The return of the JBL 2226H parabolic horn

can you help me understand how the specs of a driver can make it more or less suited to a different shaped horn like hyperbolic or parabolic as you have said? up until this i thought a driver was suited for a horn loading or not , not that im completely understanding how or why one does fit that criteria yet but that was my understanding.

For a traditional exponential or hyperbolic horn you look for a driver with the following characteristics:

  1. Low Qes
  2. High Bl
  3. Low Le
  4. Low Mmd
  5. Strong cone

For a quarter wave pipe (and tapped horn and my parabolic thing) you want a driver with
  • Medium Qes
  • Medium Bl
  • Low Le
  • High Mmd
  • Strong cone

Why it is so, I really don't know, but I will get the cavalry 🙂
 
Im no expert, just an enthusiast, but it would seem the lightweight cone and moving mass could use the narrow CSA and increasily bigger air column to keep that motorforce in check, otherwise it could be w bit ‘hyper’ or indulge in excess?

While the other has a moving mass with momentum to keep it smooth, while probably a lower Fs and Qts combo for a lower FB potential and the lazy air column shaped for the deep pipe or BLH like air column shapes that suit it?

Its a really nice design. Convenient shape with the square inside a square, but tilted.🙂
 
For a traditional exponential or hyperbolic horn you look for a driver with the following characteristics:

  1. Low Qes
  2. High Bl
  3. Low Le
  4. Low Mmd
  5. Strong cone

For a quarter wave pipe (and tapped horn and my parabolic thing) you want a driver with
  • Medium Qes
  • Medium Bl
  • Low Le
  • High Mmd
  • Strong cone

Why it is so, I really don't know, but I will get the cavalry 🙂

You realise that Tom Danley's first tapped horns used the drivers that you list as being useful for horns.
 
Great news!

What are you going to call it?

Haven't decided yet.

The Optimization process turned out to be surprisingly simple after I mapped out the path. Now it's just to clean up some of the calculations and the layout of the workbook, and it should be good for use.

Note, with a simple tweak this can be converted to an approximated conical or exponential horn. Might look into that over the weekend.
 

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Haven't decided yet.

The Optimization process turned out to be surprisingly simple after I mapped out the path. Now it's just to clean up some of the calculations and the layout of the workbook, and it should be good for use.

Note, with a simple tweak this can be converted to an approximated conical or exponential horn. Might look into that over the weekend.

It is possible to change the area at two corners. And still be Hornresp compatible.
 
Doing it that way is probably going to introduce a few path length inaccuracies, resulting in the built horn having a slightly higher Fc than the Hornresp model predicts.

The key is to end up with a Hornresp model that has the same (or less) net volume than the box design suggests it should be. If you have a folded design that has the same net volume and path length as the corresponding Hornresp model, then it's likely the effective path length is going to be a little shorter, because each rectangular fold in the horn results in a slight shortening of the path.

That's the lesson that I learned with my POC2 build, which was designed using a simple centerline method for determining the path length. Net volume and path length matched the Hornresp sim, yet Fc turned out slightly higher than expected. Now I use the Advanced Centerline method, which produces measured results that are much closer to what the sim suggests they should be.
 
I think letting the actual Fc do what it will anyhow (within reason)and concentrating on the wall to wall standing wave vs pressure wave exits result in segments of (harmonic intervals) and folding to support a ‘stepped pipe expansion’ intervals of wanted LP of the phase in steps in sound towards the opposite origins will show what Harry Olsen might suggest. Kindof what ‘offset driver entry’ can support when used for the place it sits in the (middle) of The affective pipes ‘flow’ phase cycle vs straight length of physical pipe to a closed end making 3 parts into 2 -driver- 2 if interpreted as such a course phase inverter’.

But heres the reference for driver specs that might suit a pipe or a stepped horn version. (Your post in the hornresponse thread might be answered in here), I hope i get the link to function and helpful in cut/paste:



Elements of acoustical engineering : Olson, Harry Ferdinand, 1901- : Free Download, Borrow, and Streaming : Internet Archive
 
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