DIY Back Loaded Horn - Dallas III for Fostex 206E

[jasonlky]

Hi,

Just want to share my DIY Horn speakers based on the Dallas III and Fostex FE206E. You can read it here. Tell me what you think....

Jason

[ronc]

Add 1-4 ohms series resistance to taste.

ron

[jasonlky]

Hi Ronc,
Thanks for the design. The speakers are really good and as long as I am off axis with the speakers toed out, I don't notice the shout inherent in these speakers.

What does the 1-4ohm resistance do?

Jason

[Cal Weldon]

Nice looking horns Jason.

[hm]

hello ron,

is the thickness of the side walls enough ??

nice work, good looking

[ronc]

is the thickness of the side walls enough ??

Based on the spacing of the internal supports, yes. However more bracing would be better.( Texas sayin " if more is better then too much is enough)

I ran the side loading sims on a structural loading program that was modified from a building enclosure program
that was altered for internal pressure fluctuations. (blow into a square box and measure the deflection of the sides)

What does the 1-4ohm resistance do?
It will bring up the LF response by raising the Qes which in turn raises the Qts. With the efficency of the 206/Dallas you will be hard pressed to notice any difference in efficency.

Again, tune to your personal desires.

ron

[ronc]

I just noticed in your pics the wires hanging out from the driver flange.
ANY leaks in the flange to baffle surface will affect LF performance. The driver flange should be totally sealed with something on the order of silicone sealant.

ron

(the hardest thing you can do is to make something simple)

Now I am not sure if the Dallas III was actually designed by Ron himself

Yep!

[jasonlky]

1. I will try the 1-4ohm resistors and report back as to what works for me.

2. The speakers are all sealed up so there is no way for me to add additional support/bracing unless I cut it open.

3. Yes the pictures do show that the wires are stickin' out and there is no proper seal. That said I very satisfied with Well, I have not installed the binding posts and I have also been asked to try the Coral 8A-40 in these cabinets. Once I have done all this, I shall seal up the cabinets.

4. I guessed that Ron did not design the Dallas III, but after cross referencing the measurements with the Dallas II, all measurements seem to line up. What I am not sure about is if the radiused corners will change the parameters and this the sound all that much....

Jason

[ronc]

I guessed that Ron did not design the Dallas III, but after cross referencing the measurements with the Dallas II, all measurements seem to line up.

I believe i did, unless it was a drug induced flashback (happens sometimes). My mind is still strong, however as i get older its more analytical and i spend much more time doing the actual math/physics and less dreaming, Maybe there is a downside to getting older, you lose imagination.

ron

I have also been asked to try the Coral 8A-40 in these cabinets.

I designed these cabs specifically for the 206, i cannot garrentee the results with any other driver.

[TerribleT]

Nice work. The Dallas design is beautiful. I have a pair of 206Es and I was considering building the Sachikos. Does anyone out there care to comment on the Dallas III's design versus the Sachikos'?
Regards,
David