I think they might actually be doing the opposite of what you suggest - they generate overtones that cancel out the overtones produced by the speaker itself.
I have been listening on studio monitors for years, as I prefer the sound over the typical consumer audio sound.
Sure, they won't shatter your room, and they are really only powerful enough for listening from close distance, but the thing is how the bass sounds like real bass, rather than loudspeaker bass, it sort of adds weight to other sounds, rather than being directly heard and the whole sound often almost sounds like if it wasn't coming out of speakers.