If the purpose of your database is strictly as a buying guide then I don't think that driver size is a very useful metric.Headphone drivers don't need to move very much air so other factors besides sheer displacement predominate in determining bass response.
When golfing.
When, would you say, driver size would be a useful metric?
I'm not really sure what it would be useful for all by itself.All else equal there are many other things it would affect like high frequency response and the frequency of any breakup modes in the driver but by the time you get to a finished product there are too many other variables to make any conclusions based on the driver size alone.
