First time builder question

[MPM]

I will be starting my first project soon. Have decided to go with

http://www.tnt-audio.com/clinica/bfb_e.html

to keep it simple. Its recommended that your internal dimensions need to be different. My question is how much different? To get 45 liters I've come up with 9 1/2" x 10" x 30". Focusing on the 9 1/2" and 10" dimension should I separate those two more or is the 1/2" difference adequate?

[MPM]

Is it bad to bump your own thread? I hope not.

[BillFitzmaurice]

You don't want any two dimensions to be that close. You also don't want to exceed a 3:1 ratio of one dimension to another. Model your design in WinISD and it will give you the preferred dimensions.

[Jennice]

I recon that the identical dimensions will cause a concentration of the standing wave problem (is that correct?), but why shouldn't there be more than 3:1 ? This would go against the design of many floorstanding speakers?

Has anyone tried such a speaker? How does it compare to a commercial one, say the B&W 309 floorstander?

I also considered this driver, but maybe supplemented with a super-tweeter at a first order HP filter, starting fairly high. (anyrecommendations?)

IF needs be, one could supplement it with an active sub. Again... comments welcome.

Jennice

[BillFitzmaurice]

You don't want to go longer than 3:1 so that it doesn't turn into a resonant pipe- unless, of course, that's the intent. Floorstanders that aren't designed as resonant pipes are usually subdivided internally to keep the longest dimension as desired.

[Timn8ter]

Will you be using the FE207E in place of the 204?

[MPM]

Hey Tim, I haven't made my mind up yet on the 206 or the 207. Most likely will be the 207s. Since I'm limited on space they will do double duty as my main speakers for my home theather. Provided they work good in that position I'll probably build a center channel and some surrounds with the same type speaker. My next project will have to be a sub that will compliment the 207s but thats for another thread.

[planet10]

Originally posted by Jennice
I recon that the identical dimensions will cause a concentration of the standing wave problem (is that correct?), but why shouldn't there be more than 3:1 ? This would go against the design of many floorstanding speakers?

As one dimension starts to get significantly longer than the others a simple BR turns into an ML-TL and the BR tuning is no longer valid.

dave

[MPM]

As it stands right now my wife has helped me make my decision on the dimensions of the speaker. She doesn't like the look of a thin floor standing so I'll have to make the speaker shorter. Now I have to make a stand to match that she approves of also. Atleast she is approving these hobby projects. It took an ant of congress to get her approval for any money spent on the racecar.

Thanks for everyones help.

[Tim Moorman]

No reason to allow the dismissal of long and thin to keep you from getting the Fostex up to seated ear height (around 33 -36").
You can artfully run the sides down to the floor allowing the box bottom to be suspended off ground, or build a separate false bottom sealed from the rest of the enclosure. Just make sure it is non-resonant(sand).

Many ways to keep height appropriate for the task without separate stands unless you like that look.

Tim