Measuring speakers

You would need some sophisticated equipment and a suitible environment to replicate testing as done in the mag's.

As a pratical matter even if you could it wouldn't make much difference in actual use since the room and speaker placement makes a huge difference.

Buy a test disc and a Radio Shack sound level meter and use it to set up the sub's and integrate their response with the main speakers. Easier than doing it by ear.

Newbee is right, but the closest that you can come is to measure the speaker in a quiet, outdoor environment lifted well off of the ground. Use a CD with test tones, such as those inexpensively available from Stereophile or a tone generator and a sound level meter, the Radio Shack model mentioned is very inexpensive and should work nicely.

Buy a test disc...

Or make one on your computer (if you have one). Freeware is available for both Mac and PC. Save your file to AIFF (Mac) or WAV (PC). Then burn your file to a CDR. You can make a disc not only for your sub to main crossover, but for testing your whole system as well. (or if you do not want to go through the motions, just buy one!)

I prefer to make my own because I can pinpoint any frequency I choose.

there is also SW that dive you greater control than CD test discs (this may be what Jamscience is refering to to make discs). I have 2 packages, one freeware called "Multigen" is a frequency generator that generates simply sine waves - it has continuously variable frequency. It also allows more complex harmonics contruction. The other is AQT (Audio Quick Test) - it's more sophisticated and costs $. The entry version is $30. I'm only a user of these, not afilaited with either company. I have them loaded on a laptop that I connect to a pre-in for testing in room setup. I us the RS meter for amplitude measurements, but as has been said, this is highly imprecise. Finally, Jamscience's suggestion to burn a cd is a great idea for more quick testing. It's much easier to load up a cd, than to connect up a laptop, boot up, etc, if all you want to do is run a quick scan.