I don't trust any model below Fs for a driver unless it is very low Q.\n\nNo matter what the model says you should not drive a speaker below fs unless it is very low Q, around 0.25. That includes woofers mids and tweeters.\n\nIt is clear from the TS parameters the driver in question is designed to be used in a small sealed box. This way the air pressure will restore the cone to neutral position and keep cone excursion within bounds at full power.\n\nMy model does not show that you can use 600 watts in a larger box. In fact it shows over excursion with the 3 db reduction I built in. In addition as with all extended bass alignments the response is not as smooth.\n\nAlso for a high Q driver I would not trust any model below Fs.\n\nGenerally optimal alignments give you an F3 a little above Fs. My model pushes it as far as I dare, with f3 just a little above fs of the driver.\n\nAs in all speaker projects the first and a crucial step is correct driver selection for the project.\n\nI can understand a new builder not realizing that speaker drivers have defined applications, and when trying to specify a driver outside its intended application things can get at least difficult and often impossible.