If the EV 257 is not included, I wonder if you can input a response curve on your own? EV ships many of their mics with individual response curves (a nice by-product of good QC). The more I think of it, entering one in manually might be more trouble than just borrowing another model from someone. I'll check tonight after I mow the lawn...

Yes, you can enter your own response curves in SpectraLAB. They give detailed instructions. I found it easier to just use an existing template instead of second-guessing myself wondering if I'd gotten it right.

And for more details about the procedure, make sure to read my original thread on the topic.

Someone else also posted about the Praxis RTA software, which doesn't have a 30-day limit. Not that I've used either one; just another option.