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Discussion Starter · #1 ·
Has anyone used the KEF Ci200RR ?


I'm thinking of using them in front-ported inwall application for a 5.0 and would appreciate feedback.


Thanks.
 

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They're brand new. The drive units look like a variant of the KEF Q900's driver, perhaps even the same part number. That's a good sign, as that concentric is IMO the best 8" one currently on the market at any price.
 

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Discussion Starter · #3 ·
Yes, I've heard the lineage is the Q900.


KEF seems to refer to it as in-ceiling, but I'm interested in putting it in a front ported box.


Does anyone know of FR graphs for the Q900 UniQ driver?
 

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Quote:
Originally Posted by rick240  /t/1523856/kef-ci200rr-has-anybody-used-them/0_100#post_24521534


Yes, I've heard the lineage is the Q900.


KEF seems to refer to it as in-ceiling, but I'm interested in putting it in a front ported box.

Don't do that. You want to keep excursion down to an absolute minimum. That means using them in closed boxes with either a high cross or with supplemental woofers.
Quote:
Originally Posted by rick240  /t/1523856/kef-ci200rr-has-anybody-used-them/0_100#post_24521534


Does anyone know of FR graphs for the Q900 UniQ driver?

Here are the ones in my nearfield speakers:


Woofer:



Tweeter:
 

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Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them/0_50#post_24525230


Don't do that. You want to keep excursion down to an absolute minimum. That means using them in closed boxes with either a high cross or with supplemental woofers.

? A ported box XO'd to a sub will have much lower excursion and more bass output than a sealed one.
 

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IMO, ported mains are always a bad idea. They're just hard to integrate cleanly with subs, because they switch so abruptly from monopoles to dipoles.


Also, remember that right above tuning a 4th order box has higher excursion than a 2d order box.
 

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Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them#post_24529967


IMO, ported mains are always a bad idea. They're just hard to integrate cleanly with subs, because they switch so abruptly from monopoles to dipoles.


Also, remember that right above tuning a 4th order box has higher excursion than a 2d order box.

Can you elaborate a little more on this? What do you mean by switching so quickly from monopole to dipole? Are you saying that the ports if located in the rear would cause a dipole like effect, or the way the low frequencies radiate Omni-directionally?


I have always been a fan of ported LCR's as it seems to have a more full sound to the lower mid-range area, especially on male vocals, but, I realize that sealed mains would likely sound similar if not somewhat the same with an 80hz crossover. Well. Not 100% sure on that. I do, of course, realize that anything below 80hz will not be localized but rather omni-directional as I said above. So perhaps what I am hearing is something other than the lower end output advantage with ported versus sealed.


Also, what do you mean by 4th order box, and 2nd order box? I know that a 4th order crossover will be down 4 octaves at the crossover point, and a 2nd order down 2 octaves. Can you clarify that as well?
 

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Quote:
Originally Posted by Martycool007  /t/1523856/kef-ci200rr-has-anybody-used-them/0_100#post_24530225


Can you elaborate a little more on this? What do you mean by switching so quickly from monopole to dipole? Are you saying that the ports if located in the rear would cause a dipole like effect, or the way the low frequencies radiate Omni-directionally?

I'm meant exactly what I wrote: above vent tuning a vented speaker is a monopole, and below vent tuning a vented speaker is effectively dipole. It doesn't matter where the port is located.
Quote:
Originally Posted by Martycool007  /t/1523856/kef-ci200rr-has-anybody-used-them/0_100#post_24530225


I have always been a fan of ported LCR's as it seems to have a more full sound to the lower mid-range area, especially on male vocals,

The phrase for that is "port resonance colorations."
Quote:
Originally Posted by Martycool007  /t/1523856/kef-ci200rr-has-anybody-used-them/0_100#post_24530225


Also, what do you mean by 4th order box, and 2nd order box? I know that a 4th order crossover will be down 4 octaves at the crossover point, and a 2nd order down 2 octaves. Can you clarify that as well?

4th order = 24dB/oct rolloff below cutoff = dipole.

2d order = 12dB/oct rolloff below Fb = monopole.
 

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Discussion Starter · #9 ·

Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them#post_24525230


Don't do that. You want to keep excursion down to an absolute minimum. That means using them in closed boxes with either a high cross or with supplemental woofers.

No room for supplemental woofers - it would be just the Ci200RR.


How big a sealed box would be need for an F3 in the 60 - 80Hz range?


That woofer looks like it starts to go a bit crazy under 200Hz; or can all of that be smoothed reasonably with a good xo? Any trouble pushing it to a 80Hz crossover in a sealed box?
 

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Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them/0_50#post_24529967


IMO, ported mains are always a bad idea. They're just hard to integrate cleanly with subs, because they switch so abruptly from monopoles to dipoles.

Not if Fb is a half octave or more below XO, and with the XO in place the phase difference between closed and vented is minimal.


Vented becomes a dipole? That's a new one on me.


If you mean because the port and cone are out of phase, I don't think that counts, because the cone is hardly moving and output is dominated by the port, and it certainly doesn't exhibit a figure-8 dipole radiation patern.
Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them/0_50#post_24529967


Also, remember that right above tuning a 4th order box has higher excursion than a 2d order box.

Not sure what you mean here either, I don't see that in WinISD.


And even if true, it's not really, because if normalized for the same output the vented excursion would be much less.
 

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Quote:
Originally Posted by rick240  /t/1523856/kef-ci200rr-has-anybody-used-them/0_100#post_24530514

Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them#post_24525230


Don't do that. You want to keep excursion down to an absolute minimum. That means using them in closed boxes with either a high cross or with supplemental woofers.

No room for supplemental woofers - it would be just the Ci200RR.


How big a sealed box would be need for an F3 in the 60 - 80Hz range?

You don't want a sealed box in the 60-80Hz range. You want a highpass and 100-150Hz to the subs. Or you want a different drive-unit.


That said, mine are sealed, and maybe half a cube, with an F3 in the 70s. I would not recommend that alignment for anything but nearfield use, but for nearfield use excursion is low enough that it works fine with just a second-order highpass on the mains and a 4th order highpass on a sub that's flat and extended well beyond an octave above Fc.
Quote:
Originally Posted by rick240  /t/1523856/kef-ci200rr-has-anybody-used-them/0_100#post_24530514


[That woofer looks like it starts to go a bit crazy under 200Hz; or can all of that be smoothed reasonably with a good xo? Any trouble pushing it to a 80Hz crossover in a sealed box?

Those measurements aren't valid down low, just from 300Hz or so (I think, don't remember the gating) up. And forget a crossover that low. You want to limit excursion on the midrange cone.
Quote:
Originally Posted by noah katz  /t/1523856/kef-ci200rr-has-anybody-used-them/0_100#post_24530678


Not if Fb is a half octave or more below XO, and with the XO in place the phase difference between closed and vented is minimal.

My experience is that vented mains tuned in the modal region (i.e. above 40Hz or so) are as a practical matter not easy to integrate coherently with subs. So I would never do non-sealed mains.
Quote:
Originally Posted by noah katz  /t/1523856/kef-ci200rr-has-anybody-used-them/0_100#post_24530678


Vented becomes a dipole? That's a new one on me.

The backwave cancels the front. Textbook definition of "dipole."


And an OB clearly isn't a figure 8 in the modal region, either.
Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them/0_50#post_24529967


Also, remember that right above tuning a 4th order box has higher excursion than a 2d order box.

Not sure what you mean here either, I don't see that in WinISD.


And even if true, it's not really, because if normalized for the same output the vented excursion would be much less.[/quote]


I don't use winisd, so I can't vouch for its accuracy.
 

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Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them/0_50#post_24534011


My experience is that vented mains tuned in the modal region (i.e. above 40Hz or so) are as a practical matter not easy to integrate coherently with subs. So I would never do non-sealed mains.

What happens at Fb doesn't matter if it's not in the passband.
Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them/0_50#post_24534011


MThe backwave cancels the front.

That's if the dipole has equal output front and rear, which is not the case for the port and driver.
Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them/0_50#post_24534011


MI don't use winisd, so I can't vouch for its accuracy.

Try it with whatever you use.
 

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Discussion Starter · #13 ·

Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them#post_24534011


You don't want a sealed box in the 60-80Hz range. You want a highpass and 100-150Hz to the subs. Or you want a different drive-unit.

I want a 80Hz crossover, otherwise there will be issues with being able to locate the subwoofer.


So that means a sealed unit with these drives isn't feasible - I buy that.


I'm still having difficulty understanding the issue with using a port.


Are you arguing against using ports in speakers, period?


Also, unless I am reading wrong, your issue seems to be with rear ports - and I have always been proposing front ports.


Would this drive in a front ported box provide a decent HT speaker when crossed at 80Hz?
 

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Quote:
Originally Posted by rick240  /t/1523856/kef-ci200rr-has-anybody-used-them/0_100#post_24535939

Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them#post_24534011


You don't want a sealed box in the 60-80Hz range. You want a highpass and 100-150Hz to the subs. Or you want a different drive-unit.

I want a 80Hz crossover, otherwise there will be issues with being able to locate the subwoofer.

Nonsense.
Quote:
Originally Posted by rick240  /t/1523856/kef-ci200rr-has-anybody-used-them/0_100#post_24535939


I'm still having difficulty understanding the issue with using a port.

Are you arguing against using ports in speakers, period?

Yes, I am generally saying to avoid 4th order systems (vented or PR) for mains. At least when the speakers are used (either crossed over to or augmented by) with subwoofers. If the mains are used without bass augmentation, then a higher order bass system makes sense to eke out more usable bandwidth.


I don't know where you got the idea that the direction of the port matters. I certainly never wrote anything to that effect. Vents or passive radiators are a bad idea for mains in a system with subwoofers, no matter which way the resonant device faces.
 

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You said


"IMO, ported mains are always a bad idea. They're just hard to integrate cleanly with subs, because they switch so abruptly from monopoles to dipoles."


I responded


"Not if Fb is a half octave or more below XO, and with the XO in place the phase difference between closed and vented is minimal."


If you disagree, why?


You may say then why bother if you're not even going to get the benefit of the output at Fb; the answer is to get a very usable amount of bass from a low Q woofer down to XO with only slightly more phase shift than sealed.
 

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Discussion Starter · #17 ·

Quote:
Originally Posted by noah katz  /t/1523856/kef-ci200rr-has-anybody-used-them#post_24539572


You may say then why bother if you're not even going to get the benefit of the output at Fb; the answer is to get a very usable amount of bass from a low Q woofer down to XO with only slightly more phase shift than sealed.

And in the case of this discussion, if a sealed design would need a XO of 100 - 150Hz could a ported design get that XO down to the desired 80Hz without have dipole issues?
Quote:
Originally Posted by DS-21  /t/1523856/kef-ci200rr-has-anybody-used-them#post_24538270


I don't know where you got the idea that the direction of the port matters. I certainly never wrote anything to that effect.

Sorry, I misread your earlier post
 

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Quote:
Originally Posted by Face2  /t/1523856/kef-ci200rr-has-anybody-used-them/0_100#post_24548747

Quote:
Originally Posted by noah katz  /t/1523856/kef-ci200rr-has-anybody-used-them#post_24548504


There's no such thing as dipole issues with regard to ports.
+1...I've never seen such measurements.

You've never seen a dipole (4th order) rolloff below cutoff in a vented box, with the driver widely flapping due to it having transitioned from monopole loading to dipole loading?
 
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