Martin, I hesitate to be too definitive because I have found that different things work with different speakers, and can depend on the weight of the speaker. When you screw speakers to a heavy stand you ensure that the speaker's energy has a sink and that the excursion of the speaker will be minimised. The downside is that the stand will store and release the energy over a long period, and will be delivered back to the speaker very easily. If you either rest the speakers on up-turned spikes screwed into the stand, or screw the spikes into the bottom of the speaker, the result will be different. Any significant movement of the speaker will be quickly released to the stand, but will be less likely to be returned to the speaker. I certainly found that this latter method was preferable with several small box speakers (such as Totem and Proac). Principally the sound was "faster" and more open. With screwing the speakers to a heavy stand, there was perhaps an improvement in neutrality, and greater bass weight, but a deadening of the music (which I ascribe to smeering of fine detail). Where screwing the speaker to the stand may be better is when the cabinet has a "lively" resonance and the slowing of the release of this energy is perceived to be an improvement. This is just my theory and I suggest you take it as merely a suggestion for trying something else. If you end up prefering the screws oaver the spikes, then there may be a cabinet resonance issue that might be better dealt with using Vibrapods between the stand and the speakers - I only say might because Vibrapods have their pluses and minuses. But all of this is predicated on you spiking your stand securely to the floor first - which really is a must.