Bit of a convoluted tale follows -
I was firmly 'taught' all about using spikes on a visit to Linn some decades back. Ivor himself and his then 'number 2' did the dem using Isobariks with their stands (as I then owned) sitting on a carpet and then putting hard rubber feet under the stands to cut the rocking down (this was before spikes came along so you can see how terrifyingly far back it was). We did the comparison (no volume was changed) several times and in each case, the bass improved in clarity and later on, I found with these and other speakers that if you got the bass right, the rest improved as well. At lome and with said 'Briks close to the wall behind, I jammed a cassette box between the top edge of the speakers and the wall thus making the carcasses rigid every way except downwards. The highs definitely improved/got 'snappier' (again, taking said cases away and then putting them back) but the bass didn't appear to change. Back then, it was suggested to screw some cross-head screws through the floorboards and place the spikes located into the screw heads. That sorted it, but any extra floorboard vibration didn't seem to matter so much.. Got to say forty or more years on what the people buying the house might have thought, seeing holes in the floorboards in what was 'my' room covered in carpet, the 'pile' of which closed up once said screws were removed ages later...
So to this day, I can't understand the newish fad for decoupling the speakers from the floor and allowing the boxes to wobble around. Sorry, but that's my experience and conditioning!!! 'It's different therefore it's better!' is the cry I so often read! One chap living in a flat in a converted Victorian house with wooden floors and a sound-sensitive neighbour below did use a set of Gaia-style decouplers under his stands and rated them highly at minimising bass transmission to the flat downstairs, so i have to give credit where due as for him, the compromise of using them suits both him and the neighbour-relations
Now, I have to say that the original Isobarik stands weren't too rigid themselves. Certainly they were solid in a vertical plane and front to back was OK as well, but you could make the cabinets 'boing' sideways if you tapped them firmly on a top side edge while resting fingers on the other side. As all the 'energy' of these things was front to back and up and down, it obviously didn't matter so much initially, although much improved box-frame stands came along some years later with mdf based fillers for thre eof the voids in each stand to make them solid in all planes and the recommendation was to put an old jumper in each of the cavities to break up any refpections or whatever going on. By this time I was moving on, but the NS1000M's I replaced them with were also placed on spiced (at the bottom) stands. The idea was a simple one. The cones-n-domes of the speaker ONLY should move, but NOT the boxes and
especially the front baffle! I remember when KEF started decoupling the bass drivers from their front baffles and although there were undoubted measured improvements steady state, music with forceful percussion sounded horrible on each model thus equipped with a 'phat' bloated kind of quality not really borne out in steady state response plots of the period I remember. (another music destroyer was the 'positec' protection that some speaker crossovers began to be fitted with at this time, soon abandoned)
What to put between stand and speaker bottom? I saw the severe damage done to the underside of speakers sat on top spikes and the Isobariks when placed on modified stands with nicely radiused top 'points' would actually sink up to the 'shoulder' of said points given time - UGH!!! We found some clear self adhesive 'bump-on' style feet 12mm x 3.7mm approx. from RS components (similar types can be got all over) and these stopped smaller speakers sliding off the stands and didn't squash when larger boxes were placed on their stands. being clear, they don't stain wood speaker boxes nor wooden floors if used between stand and floor but care needs to be taken with heavier speakers that said feet don't 'creep' as some do.
Lastly, one of our accessory suppliers used to sell us 'spike shoes,' two inch diameter or so nicely finished metallic discs with an indent in the top for spikes to locate in and rubbery pads to sit on the floor. Perfect for concrete but the blacking in the rubbery bottoms could stain nicely finished wooden flooring. greyish coloured rubbery pads followed and this sorted it. I think Linn did some, added their markup to it and called them Skeets from memory.
So, what does this tired old eejit use now under his 'BeeBeeCee inspired' thin wall boxes? I use aforementioned clear feet stuck on a couple of custom sized oak lamp tables to sit the carcasses on and said four poster table-legs sit straight on carpet!!! 'Sounds' ok to me but these types of ported thin wall speakers don't seem sensitive to being 'held' still while only the drive units move as the baffles may well 'flex' albeit very very slightly, the ports usually fitted adding to an organic 'bloooom' that some of these models can exhibit low down. Herself is expressing dislike of the tables now, so maybe I'll go all sheep-like and try some UK made 'HiFi racks' black wooden stands, but these are expensive (even at trade prices) and look a bit 'posh' for the sake of it. I'll have to check 'em out in more depth, but they at least will have spikes on the bottom to properly couple to our concrete floor
Here endeth the mini-essay above...