Should I use Speaker Spike / Isolation Base or Something?

Depends. Lots of unknown variables.  You can't go too wrong with spikes through the carpet into the wood floor. Paving slab on the carpet works too, especially with your plastic feet.

I've tried a lot of spikes, Cones, different materials. Best by far are Townshend springs. But if you're on a budget you can DIY springs from eBay, or use Nobsound springs from Amazon. Incredibly cheap, they outperform a lot of much more expensive solutions. Also they are adjustable for weight. So if you decide to upgrade to Townshend like I did its easy to move the springs to use under other stuff like turntable, CDP, amp, etc. See threads around here for more info.

The route is not conclusive as I thought. Kind of tricky situation indeed. 
Thank you for the advice. 

Let’s start with: how heavy are your speakers?

Heavy? Perhaps wheels!  Of course spikes make sense theoretically, but why sacrifice flexibility (alternate toe-in, alternate locations) for theory if you don't benefit from the theory.

I've always had heavy speakers. I've done spikes, feet with textured grips for carpet, thin felt disks to not scratch wood floors, and wheels (3 not 4, more weight per wheel) (rear corner blocks slightly shorter than the rear center wheel, to prevent tipping).

Nothing is lost when going from spikes to wheels if heavy enough. i.e. 80lbs? go to home depot, pick up an 80 lb bag of cement, it can be on wheels and not vibrate. I'm not sure what the minimum weight is when spikes might be advantageous. I would buy some spikes and compare them to the factory solution, simply listen. 

I believe in having ease of movement (mark your best positions somehow), I adjust toe-in when others listen with me to get a wider center, each of us hear both channels well. I push them half way back or fully back depending on size of dinner party, big picnic/crowd, all entension leaves in the dining table ...

btw, it's weight per contact area, with spikes, the contact area is the area of it's protective disc, and that is about as big as a small felt or plastic self adhesive button. something small in the 4 corners, or 3 wheels for very heavy speakers is my recommendation.

Let’s say 67lbs (30kgs). 
One thing I’m not sure is, the speaker has pucks under it. So if I had a hard floor, then I would def just put it. But my rooms is carpeted. 
So, not sure whether I better just put it on the carpet (have the most flexibility), or put a heavy wood piece (3” thick) between carpet and a speaker or spike a speaker. 

Years ago when I had big ATC speakers I always thought the bass could be better so I got a couple of slate slabs to put my speakers on and that certainly helped. I thought it could be better still so I went on E-Bay and bought some car valve springs and put 4 under each speaker and what a difference that made. Try that .a very worthwhile fix for not a lot of money.

millercarbon has the right idea and I can vouch for springs.  I went through gliders, spikes, no spikes, spikes on 1 1/2 inch stone.  I finally settled on Townshend seismic podiums.  They are on carpet on a second story suspended floor and are the clear winner.  To me they are an essential component.  

Agreed. While not cheap, the Townshend podiums under my Focal Maestros did the trick. 

If you can afford to purchase the isoacoustic GAIA  https://isoacoustics.com/products/gaia-series/ for your speaker size and the carpet discs - they are not cheap but WOW they work great !

+1 for Isoacoustics footers + carpet spikes (if needed).  They sit under my ATC 40A towers and work marvelously.  Very real improvement.

Spikes vs springs.  The extremes.  Pucks are intermediate.

I go back to well before spikes first started.  The principle was that if the speaker is prevented from moving/vibrating due to reaction to cone displacement or in-room resonances the sound and particularly the image reaching a stationary listener would not be corrupted by such movement/vibration.

Later it was suggested that the vibration of the speaker under the signal sends mode down the spikes and thence into the floor, causing that to vibrate and create unwanted modes.  Newtonian physics says this must be so.  The modes might be significant with a suspended wooden floor.

That's why, having the opportunity, for the last 30 years I have set my systems up in rooms with a concrete floor screed laid on footings bearing directly on the ground.  Tile the screed if you like but the speakers will bear on a massive solid surface that is in effect almost infinitely mass-loaded as it bears directly on planet Earth.  Any modes reaching the points of the spikes will create less than negligible modes in the floor.  In fact I mass-load support in the same way for all my equipment including amplifiers and particularly turntable where gains in sound stability are remarkable.

MC is entirely incorrect on springs.  This is completely the wrong approach unless they as so stiff as to have no elastic function.  Springs allow the speaker to move relative to a stationary listener and smear whatever signal comes out.  In a worst case scenario it will oscillate like a pendulum under the reactive forces of the spring - it will counter movement in one direction by generating movement in the other - the design purpose of a spring.  The result will be pretty much like saving your money on springs and placing the speaker directly on deep pile carpet.

I am another in favor of the ISO Acoustics. I use the GAIA II and the carpet spikes. Huge improvement on focus and bass articulation.  

I tried all kinds of things....nothing was better than the spikes I have...many a definite reduced performance.  I'm lucking in that my speakers on their spikes, are on ceramic tile, that are cemented to the foundation of the house.

stringreens         +1 +1 +1

stereo5     Why not try with just the spikes?

It all depends on the floor and the speakers. There is a setup man who wrote a great article on why he never uses spikes and why. I had Quad speakers and adding spikes turned them into unlistenable, my current open baffle speakers sound soooo much better with no spikes and just using the feet that the spikes screw into on each speaker. Yes, with spikes it does sound clear and clean, but the body, weight, dynamics are reduced, vocals airy but no chest of weight to it. So much is generalized and becomes something you just do, I have learned over 30 years to think outside the box and try something and see how it works in your system, and #1 your room acoustics impacts more than any power cable, interconnects or a gear change, room focus to me must be #1, spikes, no spikes try it for yourself and listen. My. Dynaudio Confidence 5 speakers sound good with spikes so there you go.

You want to couple the speakers to the floor.
IsoAcoistics will decouple as will any soft things like springs.
For a night and day improvement go with Stillpoints Ultra Minis. They screw into the speaker.
They will couple and turn the vibration to heat. But the movement of the drivers will stay in the box and not be drained into the floor.
You will need 6 x $100. They will be $25 less each since you don’t need the bases. I have them on my 190 lb speakers and the effect is transformative. The best $600 you can spend.

@clearthinker,I used the Triton Refs floor spikes and went with the GAIA II instead as I felt they were a bigger improvement.  The GAIA carpet spikes are cups with metal protruding to grab the rugs, they are not spikes persay.  The footers sit inside the cups which grab the carpet.

Another vote for the IsoAcoustic Gaias. Marten loudspeakers have teamed up with IsoAcoustics for their higher end models.

@stereo5
Your speaker will still be wiggling around and muddying the transmission of your sound.
Blowing in the wind.

@miglik   Your speakers too will be blowing in the wind if you don't couple them to something solid.

The issue is to prevent the speakers oscillating relative to your ears in the listening seat.  That oscillation will oscillate the sound you hear.
Simple physics.

Try not to listen too much to MC.

Noted MC isn't coming in on this.
Boing boing!

Clearthinker is absolutely right. Any vibration of the speaker is distortion. The game is to hold the speaker as rigidly as possible under the circumstances. Springs are beyond belief silly even on a wooden floor which is going to vibrate at it's resonance frequency regardless. A concrete floor is wonderful as least for speakers. Not so much for turntables as there is rumble that will travel through a concrete floor. Speakers should always be spiked if possible. If a stand is used they should be firmly attached to the stand and the stand spiked to the floor. 

clearthinker, you are wrong, wrong, wrong.   Best sound I ever had and I have been doing this over 50 years.   Try some of the GAIA footers and you will eat every one of your words.  Do you like the taste of crow?    And, I will leave it at that.

+1IsoAcoustics Gaia feet

So many posters with the absolute best solution.  If you look, you can find positive reviews for many types of solutions, from both on-line or print publications and from hobbyists on forums such as this.  At the end of the day, you should trust your own ears to achieve the sound you enjoy, which means you should probably try a few different things.
I scanned this thread and did not see whether the floor is carpet over a concrete grade slab or carpet over a suspended wood floor.  Many on this forum have recommended spikes over concrete grade slabs and some sort of decoupling over wood floors. 
If you read the information on the Townshend Audio website, they provide an opinion of why decoupling/springs are a good solution over both types of floor support.  There are several positive reviews (like here and here) of the Townshend Seismic Podium, which is basically a spring-supported platform.  You can try springs without purchasing the expensive Townshend platforms. 
This company provides detailed information such as maximum load capacity, length, and spring rate for a variety of compression springs that you can purchase relatively inexpensively from their website.  You can try simply positioning the springs under your speakers or speaker stands and you can try loosely covering them with heatshrink or placing foam inside of them for damping.  Most try and load the springs to around half of their maximum capacity.  You want enough damping (which the weight of the speaker should provide) so that the natural frequency of the spring/speaker/stand system is below the audible range.  As some have pointed out, Nobsound by Douk Audio offers a product that allows you to adjust the maximum support capacity by adding/removing springs.   
There are other decoupling methods/products ranging from simple hockey pucks (vulcanized rubber) to sorbothane spheres, to products from Herbies Audio Lab products or EVPs by A/V RoomService, Ltd., and more.   
Many recommend spikes such as Sound Anchors, that makes really nice speaker stands.  They send their stands with basic Ramset threaded fasteners, which are used as spikes.  I have used those and have also used really nice large brass spiked feet from edenSound. 
I have ended up with Herbie's Giant Fat Dots in furniture feet protectors on the back side of my speakers and springs in the front....it is a decoupling combination that works for me and my 175-pound speakers on carpet over a concrete grade slab, after trying many.  My two 150-pound subs are completely supported on springs.  When supporting speakers on springs, it is good to recognize that the front side (where the drivers are supported by the baffle) is often heaver than the back end.  You can adjust for this by adding springs where there is more weight.  For example, in addition to springs at the four corners, I have an extra spring directly under the very heavy toroidal transformers in each of my 80-pound monoblock amplifiers, which are then supported over SRA platforms.
Do your own research, try some stuff, and choose what works for you.  Here is an article on vibrations and audio equipment you might look at.  Good luck.

Townsend is the clear winner.

https://youtu.be/BOPXJDdwtk4

Check out Herbies Audio Lab.  I replaced expensive Isoacoustics footers with Herbies giant fat Gliders and could not hear a difference at all.  Much less expensive and the added benefit of being able to glide your speakers over the carpet if you want to slide them out of the way or just adjust the position.

I think that Spikes work well on wood floors
 Other then Spikes soft material  on anything but wood .   

one suggestion, if you can live with it,  is do what i did and cut the carpet completely out from under the speaker.  I then took hard wood boards and ran them across bolting them in to the floor joists for a really strong and solid platform.  Then i set the speakers feet right on those boards. 

I used the brass feet from Mapleshade to great affect,  but now, like a lot of the guys above,  use the GAIA feet under my Thiel 3.7 speakers. 

ClearThinker....The speakers ARE on spikes.....I described the flooring....Travertine tile cemented to the foundation of the house.

I put Herbes under my speakers which absolutely ruined the sound of my Vandersteen 5A's. ....just wondering...if the speakers are designed at having the sound arrive at the appropriate time, springs which allow movement, will blur the sonic picture. no?.  I know that moving my speakers to absolutely vertical because of a  very slightly unequal floor, makes a very real difference for the better.

My experience over the many years in this hobby is that spikes works very good on 
wooden floors.
spikes on concrete floor makes the system 
sounds lean.

@ sangbro
It would be helpful to know what your budget is for speaker feet.

IsoAcoustic Gaia speaker feet has recently garnered many positive reviews, perhaps more than any other feet.   Although not inexpensive, it is my final choice to use on my next speaker purchase (still gathering the funds). 

A simple observation. A member of flour standing speakers come from the fabric on spikes (e.g.  Thiel, done JM Lab). I would not bother myself  further and just trust their experience.