sound waves propagate in many directions through the bridge when a string is vibrating thus the heavy lines with arrows in fig4 denote that particular path of wave travel that occurs from the point of wire contact with the groove to in the precise direction of normal string movements it should be understood of course that all angles of reflections here are equal but opposite to the angles of wave incidences and that the change in medium from wood to air at the slits 39 edge and groove creates the reflections since the slits are located so closely to the grooves lateral emanating sound waves are quickly directed downwardly to the bridge base and to the diaphragm with minimal attenuation the result is added volume clarity and a ringing tonal quality with reference next to fig2 and 5 a four string banjo bridge 40 is shown which has a crown 41 and a base 42 that has two base feet 43 the crown has a top edge 44 which is formed with four wire string holding grooves 45 a plurality of slits is again formed in the crown such that a pair of slits 47 and 48 straddles each groove each of the slits 48 here is essentially the same as the slits 30 in the previously described embodiment and serves the same function each of the slits 47 however is seen to extend obliquely from the crown edge 44 at an angle to redirect sound waves travelling generally laterally from a wire w held within a groove 45 downwardly towards the base portion of the bridge this serves to amplify the sound in the sense that the sound ultimately generated by the banjo is louder than that generated with bridges made.