@jhills +1 for the spikes into maple platform.
Between the maple and shelf I use a gel type material which gives me a floating platform.
Re: wood blocks. I used a ayer of cork under the Myrtle blocks. I still had the tight bass and open soundstage, but highs remained harsh. I think the vibration of the component passes to the wood, then back to the component chassis.
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@rixthetrick
Since you use springs extensively, would you provide a recommendation for sizing the capacity of the springs compared to the weight they will each support? I have some springs arriving today to try under my 70-pound amplifiers. The maximum capacity of the springs I ordered is slightly less than one-half of the weight they will each support. Are there pros and cons related to sizing them, i.e., stiffer or softer? |
@mitch2 I am going to make a generalization that may help. - 50% compression under load is a good area to be in relation to mass loading of the spring. However, taking into account the amplitude of vibrations so that the spring will not bottom out, which is when there is no play left for the spring to compress. Much like a pendulum there is a frequency relationship with the spring rate and height of the spring. So far I have like the most a 4" tall and >2" diameter spring that compresses slightly over 50% under load. Approx. 3.5 turns of working spring with ground ends to have a flat interface.
(please be aware with taller loads the center of gravity can more easily exceed the limits of the loads base, creating an unsafe situation. Moving the base out to compensate and having a unified structure ie. screw outriggers to the bottom of a floor stander speakers for example, possibly where the spikes screw in)
- If you have a spring that under load is at 50%, it would be advantageous to have the diameter to be at least the same if not more than the final loaded height of the spring, for the sakes of stability.
- The goal of sprung isolation is to remove as much as possible the energies in the substrate coming up through the rack or whatever is being used to hold it, primarily from the vibrations of the speakers and subs. Or to to limit the energies going into the substrate into other elements in the system.
- An interesting note about the video shared by camb, there is another very good way to absorb, or rather transform the energies that the electronic devices themselves create. Putting a suspended mass on top of the device, effectively sandwiching the device between springs and mass, can also be implemented with great success. For example a soft faced rigid sheet with springs or absorbant material, with a mass on top.
http://www.audiopolitan.com/blog/eti-amg-toppers-review/
- Remember that the springs themselves are going to be supported by a substrate, this is where perhaps spikes into concrete may help the most. Because the less yielding the material under the springs the more energy will be kept into the suspension system and the mass it's supporting. Hopefully the energy stored in the cabinet can also deflect the spring and make the cabinet more inert sounding as well.
There will be a point where the resonant frequency of the subsrate will allow certain frequencies through, hopefully with diminished amplitude. I recently had a conversation with another Agoner and suggested if he's happy with his speakers on springs with his peer and beam floors, that framing up directly from the ground under the locations of the speakers it may make it more rigid and thus improve isolation. This theory has not been tested yet.
I have only been doing this for four years now, I'm still learning, and learning a great deal from this forum. Mitch 2 - PM me if I can help? |
@mitch2
Experiment with a TMD Tuned Mass Damper on top of your equipment as well as sprung isolation, this could both isolate the vibrations emanating from the device into another, or from others into it. Whatever you use as a rack, remember it's holding the spring that is holding your amplifier, the energy will be absorbed by both the rack and the springs, please be aware of that. The more rigid the rack is, it's also sitting on your floor which is also going to absorb some energy, the higher percentage is isolated up into the springs. All the best mate! |
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