Where to start for back loaded horns

[torea]

Hey all, first post.

I've been recently fascinated with back loaded horns. The look em is just awesome. I'd really love to get into making some of my own. But I feel like I'm getting swamped with information. I've found a few articles on them, and I've tried to digest what's been said in some of the threads here, but in the end I always end up scratching my head.

So, where would be a good place to start? Do I need to know a ton about other speaker cabinet styles before I can really get into back loaded horns?

I'm very new to speaker building, having some fun building cabinets for Leslie speakers, and I'd really love to be able to design my own speaker cabinets.

Thanks!

[hm]

Hello,
look my HP.

here a simple guide line for construction:
Calculation of expo horns

If you have AH, AM, l,
k still lacks the flare rate:

ln (AM / AH) / l = k

so you can see the surface
each point out (Al):

INV ln (l * k) * AH = Al

l m, AH + AM + AL in square meters

By Al e.g. m in width and divide
you have the distance in meters

AH = Horn throat
AM = Horn mouth
k = flare rate
l = length


Lengths and flare rate VALUES

K VALUES:
0.37 ~ 10 Hz
0.55 ~ 15 Hz
0.7 ~ 19 Hz
0.9 ~ 25 Hz
1.1 ~ 30 Hz
1.3 ~ 35 Hz
1.48 ~ 40 Hz

About an octave above k plays the horn,
if the length matches. At BL horn lengths
over 3.4 m, you get a suck out
below 100 Hz

4/lamda lengths VALUES
3.4 m ~ 25 Hz
2.8 m ~ 30 Hz
2.4 m ~ 35 Hz
2.1 m ~ 40 Hz
1.7 m ~ 50 Hz
1.4 m ~ 60 Hz

Most of my horns open
the last~ 75 cm (look ALPHORN)
with a double or triple k,
to get a better mouth+room
crossover.

[torea]

Thanks for replying!

Originally Posted by hm

...so you can see the surface
each point out (Al): ...

...AH = Horn throat
AM = Horn mouth
k = flare rate
l = length

Like I said, I'm very new to this so I wanted to make sure I'm understanding correctly: Al=area of the length, AH=area of the horn, AM=area of the mouth. Is that right?

About an octave above k plays the horn,
if the length matches. At BL horn lengths
over 3.4 m, you get a suck out
below 100 Hz

4/lamda lengths VALUES
3.4 m ~ 25 Hz
2.8 m ~ 30 Hz
2.4 m ~ 35 Hz
2.1 m ~ 40 Hz
1.7 m ~ 50 Hz
1.4 m ~ 60 Hz

What do you mean by suck out? The bass is reduced?



Thanks again!

[rjbond3rd]

Easiest software to start out with is AJHorn:

AJ-Systems

[torea]

Originally Posted by rjbond3rd

Easiest software to start out with is AJHorn:

AJ-Systems

Looks interesting, but will it run on a Mac? I've really got to get Windows/BootCamp installed and running on my computer, but at the moment I don't have access to any Windows computers.

[GM]

Originally Posted by rjbond3rd

Easiest software to start out with is AJHorn

Really? Not HornResp?

GM

[hm]

Hello,
AH= horn beginning
AM= horn end
AL= the length which you need for construction,
folding etc.

Hiifi horns are allways to small and short so you get dips and peaks.

look the impedanz of horns, if someone published it like me.
If you don´t know what an oktave is, read before building

[hm]

here for understanding,

http://www.lenardaudio.com/education/07_horns.html

[rjbond3rd]

Originally Posted by GM

Really? Not HornResp?

Hi GM,

AJ Horn is definitely simpler for me for BLH. Once the driver params are in the "library," you just specify rear-loaded, coupling chamber, mouth, length and throat. No summing of curves, and some of the geometry features are assumed (e.g., that you're building a "flat" constant-width cabinet).

So for me, the handy feature I need is that it generates a simple build-plan for the horn, in the form of a list of numbers (you enter the cabinet depth and it gives you the "width" along the curve plus cross-sectional area).

It does seem to model fewer factors (for example, baffle step does not appear to be modelled, and it appears to assume the driver and mouth are a point-source, i.e., not taking into account the offset between them into the summation -- but I am using version 5, and there is a version 6 with more features, and anyway, I could still be wrong about version 5).

I started using it in part because the Replikon guys were (and it seems, most German horn hobbyists). I haven't given HornResp a fair shake but will be doing so in the coming year.

[GM]

Greets!

Good to know, thanks!

GM