International health groups say earlier treatment can lengthen the lives of HIV sufferers.

VOA: standard.2009.12.02

That's the harmonic series that's on that, and what the valves do is they shorten and lengthen that vibrating column of air very much like the cello string on the fingerboard.

这就是圆号上的泛音列,活瓣的作用是增长或减短,空气柱的高度,很像大提琴指板上的弦

耶鲁公开课 - 聆听音乐课程节选