Discussion at Summer convention: Electrical reproduction from phonograph

C. R. Hanna: In the paper by Mr. Kellogg no mention has been made of factors which determine the sensitivity of the pickup device other than that mass has something to do with it. This statement is made: “The foregoing comparison of magnetic systems does not take into account the possible power output of the winding, nor is the elastic stiffness required to hold the armature in its mean position allowed to weigh in the choice. The comparison is wholly from the standpoint of obtaining the maximum open-circuit voltage with the minimum effective inertia of moving parts.”