Either brilliant idea, or exceedingly ignorant.

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Hi all. Please indulge me here. Is it possible to front horn load an already ported enclosure? In theory the port comes out in phase with the front in any properly designed box and greatly increases efficiency at fs. Why can not the whole kaboodle (driver front wave plus rear wave from port then be combined and fed into a folded horn? Would this not render an extremely efficient design?
 
I'm apparently extremely ignorable. I can however continue this conversion with my self until I solve it. Now I am wondering is not having the driver in a sealed enclosure prohibits its action as a pseudo compression driver, thus limiting its potential SPL in trade for extended LF?
 
Thanks , hangin in. I have seen variations on this so I know its not completely without merit. I always wondered why PWK did not vent the drivers right into the horn instead of sealing them. The K-33 for example works about as well used either way. There must be a phase or comb filtering dynamic that I am missing here, though it seems to me to be a no brainer best of both worlds possibility.
 
There is no reason you can't do this, but there are plenty of reasons for not doing it. #1 being that I don't think you can simulate it, so YMMV.

People do this all the time, it's called sticking the sub in a corner.

I guess we should ask what the driver and enclosure specs are...
 
Well, one of the issues is that at the frequency where the port is working best, there is very little output from the main driver. At all other frequencies the port does less and less +/- that center frequency where the port is tuned.

I'm not sure this is a big problem, but it will cause a change in the way that the horn is loaded, since there is a compression ratio effect at the throat where the driver enters the horn flare.

You could set that for 1:1 or less, but the horn effect becomes reduced somewhat.

It's an interesting idea, but likely ur not the first person to think of it, so that *might* be why nobody has published this method, the reason being that it might not provide any benefit, and/or have deficits that can't be overcome.

I don't think you get any output gain from it, but that is just a speculation.

_-_-bear
 
Funny thread. Yes of course you can do it, and it has been done. You cannot sim it in hornresp, but maybe in akabak. The more common approach is to do a ported horn where the vent exits independent from the horn, thus the smaller horn handles the higher end while the port fills in the low. These also overlap with bandpass horns. Check out the forums at speakerplans.com
 
Hi NEO Dan,

Post #12: "...I don't think you can simulate it..."

It should be possible to simulate a horn with sealed rear chamber in AkAbak, and then add a duct element in parallel to the driver.

Also, Fostex did something remotely similar?

Regards,
 

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Hi all. Please indulge me here. Is it possible to front horn load an already ported enclosure? In theory the port comes out in phase with the front in any properly designed box and greatly increases efficiency at fs. Why can not the whole kaboodle (driver front wave plus rear wave from port then be combined and fed into a folded horn? Would this not render an extremely efficient design?
A port is a Helmholz resonator, it requires a specific area and length for the size of the box to properly tune.
The horn starts with a small mouth, often not much larger than a decent size port.
A port iThe port tuning would be lowered by the horn, making it no longer contribute properly.
Ports can be put mid point (or so) in the horn, but placement is fairly critical for them to be effective.
For the most part, ports are just put on the front baffle of horn cabinets.

I made a ducted front loaded horn that works pretty well.
It uses a sealed compression chamber and ducts from the throat to the horn.

http://www.diyaudio.com/forums/subwoofers/217929-lab-12-domino-dflh.html

I spent more time getting it to work than any previous cabinet, and got a few less responses than your post already has :rolleyes:.

Art Welter
 
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