Its probably the latter Jerry. At these price points it is very tough to get best of both worlds without a sub. Budget bookshelf speakers just don't have the bass extension, that is why you see certain frequencies bumped to give off that illusion (fullness). You will find a lot of budget bookshelf speakers that roll off below 100hz, have an excellent frequency response from 100hz and up. Hence, they will need a sub to sound balanced. Hitting certain price points there are trade-offs. There is no way around it. You will likely have to spend more money on the speakers themselves when not using a sub. The Ascend Sierra-1 is another example that comes to mind, but it is around $500 more than what your budget permits or willing to spend.

I’m armed and I’m drinking. You don’t want to listen to advice from me, amigo.

-Max Payne