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Loudspeaker isolation ...

Purité Audio

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#1
Could you imagine a scenario where isolating loudspeakers could be really beneficial to SQ.
Say a suspended floor which audibly resonates because of the structural borne vibration propagated from the loudspeakers.
How would the airborne vibration compare to the structural , any links to research would be useful.
A few years back a very nice chap from Speirs&Robertson came to measure my ( suspended) floor with a three plane accelerometer, even with the speakers playing bass heavy music, very loudly there wasn’t that much vibration .
Interested as always to hear your thoughts.
Keith
 

jtwrace

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#2
 

RayDunzl

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#4
Concrete slab floors and no seismic activity here..

You want a sandbox for isolation?

My whole house sits on one.
 

andymok

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#5
imagine it's violin/viola/cello/bass
strings are your loudspeaker
feet are sound post

why the same set of strings never sound the same?

just a quick analogy i could think of, please enlighten me if I'm wrong
 
Last edited:

Ron Texas

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#6
My third floor music room really shakes around 31hz. It's the floor, not a typical acoustic room bump. Not louder, just shakes. It does wonders...
 

flipflop

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#7
My third floor music room really shakes around 31hz. It's the floor, not a typical acoustic room bump. Not louder, just shakes. It does wonders...
31 Hz is oddly specific. Maybe it could be fixed with a high Q notch filter.
 

Ron Texas

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#8
31 Hz is oddly specific. Maybe it could be fixed with a high Q notch filter.
It can be fixed by moving the sub, or changing it from down firing to front firing. I kind of like it because it doesn't get louder, the floor just vibrates with it. In one scene an actress was pounding on a piece of glass. I thought the TV was going to crack. It's that cool.
 

svart-hvitt

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#9
It can be fixed by moving the sub, or changing it from down firing to front firing. I kind of like it because it doesn't get louder, the floor just vibrates with it. In one scene an actress was pounding on a piece of glass. I thought the TV was going to crack. It's that cool.
There’s no right or wrong if you simply like it!:)
 
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#16
The best solution I've found is this http://www.sonicdesign.se/sdfot.html - super bad website but the product can be found at retailers. Backed up my measurements and no bs. You buy them according to the weight of your speakers, subwoofers, electronic etc. at places like https://www.snyggtljud.se/sonic-design-sd-dampkuddar-for-hogtalare

Anyone who has looked into this sort of thing will find that spikes are useless if you want to isolate vibrations - they instead connect the speaker to the surface. Yet all "audiophiles" swear by spikes.

All in all it probably makes a minor difference but it should make you hear less of the room or more of only the speaker if you will.
 
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#17
The best solution I've found is this http://www.sonicdesign.se/sdfot.html - super bad website but the product can be found at retailers. Backed up my measurements and no bs. You buy them according to the weight of your speakers, subwoofers, electronic etc. at places like https://www.snyggtljud.se/sonic-design-sd-dampkuddar-for-hogtalare

Anyone who has looked into this sort of thing will find that spikes are useless if you want to isolate vibrations - they instead connect the speaker to the surface. Yet all "audiophiles" swear by spikes.

All in all it probably makes a minor difference but it should make you hear less of the room or more of only the speaker if you will.
They look like they may be Sorbothane hemispheres, which match your description and can be bought more widely. As you say, it's important to get the right type/size/number for the weight of the item to be placed on them.

I have some Sorbothane hemispheres but when I compared with/without acoustic measurements of my main speakers I couldn't see any meaningful difference. I now have a sub, the walls of which vibrate far more than my main speakers so I was actually contemplating a test with this.
 
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#18
I have my bookshelfs on cabinets. Put a cork yoga block underneath the speakers and that stopped the cabinets from resonating. Did wonders for SQ.
 
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#19
They look like they may be Sorbothane hemispheres, which match your description and can be bought more widely. As you say, it's important to get the right type/size/number for the weight of the item to be placed on them.

I have some Sorbothane hemispheres but when I compared with/without acoustic measurements of my main speakers I couldn't see any meaningful difference. I now have a sub, the walls of which vibrate far more than my main speakers so I was actually contemplating a test with this.
Well they are not Sorbothane hemispheres but they might work on the same principle which should give the correct/same results. Usually however I find that most of these types of products are too hard and don't actually absorb the vibrations but transfer them. Like you said it's very important to have the right tool for the job - in this case a foam/rubber that's made for a specific weight span. I can't see them advertising different weight spans for the Sorbothanes. Maybe I just didn't look hard enough.

With really well made speaker cabinets vibrations from the cabinets will basically be a non issue but it does go both ways so if the floor is vibrating from multiple 18" subs in the room or whatever it won't transfer to the other stuff standing on the floor. Should be useful if you have electronics in the same room as a really powerful speaker system as well. In my case I have the electronics outside my listening room so a non variable there.
 
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#20
Well they are not Sorbothane hemispheres but they might work on the same principle which should give the correct/same results. Usually however I find that most of these types of products are too hard and don't actually absorb the vibrations but transfer them. Like you said it's very important to have the right tool for the job - in this case a foam/rubber that's made for a specific weight span. I can't see them advertising different weight spans for the Sorbothanes. Maybe I just didn't look hard enough.
If they aren't Sorbothane I'd personally avoid them and buy the genuine product, which is also likely to be cheaper.

Here is a Sorbothane product guide which gives details of the correct weight range for their products:

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

As you correctly say, a lot of things that look like Sorbothane, aren't, and don't perform the same. It's not just any sort of rubbery material...
 
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