3 Attachment(s)
AlNiCo 077/2405 Blue Golden Silver Diaphragm
I have done some measurements all with AlNiCo 'motors' and 077/2405 horn ("slot")
First figure 077 with "Blue-Blue" rings diaphragm
Second figure 077 with "Golden-Golden" rings diaphragms (D16R2405)
Third figure with 2405 (AlNiCo) with "Silver-Silver" rings diaphragm (marked as 2405 from year '84)
It seems to me that nowadays D16R2405 dia is somewhere "in between" older sisters 'blue-blue' and 'silver-silver'(from early 2405-AlNiCo) diaphragms.