So I am seeking a recommendation for a powered subwoofer whose sole purpose is to reproduce the sound of distant thunder rumbling. Hoping to find something <$500, age, appearance totally unimportant as it will be not be seen by anyone. It will be placed on a second level deck, the effect is intended for people walking on the ground below and around the deck. Since as mentioned the goal is for the sub to reproduce distant thunder, I dont think I need a huge amount of power. It will sit in a deck approximately 25' x 14' with one 25' side (opposite walkway where people will be) enclosed by home and the other sides only with 2ft wall with railing. Thanks!