When I was referring to BLH, I was talking about a horn loaded rear wave that should be corner loaded to get any real extension. These tend to have greater bass output. I realise that the short small opening horn typically found on BLH's and almost all FLH's that are designed to be placed farther into the room (typical "audiophile" regulations ) aren't really any more efficient in the bass than any other type of box. I do find the actual sound to be typically a bit different, though, so I suspect there's something going on that makes a difference between the different type of bass boxes, but don't ask me what, as I'm not any kind of engineer. I just listen. Maybe I haven't listened to enough variety yet. I'm always open to people sending me (or stopping by with) different speakers so I can broaden my experience.

Dave