Alternative to Speaker spikes

I don't think the furniture leveling feet will do the same job. Spikes are meant to couple the speaker to the floor. A disc-shaped footer will float on the carpeting, and not achieve the coupling. This may or may not be a bad thing. There are differences in opinions about the affects of coupling. You'll have to decide for yourself which sounds better. If the spikes are thin, they shouldn't do any damage to the carpeting. They may leave a small hole, but this is easily brushed over.

If there is no danger of the speakers being bumped into then consider floating the speakers on Aurios MIB. Even the original model, now termed 1.0, can create an enhanced speaker performance. If you place one or two granite or marble tiles from Home Depot on your rug to create a level surface beneath each speaker then place one set of three Aurios MIB for $100 used per speaker between the tile and the speaker. This only works if speaker cable is supported so that there is no pulling on the speakers. You can "tune" this tweak by placing a non-rolling isolation block under each Aurios. These blocks are $10 per set of four from Audiogon member Rcreations ( I think this is correct spelling) and consist of ribbed rubber surrounding cork center. There are many discussion threads about coupling versus de-coupling. The Aurios MIB's help many speakers sound better, even if it is so different from the popular spike method.

Buggtussel loudspeakers makes rounded brss feet for their speakers. They do not puncture the carpeting, and do a good job of connecting the speakers to the floor. I think they will sell them separate.

Dave