1st...he wanted to know where he could find it...if he finds the site that can and will answer and questions about dyn that he has...
2nd... the figure you quoted....175mmx77mm..... is an overall measurement...including the cone and surround...not mounting depth which (as long as my eyes aren't decieving me) is stated as 67mm from bottom of mounting flange to tip of magnet structure...or you could look at the tech paper....