Spikes or rubber feet.

I prefer the rubber feet. They decouple the speakers from the floor. Also, they are far less hassle.

If you hear tremendous differences between USB cables (for example), you have golden ears and should try the spikes. Otherwise, just enjoy your speakers (and unmarred floors) the way they are.

Find out what gauge thread the inserts in your speakers use, and then buy some Herbie's threaded gliders.

@gphill 

I called Aerial and talked to Michael Kelly about this very issue. He recommended that I use the spikes since my floor was not a slab but a floor with joists over a basement.

Interesting since it is usually the other way around.  Decoupling typically sounds better over a suspended floor (i.e., over wood joists).     As some have mentioned, Herbies makes some decoupling products.  If I still had my system set up on the upper level of our house, I would consider trying these, which came up recently in another thread.
http://avroomservice.com/evp-2/

I have owned two different types of Aerial speakers and in both cases used Sound Anchor stands to increase the weight and improve stability (i.e, the stands extend out wider than the speaker base).  You could used either spikes or decoupling materials below the SA stands.

Fat parrot made me smile for the first time in a week.

Like others have said, just swap them out and determine which one sounds better.

btw,

I put tower speakers that could easily tip over if only 3 spikes (or my current 3 wheels). Trick is, put blocks in both rear corners, just a bit of clearance so the rear spike/wheel only is supporting the speaker.

Then, for any reason (fat parrot gets out of the cage, perches on a rear corner) if it starts to tip, the wood block prevents it from going over.

Rear spike height fixed, adjust two front spikes for level/straight appearance

Nice line of speakers, and the OEM evaluated them with both the hard rubber or spikes, provided both in case you wanted to try spikes.

My speakers are very heavy, close to 200 lbs I bet. I’ve done hard but ’slidable’ bottom pads, felt, adjustable spikes with the dimple disk on wood floor, and now 3 wheels.

Theory is one thing, perceivable results another, no one could hear a preference, so I go for 3 wheels to provide mobility (more weight per wheel than 4, and 3 never wobble) (some minor compression tracks in the wood floor) Back in corners when expanding the dining table for family holidays. Or out of the way for access to components. Hard to get em moving, but move they do. Grid wood floor, easy repositioning.

I think pick your evaluation music, a good listen as is, then try spikes, IOW, like me, and my friends, you need to know the answer. My guess, no difference, back to easier hard rubber. I sometimes alter the amount of toe-in, my friend with spikes, it’s a monumental effort to try a different angle.

Your speakers, being towers, you need 4 pads, spikes, wheels, so it is imperative the spikes are adjustable or you have sturdy shims, lack of proper weight transfer on 4 spikes can defeat the idea of super stability.

I use these under my spiked speaker stands & audio rack on hardwood floors, they work great.

https://herbiesaudiolab.com/collections/loudspeaker-rack-decoupling-and-isolation/products/cone-spike-decoupling-glider

Alternatively, if you are on the ground floor cut a speaker sized hole in the floor, pour concrete into the bare dirt(might be best to excavate a bit and frame it)and viola a perfect pad for your speaker to sit on. Wooden floors nearly always move.

I tried out the differences between spikes and hard rubber pads, also due to oak hardwood parkett flooring in the past. 

The difference with my Burmester 961 speakers (35kg each) was so great that I *had to* go with spikes and that fiddly setup with those dimpled protector disks.

The spikes in these situations are seriously inconvenient but due to the very clear sound improvement a must, as far as my experience goes.

I now could organise two round, polished and baffled granite disks (reshaped from kitchen top cutout left overs) and place the spiked speakers on top of these.

This works really well avoiding floor damage even on tiled flooring.
M. 🇿🇦 

If the rubber flexes at audio frequencies,  the cabinet will also vibrate enough to smear the image. 

I have Aerial 7t’s. When I first got my speakers home I called Aerial and talked to Michael Kelly about this very issue. He recommended that I use the spikes since my floor was not a slab but a floor with joists over a basement. Once I found a good spot for the speakers I put the spikes on and never looked back although they are on carpet.

Agree, these are Aerial Acoustics. This is my second pair. The cabinets are rock solid. The rubber feet are from Aerial Acoustics. But, they are fairly hard.

@n80,

Rubber decouples, spikes couple.

Accelerometer readings indicate that there is far less vibration/resonance through the baffle if the speaker is decoupled.

It’s also possible that a loudspeaker may sound 'better balanced' despite greater baffle resonances but for greater resolution I’d prefer to use rubber feet to decouple.

I don’t think it’s anything to get too concerned about when it comes to well designed loudspeakers. Any decent designer would no doubt have worked very hard to reduce cabinet resonances to a minimum beforehand.

I have a rug floor on my floor the polk lsim707 came with rubber and metal spikes.i use the rubber. NO problem. 

If you the spikes, put felt pads w/adhesive backing on the discs. You can then slide them on the hardwood for easy positioning.

Go with the spikes and metal disks (floor protectors).

Thanks guys. I'm not looking for a solution to a problem. Just wondering what the best of the two options would be.

The hard rubber feet came as original equipment on these speakers and they are fairly high end.

The metal discs with the dimple for the spike will do the trick. The "rubber" footer is questionable. You might want to also take a look at Herbie's gliders or wait until others who've used them chime in. 

You're going to get a lot of recommendations so be prepared. 👍

All the best,
Nonoise

There us supposed to be a SQ improvement.
You will never know until try.