Advice on full range enclosure for 5.1 setup

[CDJ]

I plan to build small floor standing enclosures for a small room. I thought about designing a single driver loudspeaker using the full range 4” Fostex FE108Sigma (http://www.fostex.com/speakerparts/fe_sigmaseries.html). I plan to use these speakers in a 5.1 setup with a subwoofer with a 80 Hz crossover. Would it be worth the extra effort to make a transmission line enclosure over a closed box design? What Hz would I tune the enclosure? Whose transmission line formula is the best?

Thanks for your help,
Curtis

[planet10]

Originally posted by CDJ
[B]I plan to build small floor standing enclosures for a small room. I thought about designing a single driver loudspeaker using the full range 4” Fostex FE108Sigma (http://www.fostex.com/speakerparts/fe_sigmaseries.html). I plan to use these speakers in a 5.1 setup with a subwoofer with a 80 Hz crossover. Would it be worth the extra effort to make a transmission line enclosure over a closed box design? What Hz would I tune the enclosure? Whose transmission line formula is the best?

Curtis,

Can you actually get some FE108Sigmas? They would normally be considered as having too low a Q for a TL, but Martin King has shoen (with his FE208Sigma project) that a mass-loaded TL (ML-TL) can work.

The replacement for the FE108 has a bit higher Q, and some new tricks that should make it a better performing driver.

You also need to consider shielding issues if the L, R are close to the TV monitor and the centre channel is usually even more critical (i avoid the problem by using a virtual centre-channel). There are some Fostex shielded drivers that you might want to consider if this is going to be an issue.

For the $$$ involved in an FE108, you could have 2 FE103s (or FE107s -- i think this is the shielded one) and build a bi-pole (or the 1.5 variation) and not have any issues with baffle-step. The BD-Pipe is an example that i know works well -- even with el cheapo RS 40-1197s (budget FE103s).

The best (available) "formula" for TL design is Martin King's software.

And have a look at my site (URL below), and Bob Brine's site.

dave

[CDJ]

Dave,

Thanks for your info and links. I think I’ll take your advice and purchase the shielded FE107 speakers. Who is a good dealer to get loudspeaker parts?

Thanks again,
The Newbie,
Curtis

[planet10]

Originally posted by CDJ
FE107 speakers. Who is a good dealer to get loudspeaker parts?

For Fostex in the US Madisound.

dave