Yea, spiking a speaker couples it to the floor pretty effectively. Whether it's a good idea depends on what you're coupling it to, though. If you're spiking it to something solid, then it will help to stabilize the whole enclosure and can improve the sound by, in my layman's understanding, effectively adding to the inert mass of the enclosure. If, however, you couple to enclosure to a less inert surface (such as a suspended, wooden floor), you are really only expanding the resonating surfaces that can muddy or otherwise affect the sound. Spiking a speaker to a less-than-solid and inert surface is always a crap shoot. Pretty simple to diagnose, though -- if it doesn't sound right, it's probably not a great idea.
There seem to be two basic approaches when straight spiking doesn't work out. You could either seek to decouple the speaker from the uncooperative floor (air bladders, vibra pods, various flavors of isolation shelving, and countless other products or homebrews) or put something solid and massive under the speaker and couple it to that (ye old slab of granite, e.g.). Then, of course, you could always mix and match the two, such as when you hear about folks putting a slab of concrete on a bicycle innertube and then putting the speaker on that. Folks'll argue over what works best but, depending on their gear and circumstances, they're probably all right. I sincerely doubt there's any single cure-all, but I'm sure, in any case, that spikes aint it. Assuming you think it's fun to try new stuff, then anything that sounds like it's worth a go probably is. Have fun and best of luck.
There seem to be two basic approaches when straight spiking doesn't work out. You could either seek to decouple the speaker from the uncooperative floor (air bladders, vibra pods, various flavors of isolation shelving, and countless other products or homebrews) or put something solid and massive under the speaker and couple it to that (ye old slab of granite, e.g.). Then, of course, you could always mix and match the two, such as when you hear about folks putting a slab of concrete on a bicycle innertube and then putting the speaker on that. Folks'll argue over what works best but, depending on their gear and circumstances, they're probably all right. I sincerely doubt there's any single cure-all, but I'm sure, in any case, that spikes aint it. Assuming you think it's fun to try new stuff, then anything that sounds like it's worth a go probably is. Have fun and best of luck.