Under my tower speakers -- Isoacoustics Gaia, other options?

Thank you, thought floor was bare concrete. Which,would benefit from a block or a thick rubber pad.

the racketballs sure helped,dampen,vibrations in my rack

Hey hilde45...

In my long experience as an Anti-Resonance Cop (especially under the hood) masonry rarely works.  If your floor carpet is thin enough, you might try to find some vintage golf cleat spikes and weigh down the speakers:

50_31067b_lg.jpeg (1200×1600) (iconicauctions.com)

I've also been pleasantly surprised with bookshelf monitors atop carefully weight measured Vibrapods, isolating in a somewhat 360 degree fashion, despite most preferring mass loading with loudspeakers.  Aluminum isolation cones can work well and are reasonably priced.  As stated, adding some mass to the top of your loudspeakers can prove effective depending upon the approach used.  Sound dampening the boxes internally and/or externally can prove extremely rewarding.  

More Peace, Pin           (bold print for aging eyes)

isolation recommendations without specifying floor type are meaningless.  

@OP, you've been around long enough to know that everything matters. This includes vibration. The link below should be required reading for anyone after good sound. This article is informative and debunks all the hooha about spikes.

A novice reading this thread would be forgiven if he was to heed the advice so far which is to use spikes. The majority say spikes which is not true. If you merely seek stability then spikes will help but the aim here is to get better sound.

The author uses a tuning fork to illustrate his theory and reasoning.  I made up an old tonearm and cheap cartridge to measure the amount things vibrate and by using a signal genny could see first hand and at what frequency the vibrations were occurring. Simply rest the stylus on the concrete floor, wood floor, furniture, audio rack etc. and measure the output with your multimeter at intervals. Doing this is far far better and more enlightening than random noise on a forum. Most of the posts here are recommending spikes but unfortunately they are wrong.

I met Max Townshend at the XFI Premium show in Veldhoven, Holland in 2019 and we had a long chat where somehow conversation also turned to his supertweeters which is another area for gaining more from your system. Regarding the topic of interest here, he had 2 identical pairs of speakers matched for height and using same source, amp, cables and of course acoustics. Switching between the pair with factory feet and the pair on his platform was not at all subtle. Pricey, yes, but way better value than the Gaia footers I installed on my OB speakers. I heard very little from the Gaias on Isoacoustics carpet spikes on medium pile carpet on concrete.

Don't concern yourself about rigidly coupling to the floor. Intuitively it would seem that the more solid the mount the better but some guys are suspending their speakers from the ceiling on fishing lie or similar and reporting improvements.

Ok lets assume a speaker weighs 40Kg and the woofer cone weighs 40 grams. What's the ratio in mass? it's 1000:1 which translates to 0.01dB  Do you think you will hear that???

This was not intended to come off as a lecture 🙂  Please read the link.

Since vibration control is not really an issue with concrete floors, you may want to try a speaker platform like the Symposium Segues I use under my tower speakers to clean them up from internal vibrations inside the cabinet. They can be custom sized to extend beyond the speakers by a few inches on each side to give a little more stability if they came with some kind of outriggers.

Although mine sit on a wood floor which on top of a suspended floor over a crawl space, the owner of Symposium Acoustics said locating them a few inches might be a negative and the platforms provide some isolation as well.