Help with JL amp settings

I'm trying to figure out how to set the Input Sensitivity Level on my 250/1. The exact words for what I need are

A Digital AC voltmeter, which I already have.

A CD with a sine-wave test tone recorded at 0 db reference level in the frequency range to be amplified(ex. 50 Hz for a subwoofer amplifier. 1kHz for a midrange application). Do not use attenuated test tones (-10 db, -20 db, etc).


I have no idea what they are talking about with this sine-wave tone stuff. It says to play a track with an appropriate sine wave (within the frequency range to be amplified)

Can anyone explain this to me so that I can see if I can set this right.

A sine wave is just a pure tone at a certain frequency, much like plucking a single string on a guitar or playing a note on a flute or any other musical instrument. ~20-80hz is the range that subwoofers play, midranges play ~80-2500, and tweeters play ~2500-20,000. Since this is a sub amp, you want to use a frequency that the sub will play, so anywhere between 20-80 would work. They recommend 50, which is right in the middle of the range.

Now you just need to find an mp3 or a wav of a 50hz sine wave that you can burn to a cd, so you can use it to set your gain.
http://www.ihearyou.com/testtones/

just one note ..... it is critical that the tone you record is set to 100% digital max volume - meaning at the top of the wave it is recorded as all 1's. If it's not, the levels will be off.