Has anyone installed 5 x 7 speakers in the rear panels sucessfully? It appears the standard for the rear panels is the 5.25 round speaker. If a 5 x 7 produces more bass than a 5.25 round speaker (assuming the same speaker models) it seems like the 5 x 7 would be a better choice? I've taken the rear panel off and the opened area where the speaker magnet goes is open across the entire panel, so it seems like a 5 x 7 would fit.