A sub is not an absolute necessity. You will be missing the big effects from movies and the lowest notes of instruments such as pipe organs, double-bass and other very deep instruments; and also the lowest harmonics of high/low instruments like cello and typical left-hand piano. But it is not the end of the world. Constraints are constraints and you have to live with them! \:\(

If you don't get a sub, you may want to consider the M3s, which have a slight bump in the bass.

See Mojo's signature