fostex fe83en//ff85wk questions

[soundnovice]

what is the freq.range, within which fostex fe83en or ff85wk excel? i need to know the crossover points for these drivers on both the ends.
are these both drivers good as tweeters? or tweeter/super tweeters are required to cover the highs say upto 20khz?

[planet10]

FF85wk reaches up to something like 25k, it makes a really decent tweeter. Not so much the FE83.

At the low end, at limited volume you can squeeze 85-90 Hz out of the FF85wk. The FE83 has almost an octave less reach. These differences are reflected in the efficiency.

At fiyFEST the FF85wk did well with a 1st order at 160 Hz. To plump up the midbass (and allow for an attempt at a passive XO) i'm gonna try 240 Hz next

dave

[Scottmoose]

-Depends what you mean by 'excel'

-That depends on what slopes you're planning on using, what other drivers you are planning on using, the baffle dimensions and shape, and your requirements for the resulting end system. It's not quite as simple as just picking X frequency & using that for whatever order slope you want, since the changing impedance of the driver becomes, or may become, a significant factor, particularly with low order slopes.

-Yes, they've both got useful output to 20KHz on-axis and measure well, especially the 85, which is good for > 20KHz.

-Depends on what your requirements are in terms of HF dispersion. Both are good as wideband units go, but if you need considerable off-axis capability, they're not going to match a quality 3/4in dome or similar.

[planet10]

Originally Posted by planet10

At diyFEST the FF85wk did well with a 1st order at 160 Hz.

Scott's post reminded me that i didn't post the reference picture:



dave

[planet10]

Originally Posted by Scottmoose

Both are good as wideband units go, but if you need considerable off-axis capability, they're not going to match a quality 3/4in dome or similar.

With the 3/4" dustcaps on these they aren't as far behind the tweeter as you may think.

BTW: how is Colin doing on yours?

dave

[Scottmoose]

Good point.

If he's had chance to unpack them yet I'd be surprised since he's back in full time work for a while, & been busy on weekends finishing some orders off, but I've been surprised before.

[fakeout]

I thought the fe83en was for a back loaded horn.

[Scottmoose]

What makes you think that?

[GM]

Originally Posted by fakeout

I thought the fe83en was for a back loaded horn.

Hmm, based on published specs it's not suitable for a BLH except of the Voigt pipe variety such as the BIB.

GM

[Scottmoose]

And it's not going to be a long one of those either...

TBH, based on the published data, I'm honestly struggling to understand what they were trying to do. It'll make a good mid-tweet, but that's about it. Maybe 2 litres, sealed, for desktop monitor use?