Speaker diaphragm and speaker using the same

A speaker diaphragm includes a first diaphragm portion , a second diaphragm portion integrally molded with the first diaphragm portion , and a bobbin-receiving portion protruding from a back side of a connecting portion between the first diaphragm portion and the second diaphragm portion , with one end of a voice coil bobbin being bonded to the bobbin-receiving portion . The bobbin-receiving portion includes a first extension extending backwards from the first diaphragm portion and a second extension extending backwards from the second diaphragm portion . A bobbin-receiving groove is defined between the first extension and the second extension . The voice coil bobbin is inserted in and bonded to the bobbin-receiving groove