knowledge to properly implement and hence they lead people astray.
SONEX is an acoustic foam, so not sure why you are bringing that into the equation ..... however, just like Sorbothane or a spring, it must be properly implemented to work well.
Sorbothane is one of the worst materials ever foisted on naive and gullible audiophiles. I put Sorbothane in the same category as SONEX and lead. Sorbothane is just another pretender. There are many black semi-soft viscoelastic materials that audiophiles have used for resonance control. Sorbothane is actually on the bottom of the list of ones I’ve experimented with. Sorbothane seems like such a good material, not too soft, not too hard. Little bit why audiophiles think lead is a good damping material. LOL
People would be far off in the long run 🏃♂️if they follow my suggestion of mass-on-spring isolation for their isolation needs and look around for an effective viscoelastic material for their constrained layer damping materials. It’s far better to leave things undamped than to over-dump in the great word of Acoustic Revive.
Sorbothane® combines shock absorption, good memory, vibration isolation and vibration damping characteristics.
Sorbothane® can absorb over 50 percent of vibration energy over most of its temperature operating range at frequencies from 10 to 30,000 hertz.
From me: Sorbothane acts as both a shock absorber and a spring. That is one of the reasons why it is effective. The problem that may arise with Sorbothane alone is getting the resonant frequency. Best to use their calculator and you may need to cut pieces to the size you need and pay attention to the Shore hardness. A very approximate rule of thumb is if the Sorbothane is compressed 30-50% you are getting pretty good isolation (~90%). 50% compression should put you under 10Hz resonant frequency.
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