I've been toying with the idea of using a horn in a spl application (one note wonder, as efficient as possible) for a few weeks now..

Instead of a regular wall, with the woofers and port on the wall, me and a friend had the idea of using a horn, with the opening as the whole front of the wall.

It would be a front loaded horn, exponential, loaded with some sort of efficient pro-audio woofer, not the "horns" that have popped up in the car audio scene.

Apart from the difficulty of fitting a horn (around 22ft long for the woofer I'm thinking about, should be shorter for a very narrow bandwidth), any problem with using it in such a small space ?

Or any sort of other problems which would make such a horn useless for the application ?

i say try it might be a first ive never seen anything like it

size does matter

You could look into a folded horn, something like a LAB horn. Using a single 12 or 15" driver. When you go folded, you can gain alot of enclosure volume efficiency.

The horn that Dan Wiggins was using with the Tempest was a scaled up LAB (or Cerwin Vega variant), and was around 7-8 cubic feet externally (IIRC) and was pretty efficient and could be adapted to a car. I think it got down into the upper/middle 30's OK. The plans may still be on the net for it...

I'd definatly go for a ported back enclosure to go with that frontloaded horn !

hornmouth 10 times the size of the woofer-cone-area should do ,

I'm planning to do something simular with a 12inch Mayhem ... if the prediction of the calculating-program is right its going to be one LOUD mofo !

You could look into a folded horn, something like a LAB horn. Using a single 12 or 15" driver. When you go folded, you can gain alot of enclosure volume efficiency.

The horn that Dan Wiggins was using with the Tempest was a scaled up LAB (or Cerwin Vega variant), and was around 7-8 cubic feet externally (IIRC) and was pretty efficient and could be adapted to a car. I think it got down into the upper/middle 30's OK. The plans may still be on the net for it...

I think I may have somewhere the plans for a Cerwin Vega horn, I will have to look.

Folded is definately what I want, or I'd need a bus to fit it non-folded.

Having something that could extend into the 30's would be a good plus

I'd definatly go for a ported back enclosure to go with that frontloaded horn !

hornmouth 10 times the size of the woofer-cone-area should do ,

I'm planning to do something simular with a 12inch Mayhem ... if the prediction of the calculating-program is right its going to be one LOUD mofo !

Why enclose the rear of the speaker in a ported box ?

Thanks for the feedback so far

I'm not sure how well the horn would load into a cabin. You could use HornResp as a general guide on the horn dimensions and tuning.

the reason why is quite simpel ,

you prob understand the difference between 4th an 6th order banpass enclosure .

so now think of a front loaded horn as a 4th order bandpass , the small back enclosure gives a high upper tuning

,by porting the box you can narrow the band by tuning lower ,giving more gain in a small band as a result ....

maybe a double horn would be nice , I cant calculute that in a program but maybe it can be done by hand , making the backwave travel twice as far as the frontwave and giving both the equal amount of hornmouth area

Hornresp can model compound horns

Hornresp is what I used to simulate a small midrange horn but I haven't tested it yet.

Fingers crossed I'll have the time to build such a huge horn and I'll definately try it with the rear ported and sealed.

Now, to hijack my own topic...

I want to build my own flared port ends, only problem is I don't know if the flare is a simple radius or some sort of parabola. 12 inch tube flared to 18~20 inches sounds right ?

I want to build my own flared port ends, only problem is I don't know if the flare is a simple radius or some sort of parabola.

It depends on what style of horn you are trying to build. There are conical, hyperbolic, exponential, and tractrix (seems to be most popular in DIY community for horns), which are you looking for making?

*edit* Then again I'm not sure how well that works with folding it etc, etc...

I want to build my own flared port ends, only problem is I don't know if the flare is a simple radius or some sort of parabola.

It depends on what style of horn you are trying to build. There are conical, hyperbolic, exponential, and tractrix (seems to be most popular in DIY community for horns), which are you looking for making?

*edit* Then again I'm not sure how well that works with folding it etc, etc...

That big horn will be exponential or tractrix.

The flare question was not related to the horn question.

http://www.subwoofer-builder.com/flares-25mm.htm

That is what I want to build, only I'm going to do the flares on a mould, out of fiberglass. Haven't seen an aeroport live, so I don't know if the flare is just radius (like in the link), or a parabola.

EDIT : re-read the link and it's just a simple radius. Time to start working on it.

I've made flared ports this way out of 125mm (5inch) PVC with 5cm(2 inch) flares,

and must say they work very well !

I personally believe that horns get loud. I had a pair of EFX 10" in a Pound That Sound Hybrid Horn

And I was never able to get those subs louder than they where in that box. My GF always gave me Crap for shaking everything thing in her store when I would come to pick her up......

And when I get the cash to redo my system again I am putting the Subs in a Horn.