REL Subwoofer Iso Bones

Over the years I have experimented with various speaker supports that isolate/decouple the speakers from the floor. To me these techniques provide a bit more clarity possibly due to removal of some coloration that may be attributed to the speaker cabinets being coupled to a large mass, like a floor structure. My latest iteration is for a pair of REL S3 subs. The bones are made of Maple boards glued together with three holes cut in them to tightly hold three hand balls. The whole assembly is fastened to the existing m8 threaded holes located on the feet of the REL S3 subs. Three balls provide the proper amount of compession for the best isolation from the floor. These really improve the clarity of the bass. The decoupling seems to impove the tone of the bass. My floors are concrete hollow core slabs.


Very creative…hope it works for you… Are there any concerns about the larger foot interfering with the LF “wave propagation” for lack of a better term?

I would think a footer on the scale of a few feet might, but when you look at the hand balls used which are ~ equal to the size of the existing L shaped REL feet I can’t imagine they would have any effect. Although the bones are made of 3" wide maple I would guess these too have little to no effect on such a low frequency wave. The bones are basically at the same depth as the floor would be at without using spikes and using the bones it’s within the range of the spikes height.

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I want to buy a per of REL S/3s for my basement office. The floor is solid poured concrete, so are the walls. I haven’t given any thought to set up, other than corner placement along a 17 wall on UNcovered floor. i am thinking wireless. A future wood floor covering may or may not happen. 35 yr. old Klipsch Forte speakers now, but the subs are prep for PSA speakers. My goal is clear, tight bass to complement the speakers.
I would greatly appreciate any comments, suggestions regarding the S/3 setup.

Check out the REL website. They have some pretty specific suggestions for best placement for their kit.

Chances are, if you experiment with the options they provide, you will be satisfied with performance. Based on personal experience, don’t be afraid to experiment with getting those subs out of the corners. See here, for example: REL Placement Guide.

Have fun.


I actually found my REL’s better hard coupled to heavy marble blocks. I also have 100# of weights on top of each one. So I found direct coupling is better not isolation. Just as REL recommends. YMMV of course. Yours certainly took much more effort on your part!

I found this info of some interest, it describes my findings when using the ISO Bones…

SVS SoundPath Subwoofer Isolation System

The SVS SoundPath Subwoofer Isolation System works with nearly every subwoofer brand and model to improve bass performance while reducing floor and wall vibrations, noise artifacts and complaints from neighbors or roommates. De-coupling a subwoofer from the floor results in inherently tighter and cleaner sounding bass.

How Does De-coupling Improve Performance?

Decoupling is making the interaction between a subwoofer and floor so weak that virtually no energy is transferred between them. The SVS SoundPath Subwoofer Isolation System features rigorously tested optimized durometer elastomer feet that significantly reduces the transmission of subwoofer energy through your floor and walls. This allows low frequency effects to be transferred through the air where they can be felt, resulting in tighter and cleaner sounding bass, no more distracting buzz or rattle from the room, and better sonic clarity and dynamics

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Yes - they work very well; @scotte1uses them and he likes them. I used them for a while and moved to GIAIII for my REL S3/SHO. REL would say there is no advantage and blue tack works as good… I like all three and have tried all three… however, have not tried 100lbs of weight on top of the REL subs w/ blue tack… interesting… since my REL S3/SHO weighs ~65lbs, I might do that to test the direct coupling hypothesis… good idea… 100lbs is a lot of weight… maybe a (2) 45lb plates & (1) 10lb plate stacked with blue tack between each plate to stop them from sliding off the sub when playing some serious bass passages… interesting…

SVS Soundpath Subwoofer Isolation System

Now we are talking - need to get spray painted black with some blue tack securing them…

I like these better, they seem to interlock and 90lbs should be enough

I used to keep a 45kgs plate as pictured above for many years on top of my Vandersteen sub that would jump around when driven (happily) very hard

Isolation or de-coupling vs coupling in my experience matters what kind of floor the sub is on. Concrete slab, try both and chose based on sound, raised wood floor - no question isolation improves performance by reducing the ‘sprung’ floor resonance.


In my “little” system I have a old REL Q108 MK II. Underneath is padded carpet flooring on standard subfloor. Then 1/2" thick Granite slab overhangs sub 1.5" on all sides. Stock REL feet, not spikes are on 2" thick by 4" square sorbothane “pads”. On top of the sub is 50# of gym weights as OP shows here. It sounds outstanding to me with REL “BLUE” cable in place. Is there anything I could have done better? It actually reaches to 12HZ at -10HZ in room! It has a “wavy” glass panel behind it, where it is locked 6" into a 3 way corner. integrates seamlessly. Xover is on 36HZ with very high end bookshelves, and volume is 1/4. no, it does not slam but the bass extension is plenty adequate. Just wondering about “better” isolation for it? I am afraid to raise the driver too far off the ground though? Perhaps remove the stock “feet” to put bigger aftermarket feet/ I am not so concerned about the cost of anything. just the best sound I can obtain. after extensive research years ago and today, this is the largest sub that will fit that corner and still offers a good degree of musicality. this is not like the REL Zero made in china now. this is a true Richard Lord ERa sub and had a original MSRP of $1,999.00 for an 8" sub! I am 100% happy with this and fully intend to keep it. I am just wondering if I could do a better job of isolating it. This, since I now agree with you that the smaller ones are better off isolated indeed! the very large ones probably fare better direct coupled in my larger systems however. I hope anyone is still looking at this now quite old post! thank you!

If they are compatible (“attachabitlity-wise”), give those SVS “Soundpath” footers a try. They are reasonably priced and impactful. But you need to listen to see if you like them as applied. For instance, I use them on my REL Acoustics T/5i subwoofer in my office system to good effect. I did not like them as footers under my Anthony Gallo Acoustics Reference 3.1 speakers however – they seemed to make the whole presentation a big foggier (with the Gallos, that is) IIRC.

Have fun with it.

I’ve been using very large cork bungs as isolation feet - 1.50 each on eBay 65mm and around 35 mm deep. Make a definite contribution on my main speakers :slight_smile:


I’ve been using Isoacoustic isolation on my speakers and subs for a couple of years now. My system sits on a wood floor, and, sounds way better isolated vs coupling.

@kylemillsap - My REL S3 subs sit on wood floors, using GIA III feet and they sound amazing isolated versus coupled. Brett’s comment above is spot on.

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I was always of the thinking they should be “coupled”. as, usual REL is different! they do best isolated! I will either get GIA III Or I have some unused still Points ultra 6 which is a shame given their price. However with these subs I think it is imperative that the footers must be screwed into the sub itself? It cannot just be “resting” on them? though, in essence that alone should cause for further isolation. I will just have to listen then. Also, as I mentioned, I am pretty sure that for anything down-firing the driver needs to be exactly the distance off the ‘substrate’ as the designer intended?

I have faired best with the granite on this after many trial materials. Under the Granite is a 'Spyderweb type suspension" before the carpet. So now it will be 100% isolated from the building structure, other than pressure loading.

I am glad you folks added to this, being this old. Since I really need to revisit at least the little system. It does not punch me in the gut but it is plenty adequate for 2 channel. 2.1 to be exact :slight_smile: For it’s size it goes lower than anything made today. To me it is not going anywhere in this room anytime soon!

I most certainly need to ‘tweak’ it some more at this venture. now, seems as good a time as any to me! I am not one to put the ultimate sound on hold for very long. I am actually surprised at myself that I have neglected to explore this further thus far, however it will be starting tonight! the big thing here is I am not sure if the footers must absolutely be screwed into the REL itself? that, will perhaps open an entirely different realm of possibilities given the answer? thank all of you!

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I am no expert, but my assumption is that the distance to the floor is only material w/ regard to the driver being too close.

As long as your aftermarket “feet” are at least as tall as the OEM kit, you should be fine.

My $0.02.

Could they be taller, or will that diminish the bass frequencies?thanks

Sorry, that was the point I was trying to make…that equal to or taller should be fine; but shorter MIGHT be an issue. Fiddle around and let your ears decide?


Perhaps not
to other subs, hearing the Auralex SUBDUDE as simple as it is, provides adequate isolation to this little thing. I figured I would take it a step further and just “sand box” it with a very dense artificial ceramic sand. Although I I imagine if the driver is simply “too” high from the, substrate some point bass will be lacking and eventually vanish altogether. Of course we are talking within reason not 3’ footers here. Or at least it then becomes "infinite “baffle” and no longer a loaded box.

The improvement overnight was substantial to my ears. Not. sure why I did not think of this sooner. other than building the sandbox took 4 hours of my time. It is furniture grade, not a slop job. I will not know now, but I figure this worked out to more “dead” sound than footers or rather isolation/decoupling could possibly provide under any circumstances.

Other than air pressure loading, it is 100% mechanically isolated from the building structure now AFAIK. It made a big difference to something already outstanding IMO. Of course this would not be practical with a 250 pound plus subwoofer. Which is why, obviously other options exist in the marketplace for such larger boxes. Right now however this was already reaching to 12hz@–10B in room and I have already measured 8HZ as of yet!

If you think about it, this defies science for a sealed 9" box I am quite pleased with it and shall never part ways with it for something else unless I should happen to come across much more room. the room exists, it is just in use by other furniture. It has always been that way, fortunately. however this little guy leaves me wanting for nothing short of using it for HT which I do not, ever. this upgrade last evening was just the icing on the cake. I am not sure what prompted me to undertake this project now, but is was absolutely worth it! I am extremely pleased with the outcome. now I just have to wonder if the footers would have beenbetter! although I see sandboxes such as this one here going for $3,500USD!

I just wonder if the original OP was onto something with the softer Squash balls? the sand is plenty pliable but it’s top and bottom plates are solid Maple. On top of that rests a 1/2" thick slab of granite to “slot load” the driver’. there is much more “mass” to my setup, but the OP placed #100on top of their REL as well. these do need to be fortified. At least in some manner, if not in many ways more than one. so that is my finished product, in more than a few words. I hope this gives someone inspiration!

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I have a down-firing sub. I got an acrylic off-cut from a local guy for about $10 and it sits on $2 of acoustic foam. Job done, neat and tidy.

The thing is plenty heavy, but has a 20kg bronze sculpture on top of it.


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