Sometimes a slightly provocative headline is necessary to attract attention. Please don’t take it too seriously. But it should be well known that the origin of my activities regarding horn development was dissatisfaction with these types of horns. Personally, I just couldn’t live with the fact that these horns consistently focus the sound extremely narrowly (beaming). There is more or less a very small sweet spot where you can experience the full spectrum of the music. If you move away from the sweet spot, the sound image collapse very quickly. What I have also noticed repeatedly as a negative aspect is that the on-axis listening experience is often very direct, tiring, or even annoying in the high-frequency range. As always, perception is subjective, and it may well be that there are people who explicitly like this. It is important to me to emphasize that I am not claiming that my opinion is the only valid one. Nevertheless, in this article, I would like to describe and also demonstrate with help of a BEM simulation why I have come to this conclusion and why I consider these horn types to be obsolete. Continue reading
Tag Archives: spherical wave horn
Progressive Expansion T-Factor Horns
In this post I would like to describe a method that I have been using since some time to get more flexibility with regard to different horn profile slopes. The fact that slow expansion profiles like the exponential or spherical wave horn provide very good loading but suffer somewhat with respect to directivity control inspired me to look for an algorithm that influences the given specific horn expansion function. I ended up with a modification of the well known wave front surface area expansion formula for hyperbolic (hypex) horns which is given by:
\tag{1a}S_z = S_0\cdot \left( cosh(\frac{m}{2}\cdot z) + T \cdot sinh(\frac{m}{2}\cdot z) \right)^2
\tag{1b}m=\frac{4\pi \cdot f_c}{c_s}
I will not go into more detail but with T=1 we get exactly the well known exponential horn for a two dimensional surface area expansion. This formula can also be used for the spherical wave horn with it’s assumed spherical wave fronts and will put out the same SWH profile already described on this site. Equation (1) is extremely flexible because when T \lt 1 an hyperbolic profile is the result and when T \to \infty the horn profile becomes conical. This is the reason why I switched to this formula as it gives me the flexibility to produce horn shapes with different slopes only by changing one parameter. Up to here nothing new but what if we make T a variable function that depends on a reference point somewhere on the horn axis z_{off} and the distance from or to this offset?
DrBA Calculator and BEM Simulation
DonVK’s second article deals with the verification of the DrBA spherical wave horn calculator and BEM simulation model construction. Only the round mouth spherical wave horn was initially used for comparison to published works. Additionally, the effect of adding a roll-back section or even more a merge of the roll-back section with the inner horn wall will be discussed. As already mentioned in the original patents, the continuation of the horn profile beyond the mouth plane has positive effects and leads to more even results.