Reference for Rosh Hashanah 54:17
אמר רבה
How much is enough to produce a blast? - R'Simeon B'Gamaliel explained: Enough to allow of it being held in the hand and leaving something showing on either side.' If its sound is thin or thick or dry, it is valid, since all sounds emitted by a shofar can pass muster',<span class="x" onmousemove="('comment',' Lit., 'are valid'.');"><sup>16</sup></span> They sent to inform the father of Samuel: If one pierced it [the horn] and blew with it, he has performed hi religious duty. Is not this obvious? All shofars are pierced!<span class="x" onmousemove="('comment',' I.e., the horn is pierced to make a shofar.');"><sup>17</sup></span> - R'Ashi explained: [It means], if he pierced the inset bone.<span class="x" onmousemove="('comment',' A bone which grows from the animal's head inside the horn, and which is usually removed to make the shofar.');"><sup>18</sup></span> You might think that although it is of the same material it makes a partition; we are therefore told [that this is not so]. IF ONE BLOWS INTO A PIT OR A CISTERN etc. R'Huna said: This rule applies only to those standing on the edge of the pit, but those standing in the pit perform their religious duty thereby. It has been taught to the same effect: 'If one blows into a pit or a cistern, he performs his religious duty'. But have we not learnt, HE DOES NOT PERFORM HIS RELIGIOUS DUTY? You must therefore understand it in the sense of R'Huna's dictum. Some put the two statements in opposition, [thus]: We have learnt, IF ONE BLOWS INTO A PIT OR A CISTERN HE DOES NOT PERFORM HIS RELIGIOUS DUTY. But has it not been taught, 'He does perform his religious duty'? - R'Huna replied: There is no contradiction; the one statement speaks of those standing on the edge of the pit, the other of those standing in the pit. Rabbah<span class="x" onmousemove="('comment',' Var. lec. Raba.');"><sup>19</sup></span> said: