[Antonmb]

I’ve always operated under the assumption that it depends on the type of floor. If you have a solid floor like a concrete slab, whether carpets or with wood overlay, anchoring the speaker with spikes has the benefit of stabilizing the speaker so that it doesn’t move around, causing blurring of the image. If, on the other hand, you have a suspended, springy floor, spiking the speaker will excite the floor and won’t keep the speaker from moving anyway. So, spike for a solid floor and isolate for a sprung floor.