Horn formula ?

[Bernhard]

Hi,

how are those horns called which are used in the big horn arrays from Avantgarde acoustic (?)

I think everybody knows which ones I mean, the round coloured ones, in three different sizes mounted together.

My question is - I believe all have the same shape, just different size - , what is the formula to calculate the curve ? are they simply hyperbolic ?

Bernhard

[bhg41088]

hornresp

[GM]

Looks like a Tractrix which are truncated hyperbolic horns, ergo don't load all the way to the mouth's Fc, though its technical Fc is per whatever its length + end correction dictates. In general, the horn loads down to ~1.414x the mouth area if long enough and with the right size throat.

Am = ~((13560/Fc/pi)^2*pi)/4

At = 2*pi*Fs*Qes*(Vas (ft^3)*1728)/13560

then:

x = a * ln((a + sqrt(a^2 - r^2)) / r) - sqrt(a^2 - r^2)

where:

x = distance from the mouth of the horn
a = radius at the mouth
r = radius at distance x from the mouth

GM