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
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
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.
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.
Yury,
Go to:
http://www.fostexinternational.com/docs/speaker_comp/ff_enc.shtml
Take a look at the recommended enclosures for the Fostex F200A & FF225K
On the contrary the FE206E will be better in a bigger box
http://www.fostexspeakers.com/fostex.html
Alain.
Go to:
http://www.fostexinternational.com/docs/speaker_comp/ff_enc.shtml
Take a look at the recommended enclosures for the Fostex F200A & FF225K
On the contrary the FE206E will be better in a bigger box
http://www.fostexspeakers.com/fostex.html
Alain.
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?
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?
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
Scott
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
Scott
/sreten.
gday! no, I mean distortion induced flow separation by filtres.
I won't separate voice range. it should be from one sourse.
it's just my opinion, not more.
I have active sub and want to use it as lowrange part of these loudspeaker. let's it add heart, interior for system from 30Hz to 80 Hz. but other sound wave band I want to get from one sourse and plan to use 2 pcs 8" driver for it.
that's why I ask all of you about Fostex.
should it work together I hope it will be better, couse they have to equilibrate individual distortion, system take range of power as overload characteristics and it'll has more linear gain-frequency respons.
sealed box has the best impact characteristics. variovent just like sealed, but allow to make box smaler. that's why I want to use it.
mr elliot agrees with him...
http://sound.westhost.com/biamp-vs-passive.htm#3.0
from what i get, with passive xover networks in the output circuit, you block the electromotive feedback (from the speaker drivers momentum) back into the amp outputs unequally, introducing an unbalanced load on the +/- outputs.
how does that not affect anything?
better amps will have very low output impedance, making this voltage source somewhat significant.
or no?
http://sound.westhost.com/biamp-vs-passive.htm#3.0
from what i get, with passive xover networks in the output circuit, you block the electromotive feedback (from the speaker drivers momentum) back into the amp outputs unequally, introducing an unbalanced load on the +/- outputs.
how does that not affect anything?
better amps will have very low output impedance, making this voltage source somewhat significant.
or no?
I'm not sure I agree with the notion that 'better amps will have a lower output impedence.' Well, yes, in some cases, but not all. What is 'better' depends on the application you intend to use it with.
Active = better as a general rule of course, of course. Very few would deny that. In terms of filtering, active DSP will allow you to compensate for aberations in the driver's frequency response up and down, which a passive filter cannot do effectively, and also keep the driver's efficiency high.
Sorry, but I still don't see how you can possibly hope to achieve this. I've had a go in Martin's MathCad sheets (not that I really needed to to confirm this), and you're trying to achieve the impossible -you can't contravene the laws of physics you know.
You want a box enclosure for the full-range units. Fine, no worries there in itself. But it's the combination of factors you want that's the problem. Let's use the FE206E as an example shall we.
OK, the recommended vented enclosure for this driver is 45L, and it's F3, which, like all vented enclosures, is very steep, is in reality around 75Hz. A sealed enclosure for this driver would need to be much larger for it to get even close to this. A variovent will fall somewhere between the two sizes. Let me re-iterate: a variovent enclosure will need to be LARGER, not smaller, than a vented box using the same driver. Call it 60L (and that's being very optimistic) There's nothing fancy about variovents; it's just aperiodic -a leaky, sealed box in other words. But you want to use a smaller box than the recommended enclosure. You can do it, but it will roll-off much higher -far higher than you want to cross your subs over.
It gets worse. You want to put 2, not 1 drivers into this enclosure, which is already in practical terms too small for just one 8" full-range unit to get down to the level you need. Those drivers will cut off very high indeed, and there will also probably be a massive peak (+10 or so decibels) when they do. And you can't compensate for this, because you refuse to use any filters. I'd expect this cut-off to occur at around 150Hz (at the very lowest), so you're going to get a giant hole in the frequency response between 80Hz, which is the upper limit of the range you want to run your subs, and the lower limit of the full-range drivers in the enclosure you wish to put them in.
OK, next problem. Assuming you've invented a new form of physics which will allow you to stuff those two drivers into an enclosure which is actually too small for just one of them and get them to go low enough to cross over smoothly to your subs, you'll have to go bipolar with these full-range units, unless you roll one of them off (which you can't do because you don't want any filters). If you don't go bipolar, on top of the major issues I've just described, you'll run into severe lobing problems because, even if you mount the full-range units with their surrounds touching each other, the physical size of the 8" driver-cones keeps the centres of the drivers, which produce the higher frequencies, too far apart. The result will be a very ragged response curve above 1KHz, and this will get progressively worse the higher you go.
So, bipolar is your only option in this respect. As it happens, that's usually a good way forward anyway, particularly in your case, because as you refuse to use any filters, if you just mounted the drivers on the front baffle, you'll run into severe baffle-step diffraction issues.
I don't want to seem down, and believe me I'm not intending criticism here (not my way -I like to help and encourage everyone as much as I can, if I can in our hobby), but I honestly believe you might have to have a rethink of your intended approach. It will reap rewards in the long term.
If I might ask some questions? We might be able to come up with some workable solutions, trying to keep your size and other requirements in mind.
1) What sort of music do you listen to?
2) How large is your room and what shape?
3) Where are you intending to put the speakers?
4) How loud do you like to listen?
Regards
Scott
Active = better as a general rule of course, of course. Very few would deny that. In terms of filtering, active DSP will allow you to compensate for aberations in the driver's frequency response up and down, which a passive filter cannot do effectively, and also keep the driver's efficiency high.
Sorry, but I still don't see how you can possibly hope to achieve this. I've had a go in Martin's MathCad sheets (not that I really needed to to confirm this), and you're trying to achieve the impossible -you can't contravene the laws of physics you know.
You want a box enclosure for the full-range units. Fine, no worries there in itself. But it's the combination of factors you want that's the problem. Let's use the FE206E as an example shall we.
OK, the recommended vented enclosure for this driver is 45L, and it's F3, which, like all vented enclosures, is very steep, is in reality around 75Hz. A sealed enclosure for this driver would need to be much larger for it to get even close to this. A variovent will fall somewhere between the two sizes. Let me re-iterate: a variovent enclosure will need to be LARGER, not smaller, than a vented box using the same driver. Call it 60L (and that's being very optimistic) There's nothing fancy about variovents; it's just aperiodic -a leaky, sealed box in other words. But you want to use a smaller box than the recommended enclosure. You can do it, but it will roll-off much higher -far higher than you want to cross your subs over.
It gets worse. You want to put 2, not 1 drivers into this enclosure, which is already in practical terms too small for just one 8" full-range unit to get down to the level you need. Those drivers will cut off very high indeed, and there will also probably be a massive peak (+10 or so decibels) when they do. And you can't compensate for this, because you refuse to use any filters. I'd expect this cut-off to occur at around 150Hz (at the very lowest), so you're going to get a giant hole in the frequency response between 80Hz, which is the upper limit of the range you want to run your subs, and the lower limit of the full-range drivers in the enclosure you wish to put them in.
OK, next problem. Assuming you've invented a new form of physics which will allow you to stuff those two drivers into an enclosure which is actually too small for just one of them and get them to go low enough to cross over smoothly to your subs, you'll have to go bipolar with these full-range units, unless you roll one of them off (which you can't do because you don't want any filters). If you don't go bipolar, on top of the major issues I've just described, you'll run into severe lobing problems because, even if you mount the full-range units with their surrounds touching each other, the physical size of the 8" driver-cones keeps the centres of the drivers, which produce the higher frequencies, too far apart. The result will be a very ragged response curve above 1KHz, and this will get progressively worse the higher you go.
So, bipolar is your only option in this respect. As it happens, that's usually a good way forward anyway, particularly in your case, because as you refuse to use any filters, if you just mounted the drivers on the front baffle, you'll run into severe baffle-step diffraction issues.
I don't want to seem down, and believe me I'm not intending criticism here (not my way -I like to help and encourage everyone as much as I can, if I can in our hobby), but I honestly believe you might have to have a rethink of your intended approach. It will reap rewards in the long term.
If I might ask some questions? We might be able to come up with some workable solutions, trying to keep your size and other requirements in mind.
1) What sort of music do you listen to?
2) How large is your room and what shape?
3) Where are you intending to put the speakers?
4) How loud do you like to listen?
Regards
Scott
Scott,
You have already put a lot more time into this discussion then I have and your points are well stated, I don't have anything else to add.
I have looked at the reference provided above and still do not see how the distortion conclusions have been reached, so I am going to bow out. My take on the reference is a little bit different. I am not following the logic above and must have missed something.
Did you try the newer version of the worksheet I sent, did it run on any of the PC's you tried?
You have already put a lot more time into this discussion then I have and your points are well stated, I don't have anything else to add.
I have looked at the reference provided above and still do not see how the distortion conclusions have been reached, so I am going to bow out. My take on the reference is a little bit different. I am not following the logic above and must have missed something.
Did you try the newer version of the worksheet I sent, did it run on any of the PC's you tried?
Yury, you may want to have a look at this speaker built by Omega. Uses a Visaton B200 driver run fullrange in an aperiodic box with two vents:
http://www.redwineaudio.com/Omega_B200_Aperiodic.html
The drivers are probably available in your area. The B200 has a rising response but most report that once broken in the rise is less obvious. Some are running this driver on open baffles(dipole) because of its qt of ~.7.
Also, the previous posters to this thread know way more than I about designing speakers.
http://www.redwineaudio.com/Omega_B200_Aperiodic.html
The drivers are probably available in your area. The B200 has a rising response but most report that once broken in the rise is less obvious. Some are running this driver on open baffles(dipole) because of its qt of ~.7.
Also, the previous posters to this thread know way more than I about designing speakers.
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