Does a Subwoofer Make Spiking Redundant?

I just added a REL T5/x to my system, and a question rises up from the depths of my ignorance: Does a subwoofer do the thing spiking speakers is supposed to do? Does a subwoofer make spikes redundant, or do they work at cross-purposes? If it's relevant, I've got the spikes on Herbie's Audio Lab puckies, on a (thinly) carpeted floor.
"Does a subwoofer do the thing spiking speakers is supposed to do?"
Are you asking if it is worthwhile to spike subwoofers? If so, according to many who use them, it is a good thing. I think you're just asking the question wrong. Spiking and subwoofers are obviously two different things. 
Not the subwoofer, the main speakers. Or rather, the main speakers were spiked before I got the subwoofer. If it's true that they're two different things then that's the answer to the question. 
Never use spikes. Use springs like Nobsound, or even better Townshend Pods or Bars. Or the very best, Podiums. I’ve compared and Townshend are by far the best. Spikes, the worst.
Then mids will still cause vibration. The type of food the speakers are on matter too. Carpet over concrete or wood etc. 
What you are trying to do is fix a small mass to a much larger one to drain away excess vibrational energy, to dampen resonance. It is the exact same principle you use when you fix a cartridge to a tonearm. Ideally you would bolt the speakers to the floor and I have seen people do this. The problem is the mass of your house is not solid. It vibrates also. Here a concrete floor is also a big plus but an option many of us do not have. After bolts spikes are the next best thing. Both subwoofers and main speakers should be fixed although it is more important for subwoofers. Putting speakers on isolation springs is an odd thing to do for two reasons. This allows the speaker to vibrate itself silly and the floor is going to vibrate just the same from the acoustic energy released by the speakers. So, if you want the ultimate, bolt your speakers to a concrete floor.
Unless your floor is concrete, I would think isolating your subwoofer would be better. With standard wood frame construction, you don’t want the sub to couple to the floor which then acts like a radiator vibrating at its resonance frequency, mucking up sound quality. When I isolated my subwoofer from the floor, sound quality went way up. I noticed that it didn’t interact with the room as much - much less vibration coming thru the floor. If your goal was maximum loudness and impact, maybe you want that effect, but you don’t where sound quality is the objective.
Always decouple, everything. You cannot be heavy enough or secure enough. The problem is timing. The floor, weather wood concrete or whatever folks use can’t isolate vibration unless it’s thick rubber, THICK rubber like the Kursk 3" thick.... Most people don’t have that type of isolation. 10-12" thick concrete will work. 3.5 or 5.5" is not thick enough unless it’s on friction piers. That is an expensive slab...

It’s better to use air bags, spring or pods. The better isolation you can afford the less the timing issues. Smearing is a PITA until you get rid of it.. Like magic!

Clean up the huge passive bass radiator from the floor walls and ceiling. Treat the standing wave issues in the room, you’re sittin’ in TALL cotton (as my Mom use to say) I use heavy curtains and two pocket doors that slide open on the back wall in one room. My ears don’t like to much pressure. OB servo subs really help. I use to use inner tubes on 2 12cf bass bins and set the feet in a pocket of 4" memory foam, 95% isolation.

On spikes they would have drilled holes in that 41/4" 80 year old concrete floor, close to 300 lb each.

I have a pair right now 250lb (12cf) with no driver holes yet. A pair of 21" Daytons, would act like pile drivers on spikes. Turn up the bass and it would leave concrete dust on the floor.. LOL

" bolt your speakers to a concrete floor" - this is completely wrong.

The whole purpose in "decoupling" the speakers, and sub, from the floor is to minimize, or eliminate, the vibration from reflecting back into the speaker. This reflecting vibration muddies up the sound of your speakers. Eliminating the reflecting vibrations tightens up your bass, and the speakers’ sound becomes more clearer. Bolting the speakers to the floor will only insure that the vibration passes from the speaker into the floor, and reflecting back into the speaker cabinets.
Spiking the speakers will only minimize this vibration. The best ways are to use springs, as suggested, seismic podiums, or energy dissipating pucks.
My system is on the second floor. I added some of the mentioned Nobsound springs to subwoofers and noticed my kitchen lights (one floor bellow) don't rattle as much. However, I feel as though my subs lost some punch.  
i read a lot of this and find it confusing. certainly contradictory ( what else is new?).
There are many theories, but the most reasonable, to me is that we want speakers to be totally immovable - a solid, stable surface for drivers to push against.  If they resonate, they modulate the drivers - especially the midrange and tweeter where the wavelength is smaller relative to any vibration or rocking motion.

Spikes are often used to cut through a soft, unsupportive material that will allow the speaker to rock, such as a carpet.  The subwoofer OTOH adds lower frequencies and is mostly an orthogonal choice.

Now, a spike on a hard surface is a different animal and I would tend to not use them. Those spikes minimize the surface area (which in the newtonian sense of friction m,akes no difference), but also increase the force per unit area meaning the connection will be more fluid due to material shear. In theory. This is why car tires are non newtonian as well (wider is in fact better).

I prefer mass to stabilize the speaker (big, heavy speakers on a solid 3-points so they don't rock) and maybe as one suggested actually isolating the speaker from floor vibrations especially if its a live floor. I have not experimented with those.

Acoustic Science Corp and Acoustic  Fields have Subwoofer Platform Traps 18” off the floor for more than one reason. 
My speakers are spiked, heavy carpet, pad and plywood underneath. 
   If I place on rug, they are tipsy. 

What else you recommend?

I looked at those Townshend Podiums. You must understand that those things go for about what I could afford to pay for a speaker. Of course, if you're playing a $299 copy of In-A-Gadda-Da-Vida through an $8,000 speaker, it's perfectly proportional.
Hello Miller, boing boing, you are still wrong.

Heretobuy.  Your are saved from suffering bad SQ from Miller's heresy not by your own wisdom but by shortage of funds.  Whatever!  More than one way to save yourself!

Most of you have misunderstood OP's question.  He asks: if you have subwoofer(s) does this mean you don't have to spike your main speakers because you don't need them to produce articulate low bass.

OP misunderstands the reason for spiking.  It is to prevent the whole speaker moving around and adding that movement to the signal driven movement of the cones etc.  We need to listen to the signal and not the extraneous movement that smears the sound and the soundstage, across the whole frequency range, not just the bass.  Remember, even if you add subwoofer(s) your main speakers are still reproducing low frequencies as before, unless you mess with their electronics.

PMM.  If you bolt (or spike) your speakers to a concrete floor laid on the ground with a good rigid foundation, the vibration passed into the speakers is the vibration of the mass of planet Earth.  That's quite a lot of mass to move around!  There again, Red Indians used to put their ear to the ground and heard riders and horses miles away.  At least they did in movies.
lt would be fun to do a blind test with and without spikes.  Then demo the subwoofers without spikes and tell the listener they are listening to subwoofers with spikes how many would either hear the difference or because they were told they were listening to a subwoofer with spikes automatically convince themselves because they were told they were listening to subs with spikes they sounded better.  I call this the EMERORS NEW CLOTHS SYNDROME.
My speakers are spiked, heavy carpet, pad and plywood underneath.
   If I place on rug, they are tipsy.

The job of the spikes is to pierce the carpet. Lose the plywood and pad.  But you may leave a mark on the underlay if it is hardwood.

OP misunderstands the reason for spiking. It is to prevent the whole speaker moving around and adding that movement to the signal driven movement of the cones etc.

right. A different way of phrasing what i wrote above.  It is modulation.

When I put spikes under my speakers I could definitely hear a marked difference. If a blindfolded person could not hear the difference then I think it would be more a matter of The Emperor's Cloth Ears. The thing was, I wasn't really sure at the time that the difference was an improvement. Getting the spikes in the puckies I was putting the tips of the spikes into was such a nuisance, me working alone and all, I didn't want to go through the trouble of removing the spikes only to find I liked it better spiked and have to do it again. I might give it a try, but I wouldn't want to do it before the subwoofer burned in. I'm not the sort of person who runs his gear hour after hour to get it burned in - I live in an apartment. (In fact, when I watched a move - Many Saints of Newark, as it happened - the movie soundtrack bass was so thumpy that I might have to turn the subwoofer off when watching moves.) So I will let the subwoofer to burn in the course of nature. I did the same thing with my front speakers - at first I was a bit underwhelmed, but a month or so afterward I started to become aware of how much better they sounded.

Clearthinker— Mc is always wrong. Instead of asking questions about the floor, the speaker, or is a sub, he just blurts out garbage.

It all depends on the flooring and what does the speaker manufacturer recommends. For Tekton speakers, springs or spikes won’t make any difference, but ask Magico what they recommend and you will get the m-pod choice which works great for their speakers. Same goes for Wilson and others. Me, I would look at Isoacoustic pods for the speakers if on a plywood/joist floor or spikes on a carpet/concrete floor