An easy to build classic horn?

[dabbler]

This is just for fun really. I have a pile of foamcore sheets at home and was thinking of making some large horns with easy to build profiles, like the altec mantaray horn.

If I dont like it I can toss it, no harm done. Any other easy horn designs out there that would be worth a try? Up to 500mm (20 inches) wide and deep would be ok and 600-700 hz crossover would be nice.

[revintage]

fabrication1

Can also be made rectangular. The templates is easy to get from HR.

[dabbler]

Hi Revintage, not sure where HR is?

I'm also thinking something like an 8 petal conical could be easy to make. Anyone have experience with such horns? Any programs available for modelling?

[dabbler]

I think i'll start very basic and work my way up: A square conical horn. Is there a quick formula / ratio for calculating cut-off?

I'll smooth the throat transition with some putty...

[revintage]

Use HR=Hornresp! It also has templates for four and up petals. You should also use Hornresp to model the horn whatever flare you want, Tractrix, Expeonential etc, etc. You get the templates after you have modelled the horn.

[dabbler]

Ah okay thanks. I did try hornresp but had no idea where to start. Can't see anything on conical horns or petals etc. That GUI is for smarter chaps than me!

[revintage]

Without the flares and templates you can forget about building the horn. But if you decide how you want it, Fs, At(driver-area), type(Tx, Exp, etc) , number of petals(from four), I will make it for you. Go for a square Tractrix!

[Brett]

Originally Posted by dabbler

This is just for fun really. I have a pile of foamcore sheets at home and was thinking of making some large horns with easy to build profiles

Why not just conical then?

[dabbler]

Originally Posted by revintage

Without the flares and templates you can forget about building the horn. But if you decide how you want it, Fs, At(driver-area), type(Tx, Exp, etc) , number of petals(from four), I will make it for you. Go for a square Tractrix!

Thanks for the help, I had a look through the HR help manual and it makes sense now, so I should be able to get something happening on my own! I will eventually build a tractrix and le cleach but I will start with a square conical, simply because it is easy to build with stiff foamcor.

It seems that cutoff frequency cannot be entered for a conical horn (F12). Why is that? I can enter it for tractix and le cleach without a problem....?

[revintage]

Did you really check the conical horns frequency response on/off-axis? Constant directivity is useless for high-or mid-horns. The low end drops early which means you have to make it very big to go down to your prefered XO-point.