<font color='#000000'>Interested to hear how you folks do it. I used to think that getting something with test tones and an SPL meter were good enough but I have come to realize that it is not necessarily so. This simple method relies on one very big assumption and that is that the speakers you are calibrating have fairly flat frequency response curves. I have seen bookshelf speakers that come close to being flat but I have yet to see a sub with a flat frequency response. I'm currently in the process of measuring my speakers frequency responses over 30-62 hz and 200-1250 hz, constructing best fit lines and matching those in hopes of getting a better blend between my sub and my bookshelf speakers.</font>