I have this sub on the carpet spikes that came with it.
Between the carpet and the speaker there is about 1 in., and I've always wondered if by raising the speaker higher (1/2 in.-1in.) I would get a better or a smoother bass response.
Has anyone tried this?

bray, if you do get smoother bass response by raising it, it will have more to do with room boundary interactions than with the fact that the bass waves will have more room to escape from under the sub. In other words, it would have a similar -- and possibly detrimental -- effect as moving it one inch further from a wall.