Narrow Dallas II/III blh with 4" full ranges

I have some spare 4" full ranges in my hands. I have the plans for Dallas 2 and can plot the curved Dallas 3 out of it. I have a friend with CNC and some 18mm mdf at hand as well.

The question is rather than building the actual Dallas 2, Can I keep all the dimensions except for the internal width of 280mm and narrow it down to 162mm. I can keep all the other dimensions intact.

Will the 4" will have a powerful enough back wave to create the bass? Will the narrow horn will have an adverse effect?

I am going to cut curved slices and stack them on top of each other. I have a enough 18mm mdf for the narrow build. If I build the actual size, it takes about 16 slices and I don't have 8" drivers.

I want to do it with 9 slices and with 4" drivers. I will make the outer covering slices from acrylic like Atilsley did on some of his speakers for looks.

I have already built frugal horns and I like them. I am looking for different projects for fun!
 

zman01

Member
Paid Member
2011-02-04 11:35 am
Dhaka
Hi kodomo,

The Dallas II/III was designed for the Fostex FE206E/EN drivers; if you resize the cabinet for use with different drivers, it is unlikely that it will function as intended by the designer.

For ~4" drivers the FH3 does nicely - works with quite a wide range of 4-4.5" drivers, relatively compact (vs other horns), and sounds good. Other designs are most likely not this flexible.
 
Dallas II (there is no such thing as Dallas III per se -that was a modification made by somebody else & not an especially good one) was designed very specifically for the old FE206E; while you can simply cut it in half & shove a completely different driver into it, it will certainly not be anywhere near optimal, or performing in any way as Ron intended. That's why he did the Austin 126 / 166 designs (for the smaller drivers). I suggest you consider building a horn designed for your drivers, or something very close -you will almost certainly get better results.
 
I already built a frugel-horn mk3 with success, I htinks its very good. These are for me to learn to build, to hear different speakers, I then give them as gifts to my friends. I have also built open baffles etc. I have a main system that is a full blown 5 way horn I am very happy about.

I decided not to go through with this project. I will be trying to build a horn similar to oris 150 but with square throat and rectangular mouth and experiment with it. Then I will add a woofer below it for bass duties...

Thanks for the help :)