Exponential Ports!!!!

[Cloth Ears]

Venki,

I haven't read all of this site (http://www.haliaetus.com/va/haliaetus.html), but I'd think you'd be looking for a jet shape,rather than a horn shape. And I'm not sure if efficiency is increased. But you can play louder through the same sized port due to decreased turbulence.

[Relax]

So what woudl this enclosure theoretically do with a single JBL GTI.

http://manuals.harman.com/JBL/CAR/Bo...5GTi_rev_f.pdf

if I scaled it up to this:



The lines represent the shortest and longest lengths of the horn? or port in inches.

and the numbers in the boxes are the area in inches square of each chamber.

Heighth can be anywhere between 17-19 inches, if that helps get a big SPL.

Then the question comes on how to port the sealed sections. I want pure SPL so I was thinking it needs to be ported at the frequency when the front and back waves add totally. But I don't know how to figure that out...

Can anyone tell us how to model the exponetial port in winISD, or does it require hornresp or soemthing?

[Volenti]

The people who told you that the horns are too short are right, what you end up with is closer to a bandpass enclosure than a horn, that doesn't stop it producing bass, but it does stop the acoustic gain that you would get from a properly sized horn.

If you want spl and have the space build a big bandpass enclosure, I took the liberty of modeling you an example; (see attachment)

I could use hornresp and model that design but I can gurantee it won't match this bandpass design for pure spl.

[edit] don't forget to add ~15db to that model to account for cabin gain

[Relax]

WHats killing me is that this enclosure does killer bass for my ten inchers. I have 2 infinity 10s that just pound, hitting over 126 db with 230w a piece. I just don't know how to scale it or even model it.

I am gonna try hornresp.

[venki]

Got the link is it the "Big Fun Horn"

http://kosat.consultit.no/~ketil/low...t.html#HD_NM_6

{Edit]
another one

http://kosat.consultit.no/~ketil/low...LFUN/Size.html (look for compromise )

Venki.

[Rademakers]

The link seems (to me) to provide you with the theory to calculate a free space (4 pi) horn. The section under compromise tells you how to calculate those numbers to a typical domestic environment (smaller than 2 pi).
The author also states not to care about a flat frequency response because the room interactions will cause interference anyway (this is true). For both ways (flat response or not) things can be said, I would see this as a personal choice rather than to be absolutely true or false.

The interface/layout of Hornresp is often thought to be slightly difficult (the DIY Wiki should overcome this). However it seems to be easier as the (hardcore) method used by the designer of the BIG FUNnel

Wkr Johan