fostex 206 in 2.5 cubic foot box

[JimW]

I have a pair of 2.5 cubic foot boxes collecting dust, and was considering put a 206 in each of them. How would the work in a reflex enclosure? The boxes are 18 x 24 x 14 deep.
Thanks
Jim

[drongo]

Fostex recommend a 45 litre cabinet, so 2.5 cubic feet (approx. 70 litre) is much bigger. I think smaller would certainly be better.
Have a look at this http://www.tnt-audio.com/clinica/bfb_e.html

[MPM]

Check out the cabinets on this site. They have one about the size of what you want. The porting they use is the key.

www.fostexspeakers.com

[Dave Jones]

Originally posted by JimW
I have a pair of 2.5 cubic foot boxes collecting dust, and was considering put a 206 in each of them. How would the work in a reflex enclosure? Thanks
Jim

They would be boomy in the extreme.

In a sealed box that size, the speakers would be extremely over-damped.

You might be able to put some partitions in the box to turn it into a back horn. I don't know if they are a good size for that or not.

Assuming the inside height dimension is 22", you could put partitions in the box to turn it into a 44" tube. Add a 4" diameter port 6" long at the end, and you have a mass loaded transmission line. But it would have a 6 db shelf at about 300 Hz. To kill that, add 8 ohms series resistance. Use some polly fill stuffing, but not too close to the port. I did a quicky using Martin's worksheet. You can probably do better by tweeking around with it. See chart.

[Dave Jones]

Check this one out.

[Dave Jones]

Originally posted by Dave Jones
Check this one out.

Zport should be 41 inches. Note, this has 8 ohms series resistance added.

[Nelson Pass]

Originally posted by Dave Jones
To kill that, add 8 ohms series resistance.

About the time you decide to add that much resistance, you
might as well go to higher source Z and get the bottom end
out of the existing sealed box.