Hilchot Shofar 1:7-8 (Blowing a shofar and the sound is thick, thin, or dry – is that OK?)
12:46 pm
Can a person cut a shofar to make it shorter? Can he scrape the inside to make its walls thinner? If the sound of the shofar is thick, thin, or dry, has the listener fulfilled his obligation? What if he hears the echo of a shofar rather than the shofar sound itself?