[Creative cut designs]

How important is it for either spikes or rubber feet on a subwoofer?

[Hobbsmeerkat]

It depends on the type of floor of the room it will be used in.
Spikes for solid, concrete,  ground-level floors, and dampening rubber for wood-frame and suspended floors.
But you can use either option group level concrete tbh. Although, if a sub constantly causes things to rattle in your room/house, dampening will likely be your best bet.

[Creative cut designs]

Thanks much !

[Rock Ball]

I'm experimenting with tennis balls.  My listening room is above a two-car garage so the floor is wood.

First, I had the subs sitting on the carpet.  Next, I tried them with spikes on.  Finally, I tried the tennis balls.  There are 15 under each sub.



Because all three drivers face forward, the weight of the magnets make the center of gravity more towards the back.  I placed the middle row of 5 balls closer to the back. 



I was surprised at how little the subs wobble when you push on them.  They do not move around easily at all. My wife says that the bass is not as loud in the rest of the house now.

I am happy with the performance that I get from these, so now I will make a black cloth skirt to hide the bright yellow balls even though my wife likes the look of them the way they are.

[Hobbsmeerkat]

That's actually a really cleaver idea!

[Rock Ball]

I got the tennis ball idea from YouTubers who were using them to build drum kit isolation platforms.

Another option might be black handballs or racquetballs.  I don't know if they are sturdier or not, but I would prefer the black over bright yellow.

[Creative cut designs]

That's interesting

[rajacat]

These work well and are reasonably priced.
https://www.svsound.com/products/soundpath-subwoofer-isolation-system

[Danny Richie]

Does your brother know that you got into his tennis balls?

Rule of thumb on this stuff is that if the floor is lossy (suspended floor) then use a damper.

If the floor is a solid slab of concrete then spike it to the floor.

[GeAllan70]

then PENN are ok... i go for the Wilson US Open Extra Duty myself... 

[Rock Ball]

Does your brother know that you got into his tennis balls?

This was after the lockdown started, so couldn't go steal some from him.  I still haven't heard his NX-Oticas.