[Richard2112]

Truck audio is a tricky subject because it really depends upon what a person likes to hear coming from their system. It's true that cab corners do not make the best enclosure but generally speaking, there are no areas of a car or truck which (by themselves) are suitable for good quality sound. There is a reason that speaker enclosures are not made of sheet metal.

And it is true that one does not really want the sound of a forward cone excursion to resonate throughout the sheet metal as it transfers sound easily and throws a large amount of audible flotsam into the listening field.

The reason we accept this is because there are few options otherwise or we have become accustomed to this as the way it is or should be.

A large enclosure does indeed help with mid/bass clarity but any enclosure at a auto speaker is a significant improvement over sheet metal.

Good quality speakers are often made of a non-directional material such as (mdf) then covered with a veneer for visual appeal.