Shady has given you good advice. However tones are second best because of continuous duration. Pulses are better. You really do need some sort of measurement for calibration.
However music can be useful, especially if you have a set of speakers that will play into the 40 Hz range.
If you are using music, use music without a lot of, or any for that matter very low frequency content.
I like to use baroque music well recorded that has a continuo bass line. If the sub is properly adjusted then whether you play the music full range or with the sub it should sound the same.
If the bass is louder and the bass strings are starting to sound the least elephantine, then the sub is TOO LOUD.
Generally subs are turned up way too loud the way most often used and are a menace to realistic reproduction. Ideally a sub should be seamless and not heard.
The trouble is people fall victim to the "I paid good money for this sub and I jolly well want to hear it". When they jolly well should not be hearing it.
The real problem is that getting deep bass is the easiest part. Getting good quality bass is the hard part.