1) The acoustic are not as good; 2) you’re less like to disturb other people who will mostly hear the shower and 3) you really need to be standing to belt out a solid tune (opera singers never perform lying down).
1) The acoustic are not as good; 2) you’re less like to disturb other people who will mostly hear the shower and 3) you really need to be standing to belt out a solid tune (opera singers never perform lying down).