Why not a round Tractrix horn

[ClaudeJ1]

 

Going a step further, there is a range of frequencies where a straight-walled square cross-section horn will have the same radiation properties as the circular cross-section with the same flare angle. This is because the wavefront (not the horn) stays circular. The calculated area of the horn as a function of X will be different, but the wavefront area will be the same. If that is the case, then can the square horn be considered conical in this instance?

 

 

Does nobody want to bite on this one? Maybe I can ask it another way: Is it the shape of the horn, or the shape of the wavefront that dictates its definition?

 

It all depends on how you "squeeze" it coming out of the driver. Phase plug, no phase plug, length, shape, flare, etc. But you know all this. Why the quiz?

[ClaudeJ1]

Mr. Chief Bonehead, how did you decide how to constrain the design...if I might might ask?  Is there something special about the width, height, and/or depth of typical applications in pro cinemas, or was it the lowest freq. where its polars begin to shift increasingly outwards?

 

Interesting plots. 320 Hz. is where I crossed mine to the Quarter Pie Horns underneath the K-402's. They sounded just gorgeous that way. Tweets and subs were just icing on the cake above 5Khz. and below 50 Hz, respectively. 

Edited December 16, 2014 by ClaudeJ1

[johnnydrama]

This is my favorite horn on a Klipsch speaker. Hence why I deploy XF-48s at home and XL-12s at the office. The dispersion makes setup much easier and the sweet spot much larger. It's also not as harsh

[Chris A]

Interesting plots. 320 Hz. is where I crossed mine to the Quarter Pie Horns underneath the K-402's. They sounded just gorgeous that way.

Thanks for that -- it's pretty important info--in the scheme of things.

 

Chris

[ClaudeJ1]

This is my favorite horn on a Klipsch speaker. Hence why I deploy XF-48s at home and XL-12s at the office. The dispersion makes setup much easier and the sweet spot much larger. It's also not as harsh

True, but we are talking about a 300-400 Hz. crossover situation, not 3-4 KiloHertz, which is 3.5 octaves higher and much easier to control.

[Chris A]

Do all horns with straight sides follow the conical expansion?

 

  BTW: the equation for a conical horn (Beranek, Olson, et al.) is:

 

                   S = S₁x²

      

where:        S  = the area at the horn mouth

                  S₁ = the area at the horn throat

                   x  = the length of the horn from the throat to the mouth

 

The straight-sided portion of the K-402 horn area expansion formula doesn't follow the conical equation.  I've measured it.

 

Chris

Edited May 9, 2016 by Chris A

[DrWho]

Here is the equation I use for a conical horn:

https://www.grc.com/acoustics/an-introduction-to-horn-theory.pdf

 

St and Xo are independent free variables and cannot be consolidated outside the brackets. Regardless, the conical equation is not applicable here because it only predicts total power transfer, and the assumptions behind it don't hold true in nature. Although we gain some insight from equations like the conical, they still don't accurately describe the real world behavior.

[Chris A]

BTW: the K-402 area expansion equation doesn't follow that equation, either.

 

Chris