bassboy
Ex Member
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Hi J, I saw some of your posts in the other forum and some people seemed more intent on questioning the original design of the WO than answering the question you asked. People that should know better, but they have their own stuff to sell, I guess.
I did a google search on exponential port and surprise, surprise, I didn't find much. Maybe people know about them and are calling them something else, but there's not too much info on that particular search. These are my observations based on listening to a WO and conventional horn theory. Let me begin by saying I may be completely wrong and welcome comments and critisism.
The WO is NOT a horn by definition, at least not when used as a subwoofer. Then gentleman in the other forum was right, by definition, this thing should not be able to go any lower than about 70, and that's if you stick it in the corner. If you stick it in the middle of the room as a coffee table, it shouldn't be able to go lower than a few hundred hertz. That would mean that when we cross it over at 80, we should be theoretically listening to absolutely nothing. Is that the case? Of course not. I'm just guessing here, but I think most WO's are flat down to at least driver fs, regardless of room position.
So what is going on? I have read at least 3 times in different articles about bass horns that until they get about 5 feet long they are not working as horns at all. Not once did they mention what was going at at this length, the general consensus is just that it needs to be bigger. This is why I believe Steve only scales in one dimenstion. To elongate the horn (flared port, exponential port) too much would make it act like a horn, effectively making it useless as a subwoofer. I can't prove that and I certainly am not going to build one to prove it won't work.
The flare contour or expansion rate does not seem to matter nearly as much as a real horn. For example, Steve's corner horn is also much too short to theoretically do what it does, so it must also be a flared port, although it increases dramatically faster and ends with a much larger mouth.
So what is important? In my opinion, based on absolutely nothing, it appears that a flared port should begin with a throat roughly the same as a corresponding real horn would have. It should increase in surface area and length, to a length of not more than 4-5 feet and a mouth of no less than 5x throat area and I don't know about mouth maximum area but using the cornerhorns as a reference it should be able to get pretty big.
As far as porting this box, I do not think the gain will be worth the consequences. I believe that raising the low frequency of a subwoofer is a crime tantamount to murder. Just my opinion.
So please bring your critisms, as I would like to better understand this type of box. I know my theory doesn't make a lot of sense but remember that by traditional theory this box used as a subwoofer coffee table in the middle of the room should have close to 0db output.
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