The higher "figure of merit" for a bass reflex usally makes it the choice over a horn for a reasonably compact bass guitar speaker. In the early 1970's there were some rock bassists using horns of compromised mouth size and path lengtb - if nothing else these little 8-12 cu.ft. horns with ~100hz mouths made a lot of noise in the upper bass to cut though the guitar and drum's din.

Small horns like La Scala, Peavey FH-1, etc exhibit a lot of distortion below their practical cutoff (this is one case where a vented back chamber may be of assistance)

For the blues/R&B I played, a 15" Karlson w. JBL D-140 had a nice solid sound - more so than reflex boxes - I actually had to cut the bass a bit on some stages.

Wayne - have you built short PI horns for bass guitar or do you find reflex more practical? Also - to the readers of this group - what have you built for bass guitar or organ use?

(my old standby is 2-2.8 cu.ft. reflexes from one sheet of birch plywood -light and can stack em)

Freddy