Hey! For me, this produces sound for the whole range of heights/frequencies! It plays a bit more silent for high frequencies, but for the lowest ones, the sound is quite loud (given it's produced by a screen...) and I think, it could easily go for an even lower pitch.
I am using a modified SyncMaster 203B (I replaced some of the electrolytic capacitors after the lighting ceased to work, so that may be it...)