yes, it is unusual.

Most people want to plug into their mp3 player and send signal to their home stereo or car audio.

And going back to my first post... you need more sub.
At volume 5 (of 25) you can start feeling the sub.
By 10, it's right there.
At 25, your chest feels funny after a while.

Keep in mind, my car is NOT an SPL rig, and I am not claiming it's incredibly loud, just that it's balanced.