I concur,this happens on my S horns in particular,because of the 2 corners 3 section horn,the last triangular volume for Vrc can end up needlessly large for a 10". For my jbl 15" however it tends to be just right :p

Thats why for small vrc woofers i prefer to try all the otherways too,such as my old first technique of going like the labhorn apart from the 90* change in horn flare expansion on the last folding.

http://homepages.paradise.net.nz/quadroph/digitor_files/image009.jpg

That way i didnt waste any space..but driver accessability its abit worrysome.

The S shape i prefer ,and try first :-) 2 CSX 10"s require ~50L or so which on my horn of 2600cm^2mouth 2.6m expo tends to not waste.

Im just debating whether to use the jbl or not,because a csx10" horn of same cutoff as jbl is 100L smaller

Cheers