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Artmaster 7th December 2005 02:21 PM

full range without filtres
gday all!
yes, I'm realy want to make floorstanding loudspeaker, using 1 full range driver and without any passive filtres.
that's because anything between amp and driver is sourse of distortion.
now I've to choose driver for it. I have active sub, thus I need driver for sealed box 30-40 litres for 60 Hz-12kHz (enough) with line gain-frequency characteristic. 8"
for example FOSTEXS. FF225K or FE206E

give me advise please.
thank you

Godzilla 7th December 2005 02:43 PM

Fostex 167e or f200a should work great in boxes that size.

Artmaster 7th December 2005 02:48 PM

thank you. 165 is small one. 200 - ok for my opinion.
next issue. what do you think about variovent? it's not sealed exactly, but I like this idea.

Scottmoose 7th December 2005 03:48 PM

The F200a is a wonderful driver, though not the cheapest out there. It'll play louder without distorting than the FF225K however, and should have better detail thanks to that monster alnco magnet. Veriovents -not worth the bother in my view. If you're going for a sealed box of that size, you won't get any genuine benefts from having it.

One question however -why do passive filters introduce distortion? I have not experienced this myself in any of the many TL, OB and horn enclosures I have built, and they can bring worthwhile benefits. That said, I can imagine that a poorly adjusted one will screw up the freqency response, but that's not the fault of the filter per se, but a design error. The one down-side is that they can take a few db off of your sensitivity, so if you're running a very low-power amp, it won't work as well. Some combinations don't need them, some do -but don't rule them out completely.

Alain Dupont 7th December 2005 05:47 PM


Go to:
Take a look at the recommended enclosures for the Fostex F200A & FF225K

On the contrary the FE206E will be better in a bigger box


Artmaster 8th December 2005 07:01 AM

thank you gentlemen!
yes, I'm sure . passive filters realy introduce distortion. freqency and phase. and I'm just want to make system without it.

45 litles - it's so big for me.
to tell the true, I want to combined sub with this full range part.
it's seems like 2 pcs floorstanding loudspeaker included 15" active sub into 40-60 litres bottom side
and the rest place on top inside - Fortex, or something another. I'm not sure yet.
that's why I have room 15-20 liters only. ok, maximum 30, but I have to be sure about necessaries. it's not enough for F200a and I want to use variovent as well.
what do you think about it?

Artmaster 8th December 2005 07:26 AM

one more thing. I'm plan to use 2 pcs 8" fullrange driver per unit.
it's not for big loud, I hate it, no - it's for surge capability

Scottmoose 8th December 2005 09:31 AM

Ouch. if you're wanting a box enclosure you're basically making a set of requirements which are to my way of thinking, fundamentally incompatible here. You want to use 8" drivers (e.g. the Fostex FF225K, FE207E, FE206E or F200a), but go with a smaller than recommended box. That's do-able (kind of), though I don't think a variovent will be the best option here -it just results in a leaky, aperiodic-style enclosure, which would be larger than the recommended vented box[es] on the Fostex site. Lowther's tend to have a smaller VAS than Fostex units if memory serves, so you might want to take a look at their drivers. However, they do cost a whole-lot more! (probably worth it, and that's coming from a massive Fostex-fan like me!)

However, we then run back into the problem of the major aberrations in the frequency response stuffing an over-large driver into a small enclosure is going to cause -I'd expect massive peaking at cut-off, which will be much higher than normal, so you'll need to run your sub part up a fair-old way -circa 150Hz-200Hz as a very rough guess. Not in itself a problem, there's qiute a few sub-drivers that can do that, but just something to remember. As you don't want to use any kind of passive filter to remove the response aberrations, I assume you're going to take care of them with an active filter or DSP, and probably an active crossover as well, which is a good choice, and much more flexible than passive.

Adding a second driver to any box enclosure though will instantly double VAS, and hense the enclosure size, which I believe is what you're hoping to avoid; you'd have to go larger, like it or not with two 8" drivers per side in this case, though if you're using DSP and active filtering, you might be able to flatten the response out without going too far. It's probably going to be well over 45L in volume though. I'd also advise with 2 drivers per side running them in a bipolar configuration, or use your active filters / crossover to roll one of them off quite quickly, or you'll run into the problems familiar to the line-array brigade -lobing issues, polar response problems etc. (that's why there aren't many line-arrays out there using full-range drivers, and even less using full-rangers that are any good).

A good option might be to go open-baffle with these drivers, rather than a box-enclosure of any kind. As you're intending to use active correction(?) anyway, then this should solve many of these difficulties at a stroke, and most people who go dipolar never look back.

Good luck & all the best

MJK 8th December 2005 10:51 AM


using 1 full range driver and without any passive filtres. that's because anything between amp and driver is sourse of distortion.
What causes the distortion, where does it come from? The passive components themselves cause distortion? How and why? What does the distortion sound like?

soongsc 8th December 2005 11:03 AM

In reality, the driver causes significantly more distortion than other componenets, and is still the main souce of distortion in the whole audio chain.

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