Forget tiles or glass, etc. They are flimsy and breakable, with a relatively high resonant frequency. Get some corian (the stuff they make kitchen counters with). It's a resin product, very heavy and non-resonant. You can find it cheap at flea markets or through a plumber or contractor who cuts holes in it to fit kitchen sinks, etc.
You can have it cut to size, to fit the footprint of your speakers. Drill holes in the corian slabs and install spikes into them. Then put your spiked speakers on to the corian.
Great isolation, better sound.
You can have it cut to size, to fit the footprint of your speakers. Drill holes in the corian slabs and install spikes into them. Then put your spiked speakers on to the corian.
Great isolation, better sound.