Scaling a horn

[FJF 10+ year member]

Hi, folks. I'm thinking of using an Earthquake SWS-8 driver in an under-seat install. The plans for a simple horn are in the manual. Please have a look. They show a 3x10x10 enclosure. I need a 3x8x12 enclosure.

My question is this. How will the mouth of the horn need to be scaled as per the new dimensions?

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[FJF 10+ year member]

I called Earthquake hoping for some help. Spoke with a very nice man who had no idea what he was talking about. He asked for my number and said someone more knowledgeable would call me back. No one called. I sent them an email, as well, describing the constraints and asking the same question - how should the mouth of the horn be scaled relative to the size of the enclosure? No reply. So you guys are my only hope.

 

[brian84corvette 10+ year member]

it dont look like much of a horn design to me but what do I know ....

if for some reason I decided to build something that looked like that - and needed to change the dimensions

id put the port on the 8" side and make that angled baffle thing about 1" longer to make up for lost sq" since its smaller than origonal design.

looks like a slot ported box to me but with the slot port just angled up.

 

[FJF 10+ year member]

Thanks for the reply. I should have mentioned that the mouth would be on the 8" side of the enclosure.

Really, I'm hoping that someone with a modeling app can give the dimensions. I can model a sealed or ported box, myself, but this enclosure is out of my realm of expertise.

 

[Jroo 10+ year member]

I agree that doesnt look like a true slot port to me. You also have the same box size for the port vs. the sealed? Have you tried to put that in a box program to see how close or how far off the box sizes from earthquake are? Also are they saying that 6" is a free air and doesn need a box since they dont list one. I would be interested in 2 pairs in front of each seat if the box is small enough and these actually produce decent midbass.

 

[FJF 10+ year member]

Have you tried to put that in a box program to see how close or how far off the box sizes from earthquake are?

I modeled a sealed box. Earthquake's dimensions are smaller than optimum, but not horrible. Theoretically it may result in some midbass emphasis, which isn't necessarily a bad thing. I'd still love to explore the possibility of a horn, as per the manual, slightly scaled to fit under the seat of an Evo. Anyone?

 

[VWBobby 10+ year member]

I agree, its not much of a horn design, but the angle of the port will help amplify the sound slightly. Kinda like yelling into a megaphone compared to cupping your hands. It should give you a little low freq. extension and make the driver more efficient with the power its given. A small properly designed/built enclosure can make a small driver like that put out a lot of sound for what it is.

 

[FJF 10+ year member]

It should give you a little low freq. extension and make the driver more efficient with the power its given. A small properly designed/built enclosure can make a small driver like that put out a lot of sound for what it is.

That's exactly what I'm hoping for; I just need to know how to scale the thing.

 

[ciaonzo 5,000+ posts]

Felix, I think this is the formula you need.

Plucked from this page. ------> Horn Size and Shape - Theory

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[FJF 10+ year member]

Thanks a lot, Shane. Much appreciated.