What effect does the sub box shape have on volume and sound quality in general? Most dual sub set ups that ive seen have the wide boxes that are barely a foot deep. by comparison, some bass tubes that use similar sub and amp specs sort of sound better and louder, but of course i may be too subjective.

In any case, if there are some benefits, can i simulate a round tube by making a rectangular box? Since i don't want to mess with the stock mounting of my CD changer, im thinking of making a deep box, maybe 15" internal depth, and either install it between the changer and right footwell, or sideways behind the seats like a round tube.

I dont have a very large budget and since i dont compete in shows or anything im pretty much a DIY guy.

Thanks in advance for your comments and suggestions.