hey all.
Would like to get people's opinions on a possible design for a 21" ported horn if you would be so kind....
A little history to the design, it all started when I read a thread about the Othorn. I vaguely knew it existed before, but had never really paid it much attention. However one bored afternoon I read through the thread and was much more taken by it, and by the reactions people were having about it. It seemed like it was a MUCH better design than I'd initially thought, much more worthy of attention than I'd realised, so I started messing about with the design a little, trying some different drivers and things in it (and imagining I might have time/money to build a big pile someday
)
However I've always been partial to ported horn designs and so had a quick mess about in Hornresp, thinking that I would see what I could do in a ported horn that was the same sized box and compare it to the tapped horn version. Using the B&C sw152 and a carbon coned 21" eighteensound driver (the ones I had been trying in the tapped horn versions I'd been messing with) I was getting decent results, as good as the Othorn, but nothing that blew me away or seemed like a big improvement as such.
However I read a a random article about B&C's newest driver the 21DS115, something popped up on Facebook or whatever, and on a whim decided to try it in the ported horn design as well, just to see what would happen......
....and thought that cant be right! That's significantly better than the Othorn, right across its frequency range!
However having checked my sums and looked at everything, double checking all my stuff it seemed that yeah, this seemed to be a bit of a magic combination.
Playing about with it and refining it a bit, I was able to shrink it down to a box that was a chunk smaller than the Othorn, shaving 40 or 50 liters off of the overall volume of the box, not having quite such a compression ratio for the driver saving a little pressure on the cone, while still having what looked like a much better response!..... (my design in black vs Othorn in grey).
After playing about a while and trying to work out how to fold it into an actual box, I came up with something like this......
with the idea that the horn path would curve round to the right after coming through a Martin style letterbox throat, the driver baffle would have holes cut into it to open it up int the two central areas, and the port would be a long port off to the right as shown. This then turned into wood would look like.....
I've had the design sitting unused for a year or so, I'm hoping maybe over the summer if I have time to make some prototypes and mess about with it. However I was reading some testing info posted on the "speaker freakers" facebook group about different shapes of ported horns, and measurement showed that both the fact that my port was rectangular and that it had a bend in it would add distortion and port compression over an equivelent round port. So i reworked the design a little and added in 4 straight 4" round ports rather than the big shelf port......
The port done as 4 round pipes doesn't have the same cross sectional area, but it does then have the bonus of slightly improving the response as the 4 round ports take up a little less cab volume than the shelf, given the same overall cab size. Comparable cabs like the Void Trinity X and Nexus XL seem to have similar or less port area and seem to work ok, as do things like Martin's ported horn MLX and WLX subs, so I'm hoping it's still enough to work ok.
Just interested in peoples thoughts or ideas about the design in general, and specifically the choice of port method.
Kev
Would like to get people's opinions on a possible design for a 21" ported horn if you would be so kind....
A little history to the design, it all started when I read a thread about the Othorn. I vaguely knew it existed before, but had never really paid it much attention. However one bored afternoon I read through the thread and was much more taken by it, and by the reactions people were having about it. It seemed like it was a MUCH better design than I'd initially thought, much more worthy of attention than I'd realised, so I started messing about with the design a little, trying some different drivers and things in it (and imagining I might have time/money to build a big pile someday
)However I've always been partial to ported horn designs and so had a quick mess about in Hornresp, thinking that I would see what I could do in a ported horn that was the same sized box and compare it to the tapped horn version. Using the B&C sw152 and a carbon coned 21" eighteensound driver (the ones I had been trying in the tapped horn versions I'd been messing with) I was getting decent results, as good as the Othorn, but nothing that blew me away or seemed like a big improvement as such.
However I read a a random article about B&C's newest driver the 21DS115, something popped up on Facebook or whatever, and on a whim decided to try it in the ported horn design as well, just to see what would happen......
....and thought that cant be right! That's significantly better than the Othorn, right across its frequency range!
However having checked my sums and looked at everything, double checking all my stuff it seemed that yeah, this seemed to be a bit of a magic combination.
Playing about with it and refining it a bit, I was able to shrink it down to a box that was a chunk smaller than the Othorn, shaving 40 or 50 liters off of the overall volume of the box, not having quite such a compression ratio for the driver saving a little pressure on the cone, while still having what looked like a much better response!..... (my design in black vs Othorn in grey).
After playing about a while and trying to work out how to fold it into an actual box, I came up with something like this......
with the idea that the horn path would curve round to the right after coming through a Martin style letterbox throat, the driver baffle would have holes cut into it to open it up int the two central areas, and the port would be a long port off to the right as shown. This then turned into wood would look like.....
I've had the design sitting unused for a year or so, I'm hoping maybe over the summer if I have time to make some prototypes and mess about with it. However I was reading some testing info posted on the "speaker freakers" facebook group about different shapes of ported horns, and measurement showed that both the fact that my port was rectangular and that it had a bend in it would add distortion and port compression over an equivelent round port. So i reworked the design a little and added in 4 straight 4" round ports rather than the big shelf port......
The port done as 4 round pipes doesn't have the same cross sectional area, but it does then have the bonus of slightly improving the response as the 4 round ports take up a little less cab volume than the shelf, given the same overall cab size. Comparable cabs like the Void Trinity X and Nexus XL seem to have similar or less port area and seem to work ok, as do things like Martin's ported horn MLX and WLX subs, so I'm hoping it's still enough to work ok.
Just interested in peoples thoughts or ideas about the design in general, and specifically the choice of port method.
Kev
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