inexpensive way to measure speaker performance


So I recently picked up an Auralic Altair G1, and I am very happy with the unit so far.
It does have a parametric EQ feature built into it, and I would like to take advantage of that for my 2 channel listening (my system also is set up as my home theatre, but I use the Krell Foundation 4K speakers level settings to make that work for home theatre)
What is a good (and inexpensive) way to get measurements of what my 2 channel system is putting out so I could use the Auralic's internal EQ to try to manually smooth out some rough spots?
I assume whatever it will be would involve some kind of software and a microphone?
Sorry, I have never done this outside of built-in room correction features on various receivers/pre-pros so I am not really sure where to start looking.
Thanks!
babyseaotter99