Betsy's kickin' it horn style

[brsanko]

I came across www.wildburroaudio.com and realized that someone was making full range drivers right here in Minnesota. So I decided to plug them into hornresp and see what they could do. The Betsy didn't seem to like horns all that much but the Betsy -K did ok. So I drew up some plans and will probably try them. The bass extention isn't really low (80hz) but they should mate well with a tapped horn. I didn't see the big dip at 150hz untill I was all done and could figure out the path difference between horns. I'll play with it some more and try to fix that but here is what I have so far.

 

[brsanko]

here is the autocad drawing.

 

[brsanko]

I suppose I should explain a little. The top right picture is the combined response of the front and back horn, while it looks terrible the smooth curved line is how hornresp models the driver without a horn (open baffle) if you compare the two graphs you can see the horn brings the response up relatively even (for a horn) across the board. As the real response of the driver is pretty flat when you correct for this you get a full range response from the horns. I wasn't sure if this was acurate so I've tried a few designs and it really seems to work this way. The bottom right is the maximum spl at all frequencies through the rear horn. As you can see it is capable of volumes of 100db+ from 30hz on up. So if your not afraid to use an eq or tone controls you could get some serious bass out of these puppies. Although the front horn does have some effect on this that isn't shown in the model. The top right is the parameters as entered into hornresp and the bottom left shows the cone movement at one watt at all frequenies. The other picture is a screen shot of the design as drawn up on Autocad if anyone is interested in the actual autocad drawing please email me.

 

[freddi]

cool - I tried to figure out a short BIB type

An externally hosted image should be here but it was not working when we last tested it.

one easy way out would be just to go open baffle and use the Goldwood GW1858 as a helper woofer - maybe with regular Betsy

 

[fwater]

I second that. Standard Betsy on 33" x 22" goes low and loud enough to satisfy many people. This is, of course, an assumption about tastes, but I'm a metal guy, and I can live without the helper woofer more than half of the time. One 15" or 18" would do the trick, in fact. Now lets see what can be done about Betsy's rather assertive personality...

 

[brsanko]

I realized I had somehow messed up on my measurements on my drawing and I wasn't folding my corners correctly so I redid the drawing here is the revised version.

 

[brsanko]

It's a little easier to see without all the measurements

 

[CLS]

In the end, I guess the difference in that bend won't affect the final result very much. (0.5~1dB, 2~3Hz sort of thing.... )

OK, I confess, that's only a "guess" from the limited experiences of playing with Hornresp.

 

[brsanko]

oh well made it easier to build it too. Besides my friend Doug with the cabinet shop won't build 'em unless he's confident that I designed 'em right.

 

[mightym]

Been lurking here, are these being built?

could the back horn be folded to reduce OA cabinet size?

John

 

[brsanko]

I am not currently building these but they are on my short list of designs to build. You could certainly fold the rear horn if you like, but I designed them to have the driver at ear height and the horn on the floor to reinforce the bass.