I know you stated that you already had tower speakers, but this is what I went with from Aerial. Sorry for the low quality pic, it was all I had.



Assuming that you have the Rad-a-Cage tower like mine, you will have an issue with the Areial clamps since the rubber inserts only go as small as 1 3/4", and our tubing is 1 5/8". I took a length of black 1 1/2" ABS plastic pipe and cut it to the width of the clamps and then cut it length wise in half. The two pieces snap over the tower making the diameter larger. The black ABS blends in nicely with the black rubber inserts making them look like one piece. By the way, I ended up moving the speaker/light bar to the forward tube. They looked and fit much better.