Author Topic: Coupling, Decoupling & Isolation, Anti Vibration, Shock Absorption  (Read 1332 times)

Offline ronildoq

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2019 was a fantastic year for me in audio and HT, I met many nice chaps along the way in the various demo sessions

I am still focused on improving the set up further, if I find any. I came across a company, in Singapore. Not so well known, called varititan. They specialise in hifi racks and isolation.

Recently I added on a 2 tier hifi rack. Haven’t had the time to assemble it



The tip of it, is round in shape, very good vibration isolation



Various heights



Quality is damn solid  for the price



Using 3cm wood material that can withstand 80kg, the wood material provides a warm signature to the end results



I’ll be adding on sorbothane material beneath the pucks, sorbothane is a type of silicon material mix that provides superb anti vibrational benefits, highly beneficial placing these underneath. These will go under the source equipment, Oppo and lyngdorf

The goal is to isolate any equipment in the chain that provides mechanical vibration .

The heights for the rack is chosen to fit the equipment height and sandwiched between two boards to further prevent airborne vibrations

Next I had 2 pieces of granite slabs right under the Monitor Audio GX300, beneath that granite slabs are sorbothane and cork material combined, cork from daiso



Granite slabs look like this above, except this is on for CD player. I will have it beneath the floor standing speakers

When the speakers are elevated, it will be perfect as the sofa is also elevated with crowsons actuator sitting under(addition soon)

If 2019 was the year for Low noise floor, 2020 will be the year of isolation & anti vibration. This I believe will benefit the set up to a certain extent , especially at my place that has laminated timber flooring

Lotsa organising again

Offline ronildoq

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ok, lets break down further, after the demo sessions, taking in feedbacks etc. Whilst demo was ongoing, I was seated at back observing. I notice there was tremendous amount of vibrational energy on the wooden floor at my place ( thank God no complains so far, good neighbours)

i see a lot of benefits with "Vibration isolation". There are two types in general, Structural Vibrations and Air borne vibrations. The area im working to improve on is, Structural vibration.

The first point that I noticed is that even with the speakers on spikes and carpet, the wooden floor still transfers these vibrations to the speakers. I haven’t yet experienced how much more improvement it will bring to the set up when the speakers are isolated effectively from the wooden floor.

From my understanding and conversations, I believe it will bring about a great deal of benefits. Here are the few benefits I think it will bring to the set up

1. Decoupling the speakers with the spikes beneath the speakers, isolates it from floor. Because energies moves both ways, From/to floor/speakers vice versa. the decoupling will help I believe, providing the necessary isolation

2. This also reduces noise transmitted through floor that will otherwise excite the entire wooden floor structure

3. Elevating the speakers. It helps since the sofa will be fitted with the crowsons, changing this height to match up to how it will match the height of ears at MLP. (Folks have experience and observed this effect on two different types of sofa, one three seater with higher resting area, another is single seater at lower position.

4. To effectively reduce speaker cabinets internal vibrations when the speakers recoil, by adding the seas woofers and pushing the XO to a higher point. Since the floor standers no longer need to handle lower frequencies, they should technically have lesser vibrations and sound cleaner

The question now for me, to find out, is how to effectively isolate and reduce as much vibration on the speakers and source equipment, ie lyngdorf and Oppo 205.

For the granite slabs that I got for $80, I plan to have cork material and sorbothane mix, stick on underneath

Can buy this at daiso, I have a few



And this from amazon, fit this under the granite slabs



Both have very good damping properties and are very effective anti vibration material.

I’ll try and assemble these today and share further information if I do hear more benefits with the isolation



Here is how the granite platform looks like, and the flooring

I strongly believe with an effective isolation solution in place, I will reap the benefits on this

I may even try and affix a few of this sorbothane material on to the speakers cabinets, since it’s all black anyway, and see how this vibrations can be controlled.

Let’s see.

In case u r wondering what is sorbothane, here is a video

<a href="http://www.youtube.com/v/FNwIc_RNOHs&fs=1" target="_blank" class="new_win">http://www.youtube.com/v/FNwIc_RNOHs&fs=1</a>

Offline ronildoq

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Understanding how to choose the correct sorbothane for the application plays a big role too , here and hope this helps those who have wooden flooring like mine

What is durometer?

<a href="http://www.youtube.com/v/zjRnVx1_c-s&fs=1" target="_blank" class="new_win">http://www.youtube.com/v/zjRnVx1_c-s&fs=1</a>


Calculating weight loads

<a href="http://www.youtube.com/v/EaivqJV290o&fs=1" target="_blank" class="new_win">http://www.youtube.com/v/EaivqJV290o&fs=1</a>

Offline ronildoq

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Ok spent my night DIY’ing, ok can proudly claim to have DIY experience now !

Took me 20mins to hook it up and assemble



Seller was kind to give me some cable lifters, has got cork beneath it as well. I’m not sure on the benefits of the cable lifters, as I cannot apprehend the physics behind.

Why is lifting up cables from the ground beneficial ? No idea , I’m guessing it’s to do with resonance. Anyway, that’s not my focus, the cables will all rest on the rack anyway, and that will be isolated



The thing that impressed me the most is the design, u can see why the pucks are fitted with sorbothane beneath it



Observe carefully how it is placed, like a black circle ring. High Duro, easily 80kg. The key point here is that when this material touches the wooden floor, not only does it firmly anchor the rack down with stability, it also provides damping effects converting vibration energy to heat. It also isolates the vibration from/to floor

The technique with coupling the rack works differently, it provides transference of energy to the rack. So this is the key difference, a very important one as all energy then moves upstream the entire rack.

The sorbothane material however, sits between the surface of the floor and the pucks, this works effectively to break up the transference of energy upstream the rack. Don’t underestimate this tiny black stuff, it is one of the key material here.

Spring and rubber makes good vibration isolation but poor dampeners

Oil dampers (dashpot) has got good dampening but poor isolation

Sorbothane with a mix of elastic material with liquid, has the benefits of both worlds. Something like a squishy silicon stuff. If u have heard of “Gu Jit Su” toys and feel their material, it’s something like that , if u throw it on the floor, it’s got almost zero vibration



Next look at the tip, the lesser the contact, the more the energy it requires to pass on any vibrations up to the platform above.

The choice for two tier is to ensure it doesn’t go past 55cm, ie the lowest limits on the PJ screen. This is to also Ensure that nothing sits in the middle and the stage is clear for a good stereo image. In short, best to de-clutter

This is the spec from the rack



The design makes sense to me

So there goes again, another round of Re-arranging the console rack and cables etc.

Let’s see again what further benefits it brings to the set up

Offline ronildoq

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i figured this warrants opening a thread by itself, probably not suitable on another thread. The discussion on coupling, isolation and decoupling can be huge. Its talked about everywhere.

Another here on the bass section for subwoofers. But its not just for subwoofers, it applies to source equipment, speakers, racks etc....

But in case you are interested to find out about coupling and decoupling on subwoofers, there is the link below

http://www.xtremeplace.com/yabbse/index.php?topic=284092.0

Offline ronildoq

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Coupling, Decoupling & Isolation, Anti Vibration, Shock Absorption
« Reply #5 on: January 10, 2020, 08:57 »
Ok now back to topic again, this is how I have arrived at using these sorbothanes

In using these sorbothanes, I have to first identify the weight behind the equipment. As usual, I pull up the excel spreadsheet



As u can see I have broken it down to various sizes in diameter, thickness, and durometer for my application .

The first on left TOP corner, is to have the sorbothane material beneath the spike ball bearing base that will sit on the granite slab for the speakers. To work out which material to get, I first identified the weight of the speakers

For the Monitor audio GX300, weight is 28kg. Since it will have 4 footers, it’s 7kg on each side. Next zoom in to the sheet specs for the right size surface area etc, the information is made available here


https://www.sorbothane.com/Data/Sites/31/pdfs/product-guides/Sorbothane-SPG.PDF

Now this is the crux of the entire isolation thing.

The diameter of 1.5” (3.8cm) for a circular type sorbothane is picked to sit right under the ball bearing base (see pics below) that is 4cm in diameter . I went with a durometer of 30 with a thickness of 0.25.



The surface of coverage should not be too big. It should be smaller than the base for it to be effective.Oversized isolators raise the natural frequency and reduce the effectiveness.

This begs the question on the varititan racks use of sorbothane footers on the choice for durometer, because the weight of the rack supports 80kg, a higher duro was required , that makes it stiffer. But from a consumer point, the equipment on the rack may only be 10kg. So a lower duro like 30 would be required instead. So the key lies in the total weight pressing it down

The sorbothane material works best when compressed, when it takes that squishy form, and that is when vibrational shock absorption is effective up to 94%

So the correct weight with correct material , surface area and thickness used plays a huge role here for it to be effective

I’ve worked out the numbers for the rest of the equipment in the spreadsheet and got it shipped directly from amazon, free shipping anyway being prime member

Offline ronildoq

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A lot of times, I hear this, Hiya, don’t need for surrounds la, just LCR is enough.

Ok here is my take, my personal view is why should the surrounds be compromised?

The mastering these days have tons of content in the surrounds and Atmos, maybe not as much as LCR, but they DO MAKE A DIFFERENCE in the overall experience for HT and 5.1 music listening

If u can have good speakers for your surrounds, why not ? Why should it be any different from your LCR? Don’t they deserve equal treatment to bring out the benefits ?

Just my view of course. Ideally if funds don’t permit, then one step at a time. I’m more in the camp of people who like to buy, and improve things or bring out the best in my investment, rather than changing gears around. ( unless absolutely beneficial and necessary)

My surround speakers are also floor standers, they stand on the wooden floor. Isolation here will definitely be beneficial in my view

Anyway, let’s see how it goes. The decoupling , coupling technique must be done correctly, very important

Offline ronildoq

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Next will be the sheet stock, these cost approximately $75 shipped to door step, from amazon directly again.

These sheets serve another purpose, to dampen airborne vibrations and work as vibration dampeners to the cabinets or chassis of the equipment, and u can cut them to size , and rest it on the equipment or cabinet, they absorb the vibrations and convert them to heat



The salient points

1) these sorbothane are good shock absorbers and has got very good damping properties

2) it’s versatile, flexible, non skid and last longer as in it doesn’t harden or crack over time

3) having a 1” thickness provides good vibration damping effect down to 10hz

4) It combines shock absorption, good memory, vibration isolation, in addition to damping characteristics


Some of these will sit on the Oppo 205 and Lyngdorf chasis, absorbing air borne shock vibrations from surrounding air pressure, a result from using multiple subwoofers with high SPLs

Some of these will also sit on the cabinets of the subwoofers and will be used in conjunction with bolting it on the wall when I build my new line source woofers.

6x 10” Seas L26roy woofers will be bolted to the wall/baffle wall. Will share actual pics when I have them ready, the plan for now is to have it like this pics below



These washers (pic below) will fit into the screws, to reduce any transference of energy to/from the baffle wall / wall. The purpose for bolting is to provide better recoil stability as the woofers are expected to be 2.2m tall when stacked. Stack stack stack !!



Work in progress now for year 2020! This year I’ll be working on decoupling, isolation, vibration damping... to further improve the set up, as I pursue to try and expand my knowledge and experience in HT

I’ll share my findings as well.


Offline Jag

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I second the sorborthane absorbers. I use them for me subwoofers and they are very effective in isolating vibrations from coupling to the structure. Aircon, washing machine, tactile transducers, subwoofers..... you get the hint.

I get all of mine from amazon. Sheets, blocks, semi-spheres, rings. Far more durable and effective than rubber or foam. It’s even used in space shuttles to minimise vibration transmissions.
Electronics : Denon 7200, MiniDSP Dirac 88A, Emotiva XPA-5 Gen2
ATMOS Audio : Martin Logan Ethos (L&R), ML Motif X(C), ML Motion 4 (14pcs surround spkrs)
LFE : Dual Rythmik FV25HP & Crowson Motion Actuator
Video : Sony VPL-HW55ES, Stewart Screen Studiotek 1.3
Source : HTPC
Fully automated HT via Alexa, Z-wave and Logitech Harmony Remote Control

Offline ronildoq

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I second the sorborthane absorbers. I use them for me subwoofers and they are very effective in isolating vibrations from coupling to the structure. Aircon, washing machine, tactile transducers, subwoofers..... you get the hint.

I get all of mine from amazon. Sheets, blocks, semi-spheres, rings. Far more durable and effective than rubber or foam. It’s even used in space shuttles to minimise vibration transmissions.

Oh u are also using this ! Fantastic then , I just read about it. Apparently NASA uses it too. I think for the price and effectiveness of it , quite hard to beat

Just saw another video on isolation ( not sure how to embed the FB video), simple to understand the benefits , all down to physics. Nowadays it’s so much easier to apprehend with videos

https://www.facebook.com/812929935766088/posts/1073417843050628/

Yes I also just noticed that the crowsons actuators uses sorbothane !


Offline ronildoq

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Ok some of the stuff just arrived



Getting things organised and ready, hopefully in time before cny

I wanna share this very informative video, I hope u pick up a thing or two from this fantastic video, by norman .


<a href="http://www.youtube.com/v/6G4HF6wJG38&fs=1" target="_blank" class="new_win">http://www.youtube.com/v/6G4HF6wJG38&fs=1</a>

One of the well respected guys. here are some other information obtained from FB, by Norman as well



Zoom in to 12 mins in the video or so where he talks about density and how the denser the material, the faster the sound travels and reaches you

That’s precisely the reason why I don’t go nearfield subwoofer placement, exactly the same feeling, see he quoted railway road as an example, I quoted mrt in the subwoofer section

Glad Wechnivag shared this video today, thanks again bro.

I see the huge benefits with isolation stuff, as u can see from the video above, it is quite clear how it will help improve our system


pS:/ Bro Keai, headsup here on why I recommended delaying the crowsons by 0.5ms to 1ms, the reason is here!! Because the denser the material,(your floor), the faster the sound/vibrational energy hits u, faster than the subwoofer air pressure, when that happens, it takes away the feeling of the air pressure from the subwoofers. The key is timing here, the crowsons work to complement the subwoofer, not to be the subwoofer...check out the video man!

Offline Jag

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Ronildoq, I’m glad someone actually is able to differentiate  decoupling and coupling. But most audiophiles only believe in spikes for everything; from equipment to speakers to subs. There is a lot of science and physics behind this and I’m Glad you are expanding your knowledge on the multiple facets of HT.

At different situations, decoupling vibrations may be more important than coupling strongly to the ground. In my current setup to minimise neighbourly disturbance via vibrations, I have used sorbothane widely to tame vibrations from travelling to the neighbours.
Electronics : Denon 7200, MiniDSP Dirac 88A, Emotiva XPA-5 Gen2
ATMOS Audio : Martin Logan Ethos (L&R), ML Motif X(C), ML Motion 4 (14pcs surround spkrs)
LFE : Dual Rythmik FV25HP & Crowson Motion Actuator
Video : Sony VPL-HW55ES, Stewart Screen Studiotek 1.3
Source : HTPC
Fully automated HT via Alexa, Z-wave and Logitech Harmony Remote Control

Offline Jag

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PS: I run a lab in my work and use this very often for isolating high magnification microscopes from structural vibrations.

The good rule of thumb indication the sorbothane is used optimally is when the sorbothane material is compressed by ~50% with the load on it. Or anything between 30 to 60% compressed. Anything out of this compression, the absorbing effect gets reduced.
Electronics : Denon 7200, MiniDSP Dirac 88A, Emotiva XPA-5 Gen2
ATMOS Audio : Martin Logan Ethos (L&R), ML Motif X(C), ML Motion 4 (14pcs surround spkrs)
LFE : Dual Rythmik FV25HP & Crowson Motion Actuator
Video : Sony VPL-HW55ES, Stewart Screen Studiotek 1.3
Source : HTPC
Fully automated HT via Alexa, Z-wave and Logitech Harmony Remote Control

Offline joamonte

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Bro regarding coupling and decoupling of speaker , there are 2 school of thought.

Yes decoupling reduce structure borne, reduce the sound transmit to room floor wall ceiling surface, hence we hear more of the speaker sound....

But at the same time, it reduce the effectiveness of the loudness of the speaker , the speaker/sub will need more watt to achieve the same loudness as compare to coupling the speaker to a dense surface, the amp will and woofer will need to produce more SPL by itself hence electronic and Mechanical distortion also increased.

Choosing a correct coupling surface is tricking , concrete and wood all have different resonance response hence depend what the sound of the system lacking , sometime correctly choose the coupling surface give better sound than decoupling all.

Just my 2 cents worth 😊

Offline Saycheese78

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Well said joamonte, well said. What do you think of iso acoustic? They claim to couple and concurrently decouple!