Horn Expansion Questions

[sts9fan]

Hi
I have just rescently been thinking about horn expansions and I have a few questions. The first has to do with speakers that have each fold with parellel walls, no angles. What are the ways to calculate the folds? Do you take the type of curve and take diameters along the 3d shape? So if you have seven folds take seven diameters spaced at the same ratio as the fold lengths?
The second question is a request for literature. Can anyone point me to good books on this topic?
Thanks
Kris

 

[hm]

Horn expansion

Hello,
may be you think about an geometric "horn" more an opposite TML.

you can get the data like this:
Calculation of expo horns

If you have AH, AM, l,
k still lacks the flare rate:

ln (AM / AH) / l = k

so you can see the surface
each point out (Al):

INV ln (l * k) * AH = Al

l m, AH + AM + AL in square meters

By Al e.g. m in width and divide
you have the distance in meters

AH = Horn throat
AM = Horn mouth
k = flare rate
l = length


Lengths and flare rate VALUES

K VALUES:
0.37 ~ 10 Hz
0.55 ~ 15 Hz
0.7 ~ 19 Hz
0.9 ~ 25 Hz
1.1 ~ 30 Hz
1.3 ~ 35 Hz
1.48 ~ 40 Hz

About an octave above k plays the horn,
if the length matches. At BL horn lengths
over 3.4 m, you get a suck out
below 100 Hz

4/lamda lengths VALUES
3.4 m ~ 25 Hz
2.8 m ~ 30 Hz
2.4 m ~ 35 Hz
2.1 m ~ 40 Hz
1.7 m ~ 50 Hz
1.4 m ~ 60 Hz

Most of my horns open
the last~ 75 cm (look ALPHORN)
with a double or triple k,
to get a better mouth+room
crossover.