18" Folded Horns

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   So you got me thinking...... 
Horn length of 277cm to S5 using the floor as a further extension to the horn. 
Suited to the usual suspects but better suited to the lighter coned drivers such as the Fane 18-1000. 
Outer dimensions are to your specification 1200*600*900 

This is one cab @ 2pi 
4 cabs @ 2pi
And then 8 @2pi cabs for a quick LOL

This is a sketch up that isn't 100% finished but the internal horn dimensions are 100% true to the sims just need to sort out a few external things. I see the access pannel invader/psycho style with the possibility of a heat sink to help the driver cool better. 

I have designed the horn path to be as smooth as possible with smoothed curves (it does have one 180* turn involved that cant be helped) I have also developed a throat adaptor that will be a mission to build without the use of fiberglass and a mould which is also not 100% desirable but completely doable. A more basic version could be developed but at the expense of sound quality i imagine (whether this is audible or not is a different question). The throat adaptor is much the same as a letter box but giving a more even cone loading with an octagonal entry that turns 90 degrees in the first 15cm of horn.  

And here is a comical representation of the horn path using cute red arrows.

I would love feed back on this type of thing as in my eyes the throat adaptor (best seen in picture 2) will give better controle over the entire surface area of the cone making it act more like a piston. The smoothed horn path i believe will help make the design sound smoother rather than just hearing air move/chuff.

Squeezing the extra horn length in to the cab in this way was an idea spawned from a plan i have of a tapped horn that i have no further details than this picture :

This is to make the driver work in the same ways as a piston with no squeeze of pressure with the driver facing a flat or offset wall straight infront of the driver as with most conventional horns, with some (in my opinion a lot) of energy bounced straight back through the driver creating strange pressure nulls and peaks within this 'compression' chamber meaning the driver wont be as musically controlled i my opinion. My adaptation should create far less negative reflections and deal with this problem with a minimal loss of acoustical energy. A basic law physics states that the angle of incidence equals the angle of reflection and so i have drawn you this :

This is surely taking energy from the cone and making the system more inefficient? 

The adaptor is a perfectly octagonal 90 degree turn creating the first few centimeters of the horn with the begging of the horn measured from the octagonal entry. 

Please some one educated tell me if im going wrong or if more explanation is needed, iv had a few beers so i may be babbling shit.  