To Couple or Decouple Bookshelf Speakers to Stands?

Just bought my first pair of bookshelf speakers (Focal Aria 906) and stands - have filled the stands with sand. Should I use sorbothane pads to decouple the Focals OR Bluetack them to the top base of the stands?  I've asked 3 friends and received 3 different answers.......
No to decoupling! The added weight of the stands will give a firmer foundation for bass response. Just like adding mass to the speaker cabinets.
Post removed 
If the stand is full of sand, it is decoupled. The term refers to bass to room coupling. The floor (normally). You have sand filled stands? I’d doubt that any bass harmonics are transferring down the stand. If you want to tune the bass (increase) you "beard" the front of the stands. By increasing baffle width and height it can be, a nice sonic nugget. Takes a bit of tinkering though...You’ll get it.. Even cardboard will let you work out the W x H. Convex, Concave, Flat, or split baffle...


I have done all the experiments. The best I have found is: fill your stand with a filler material, I use small pebbles (buy by the bag at Home Depot or Lowes) not as messy as sand. If your stand has spikes use Herbies  Cone/Spike Decoupling Gliders under the points. Between the speakers and the stand use Herbies Thin Fat Dots.

Try not to listen too much to  roberjerman and experiment.
If the question is to either couple of decouple, how did you receive 3 different answers??!
I use Blu-Tack between the speakers and the stands with spikes on bottom of the stands. Have hardwood floors over slab, so I use spike shoes to protect the wood. 
" If the question is to either couple of decouple, how did you receive 3 different answers??!"

Don't see 3 different answers. Mine was decouple, reached by trying all options and choosing what I thought was best. Opinion based on experience and experimentation. 
One answer was to couple with Blue-tack - the second was to use Sorbothane to isolate the speakers and the third (and the most confusing) was to use a combination of the two. As I said, this is one of those questions everyone seems to have a strong opinion on. The stands are filled with sand, they have spikes with rubber shoes to protect the floor. I'm going the Blue-Tack route to begin - it makes the most sense to me.  I'll post results. 
Blu-Tak is the cheapest, but not the best. Please do not use Sorbothane, it sucks the life out of everything audio, only  to be used as shoe insoles. Herbies is not cheap, but are the best IMO.
You get a lot of answers because there is no such thing as decoupling. There is only vibration control. This being the case every bookshelf/speaker combination vibrates differently and so there is no one universal answer. If decoupling was a thing then it would always work. So you can be sure its not a thing.

Coupling usually works, because mass is one of the easiest ways of controlling vibration. This is also why sand boxes and massive stands tend to work so well. You could even sandwich a speaker between two books, a thin one under and a thick heavy one on top. Not saying this will be great, but it is something cheap and easy you can try just to see what I mean. Ultimately it all comes down to trying a few things and going with whatever works best in your situation.

4,901 posts06-21-2020 9:13pm

You get a lot of answers because there is no such thing as decoupling.

Really? Coupling / decoupling, refers to harmonics, thus adding to the ROOM vibration, not the speaker. To decouple from a shaky wooden structure is almost always better. If you have a tip up structure, (all concrete except the lid), that is different again.

Vibration control, and coupling / decoupling are different things.
YET one laps into the other. Walking across a room, or simi going by, the floor shaking, is different than a speaker introducing bass harmonics. Both shake, both vibrate, both are bad, but they are not the same.

You say there is no such thing, then you explain how to decouple the speaker, with books. (partially). I guess that’s when it’s not a thing.

As you explained, there are degrees. It is true (the third answer from OP), the speaker may be PARTIALLY, coupled. So the answer is to add weight, and try to couple it. CHEAP BOX.. OK.. Thick boxes are never an issue.. MDF or HDF. That weight will couple to a room, and shake it....

I decouple completely, I don’t use the bass system at all in any of my monitors...and use decoupling mat. Silicone is always the best, there is nothing better, for the money....

I say if the cabinet is thick enough, (built right to begin with) I don’t need to kill the harmonics by adding weight, It’s already dead.. If a dead cabinet, is coupled to a DEAD stick, (the stand with sand), then it CAN’T be coupled to the floor.. THINK...One way to tell for sure, an accelerometer.

The tap test will tell the story.. does the stand sound like green concrete, NO NOISE.. If it does..Your already decoupled, like I said.. Add all the sticky stuff you can find....It’s already decoupled..Why would you want to
ADD vibration to a room...????? By coupling it.. Unless your on concrete, I still decouple...

In a book shelf, it’s alway the same thing, bass verses, Imaging. Coupling and decoupling is just not an issue with them.. Can’t be. The lack of a wide baffle and a very short one to boot, there just can’t be heart pounding bass, midbass yes. 60-80 hz if your real lucky. More like 80-100 is the lowest they will measure. If you want more bass add a beard. If you don’t like that. Gatling gun a bass system.. DBA..LOL

The reason why so many of floor sanders baffle are narrow NOW. They Image better but they lack in bass response. Answer, add a bass driver to the side of the structure. Problem, cabinet wobble.
Answer, separate cabinets, COLUMNS...Nothing better...

Decouple, if for no other reason that it measures much better. At least with most loudspeakers.

For example soft rubber pads/foam will decouple more than hard ones, but both will decouple hundreds of times better than wood on metal.

Just how far you need to decouple is best judged by listening. One good indication could be how well the bass is playing notes after some decoupling.

It's also quite possible that with some well designed loudspeakers that no decoupling is required. The designer may already have factored in baffle resonance control. Eg Harbeth, Linkwitz, Eclipse TD series, Magico, Wilson etc.

Hence the differing answers.
Always decouple. Don’t listen to 4H clubbers. 🐄 🍀 Decoupling eliminates ringing of the speaker cabinets AND mechanical feedback to the front end electronics via the floor. See Max Townshend’s video showing ... measurements with and without decoupling. The knee bone’s connected to the leg bone, the leg bone’s connected to the ankle bone, etc.

Instead of arguing about coupling/decoupling, let's talk about the speaker/stand interface, where the bottom of the speaker cabinet comes into some kind of contact with a plate or 3 or 4 leg-tops.

There are multiple options that I've read about.

Cones--of various materials--pointing up, pointing down.

Sorbothene pads, harder transparent plastic buffers, Herbies dots, etc.


Isoacoustics Oreas.

Little bits of exotic woods.

And the list goes on.

Some manufacturers even provided holes to screw the speaker to the stand.  This and Blu-tac may be more for safety reasons than acoustic reasons.  But perhaps not.

And while we're on the subject, consider mass-loading of floor-standers.  For a while there, there were a bunch of models that had a cavity in the bottom for you to fill with your favorite kitty litter or steel shot.  How much different is that than connecting speaker and (filled) stand as tightly as possible?

When developing my speakers and introducing my stands, I had extensive conversations in this topic and did some testing.  I have tried high mass stands, low mass stands, bolting the speakers in place, adhesives, velcro, simply placing the speaker on the stand and IsoAcoustics pucks. 

Easy...the IsoAcoustic pucks decoupling the speaker from the stand was the best sounding.  The pucks go between the speaker and the stand.  I ultimately produced a low mass stand that is machined to ensure proper placement of the puck for my speakers.  

Second best option was having the speakers bolted to a high mass stand.  This does require using OEM stands or modding stands.  
I use Oreas.  This is entirely because they are better looking IMO and sold individually.  Iso-Pucks are basically the same concept, just not as good looking IMO and I believe they are sold in 4s which is less optimal for my design.  

The key with all Iso products is getting the weight right.  There is an optimal weight range for their products and you should pick the appropriate item  based on the weight you are looking for.  

Also, when they issue their weight guidance, it is the total weight of the device divided by the number of pucks.  If a speaker is 26lbs, you could use 3 Indigo or 4 Bronze.  Does that make sense?