Danley BC series (BC215, BC415, BC218)

For example I couldn’t ever understand why the cross sectional area of the horn paths inside the box just before the opening were bigger than the cross sectional area of the opening. This is probably some super technical aspect of those designs that I obviously don’t understand, or maybe it’s not and it’s just the way they build them because it doesn’t matter much, who knows…

Anyway I became much more interested in designing the layout so the last parts of the horn inside the box both have a cross sectional area equal to that of just under half the size of the opening (which you can see, btw, roborg had also come to that conclusion if you study those pictures). That way it’s all just another fold in the horn. This actually gave space to add more folds inside the box. (As this somewhat contradicts a previous point I was making regarding losing a fold in return for easier driver loading, I should say that I hadn’t realised at the time because I hadn’t looked at the plans for so long but also that my general feeling when working with these ideas was that indeed achieving a suitable horn length is not a problem at all here. Also I was addressing PTSD and I would have got more into those details later on as I did mention briefly. So apologies for somewhat contradicting myself there) 

More importantly, all of these ideas came together in a perfectly reasonable and simulatable (if that’s a word) way and in a box size that was very friendly to a sheet of ply. I’m confident it would work in this arrangement and the sims are stunning. Perhaps it’s not as technically savvy as some may require it to be to meet their standards but that doesn’t worry me at all. As long as the physical model is translated accurately to the simulation software which as far as I can see, it is, then it’s worth building. Call it the non technical external ground guidance sub. lol

Having now read the patent, rather than just viewing an isolated image, it is now more apparent how the external surface increases the length of the horn; although I would dispute the claimed 1m extra. I couldn’t see a reason given for the reduction in area at the exit of the cabinet, so not an ideal horn.

However, I can’t think of any occasion at live events that I have been involved with, where this setup could have been used. There can be very few occasions where this design can be used to it’s full potential.

With regards to the claim in the patent that existing sound equipment does not take account of its physical surroundings, I can’t believe that they are unaware of Mr Paul Klipsch and his 1945 patent. The idea behind this design is not new.

Some of the technical information appears to have been lifted from Dinsdale’s series of 1974 Wireless World articles. Other claims are misleading and some information is technically incorrect.

Most of the supposed benefits of this design can be obtained with any loudspeaker by placing them against a wall, or in a corner.