Curves

People have different opinions on the subject, it is very much a question of wavelengths involved and geometry of the folded horn part in question.

Given you are talking very large wavelengths relative to bend radius and length I would be inclined to say the extra pain of constructing smooth deflectors that do not resonate under the high internal pressures of a scoop design at high volume is not worth the trouble. I would personally go no farther than straight pieces of wood as corner deflectors at the top horn 180 degree bend because if nothing else they will add some bracing to the design. The re-design at the throat is almost certainly not worth the bother (in my opinion and based on nothing but my thinking!) 

Ok, thank you for the replies. Layering a few small curved sheets under the throat could be a chore for sure. From reading older posts I understand the negative expansion in this particular cabinet works and I see that the actual distance between the back panel and the last expanding piece may be at maximum distance otherwise choking would be the result. I could make the back deflector smaller or course but yes it will still have negative expansion. Are there any other free plans out there other than Hogs and Supers that would give Wardrobes a run for their money with PD's? Now i'm really stirring up the pot here because i'm not caught up on recent posts on modded or free plans...