It was crossed at 900Hz, and the simulations based on flat baffle measurements looked very good. However, once in the XKi, there was a lot of bass and midbass gain and the output was of order 100dB from 100Hz to 300Hz that it over powered the 94dB tweeter. I am trying to figure out a workaround but at present the balance is not right. My mock up with a single Beta 8cx driver XKi and the tweeter sounded very good. Something about the two drivers in one cabinet that is overly synergistic. It might be that 3/4in Baltic birch is very stiff and the sensitivity is higher than a flexible foam core box that was the mock up. May try changing the dome tweeter for 5MR450NDY and crossed maybe 350Hz.
Yes, the setback was for time alignment. The Beta 8cx has a plugged coax (inactive).
Yes, the setback was for time alignment. The Beta 8cx has a plugged coax (inactive).
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although probably of little if any help for this situation, an extended K-tube can be used to "pipe" highs and reduce interaction with a K front chamber. Carl did it with dome tweeters on car coax in little "Rocket" klams - the video below is my klam 15 with its coax horn temporarily extended with a pipe and a 5.3" long K-tube. This klam plays nice (lucked out) without the K-tube but that would remove some of the "reverb" tone. I really like using K-tubes.
YouTube
YouTube
hey guys - - I'd like a K - perhaps XKi to compare to K12 or K15 - any suggestions? - can be coaxial or woofer + K-tube - wood cabinet.
also - am still curious about the 8in. XKi Beta8cx and FE206EN for multichannel
also - am still curious about the 8in. XKi Beta8cx and FE206EN for multichannel
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when working with a midrange centered K, it might be worth trying the R-J style instead as the front chamber is quite small - just he cone's volume and volume between the front baffle and the spaced speaker baffle
JBL's slot could be used
JBL's slot could be used
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Hi xrk971,
I have read every page of this thread. I am planning on making my own pair of these.
However, which of the two pairs of drivers would you recommend to build for a pair of computer desktop speakers?
The RS100-4s (aluminum or paper), or the PA130-8s?
You first built with the RSs, but then later built with the PAs. To my eyes it looks like the RSs have a smoother response but the PAs are a more "fun" speaker, is that correct?
Where I am the RSs are slightly more expensive than the PAs (RS aluminum are $55AUD ea, the RS paper are $60AUD ea, and the PAs are $48AUD each).
Thanks heaps for your time and valuable knowledge!
I have read every page of this thread. I am planning on making my own pair of these.
However, which of the two pairs of drivers would you recommend to build for a pair of computer desktop speakers?
The RS100-4s (aluminum or paper), or the PA130-8s?
You first built with the RSs, but then later built with the PAs. To my eyes it looks like the RSs have a smoother response but the PAs are a more "fun" speaker, is that correct?
Where I am the RSs are slightly more expensive than the PAs (RS aluminum are $55AUD ea, the RS paper are $60AUD ea, and the PAs are $48AUD each).
Thanks heaps for your time and valuable knowledge!
I would go with PA130-8’s. But it has limitations of high end vs RS100’s. RS100’s are going to have more high frequency but they are much smaller and less efficient so won’t have as deepnof bass and not play as loud without distorting. You can add a small dome tweeter with say 2.2uF high pass cap as a super tweeter. Mount that at the top of the cabinet or above the K aperture cusp (cyclops style). But the RS100 are a much more compact cabinet so depends on your space on the desktop as well.
If you go with the RS100, I would opt for the aluminum. I built the XKi with the RS100p and it just doesn't have enough top end. Very impressive, otherwise.
Hey X,
How about these new coax from TB, the W6-2313 and W8-2314?
Driver - TB SPEAKER CO., LTD.
I'm about to order a pair of them, not sure which yet.
Would they work better in the XKi, or in a "maxi"-karlsonator?
Would be a shame to hide that gorgeous driver behind the k aperture, but I have a good feeling about them ...
Wadda you think? 😉
How about these new coax from TB, the W6-2313 and W8-2314?
Driver - TB SPEAKER CO., LTD.
I'm about to order a pair of them, not sure which yet.
Would they work better in the XKi, or in a "maxi"-karlsonator?
Would be a shame to hide that gorgeous driver behind the k aperture, but I have a good feeling about them ...
Wadda you think? 😉
The W6-2313 looks like an ideal XKi driver. The box would be very compact (10L). I noticed they show a finished product shot that looks an awful lot like a KEF LS50. It would work very well, but will need custom XO work and is, I fear, too beautiful (and expensive) to hide behind a K aperture.
if one's worried about hiding a driver :
this K12 set (sans final metal corner and edge trim below) got very high marks by its builder for sound quality and transient response - including the midrange whose back was open - sounding better than it did in a reflex
this K12 set (sans final metal corner and edge trim below) got very high marks by its builder for sound quality and transient response - including the midrange whose back was open - sounding better than it did in a reflex
An externally hosted image should be here but it was not working when we last tested it.
Thanks xrk and ray.
I think I'll go with the PA, and enhance the top end if I find it lacking.
With adding a tweeter, does it need to be 8 ohms? And is there an efficiency target I should look for when choosing one? There are some delicious AMT tweeters that Dayton produce - would one of those be ok or would you only recommend silk dome tweeters?
I think I'll go with the PA, and enhance the top end if I find it lacking.
With adding a tweeter, does it need to be 8 ohms? And is there an efficiency target I should look for when choosing one? There are some delicious AMT tweeters that Dayton produce - would one of those be ok or would you only recommend silk dome tweeters?
I'm thinking specifically this AMT tweeter - AMT Mini-8 Air Motion Transformer Tweeter 8 Ohm - Dayton Audio
It's 88db 1W/m, which is a perfect match to the PA130.
It's 88db 1W/m, which is a perfect match to the PA130.
The Dayton AMT is great. I have tried those and they work well. Since it is well matched in SPL no need to pad with resistor just use bypass cap to taste.
Plexiglass, eh?
That's an idea. Thanks.
I'm looking to see if the W6 will fit well in a MLTL.
If not, I'll get back to this.
Sorry to bug you again xrk, but I have a question about the k-aperature in this design.
Looking at the frequency response for the PA you posted on page 33 (XKi - X's ab initio Karlson 6th Order Bandpass)
There are 3 measurements - 1 against wall (with k), 1 on stand (with k), and 1 without k.
With the one without the k-aperature, was that measured 6-inches from the wall or was that on a stand as well?
The reason I ask is because the k-aperature appears to introduce big dips at 460hz and from 600Hz-1.8kHz. However with the 6 inch from wall measurement you have significantly more bass - is it the k-aperature that is assisting with the bass there, or was it due to being placed closer to the wall?
If the k-aperature is helping with the bass then for me it's a no-brainer to put the k-aperature on there. However if it is only due to being placed close to the rear wall then forgoing the k-aperature (and therefore the dips in the response that it introduces) and making it a 2 way with a smooth tweeter crossed around 3.5kHz-4kHz such as the Dayton TD20F may be a good option, no?
Looking at the frequency response for the PA you posted on page 33 (XKi - X's ab initio Karlson 6th Order Bandpass)
There are 3 measurements - 1 against wall (with k), 1 on stand (with k), and 1 without k.
With the one without the k-aperature, was that measured 6-inches from the wall or was that on a stand as well?
The reason I ask is because the k-aperature appears to introduce big dips at 460hz and from 600Hz-1.8kHz. However with the 6 inch from wall measurement you have significantly more bass - is it the k-aperature that is assisting with the bass there, or was it due to being placed closer to the wall?
If the k-aperature is helping with the bass then for me it's a no-brainer to put the k-aperature on there. However if it is only due to being placed close to the rear wall then forgoing the k-aperature (and therefore the dips in the response that it introduces) and making it a 2 way with a smooth tweeter crossed around 3.5kHz-4kHz such as the Dayton TD20F may be a good option, no?
The K aperture does indeed introduce dips, but they are not bad sounding - vs peaks which are very audible. The K aperture does not increase bass extension much, but what it gives is a wide dispersion acoustic lens and it loads the front cone a bit for more power handling with less cone movement. But that won't be noticeable unless you are pushing the output very loud. If you leave off the K, it becomes a slot vented reflex box. Might as well make a flat front baffle to prevent edge diffraction/reflections.
Aha, well since I'm aiming to build near field desktop computer speakers that I don't need to go really loud with, then perhaps having a flat front baffle and no k will be ideal, if I am crossing to a pair of tweeters.
If making it into just a plain slot vented reflex box, all I need to do is straighten the front baffle but leave the slot dimensions the same, yeah?
Also, sorry for more questions, but if constructing these cabinets from birch ply, will 6mm thickness be enough without needing much bracing, or should I go to 9mm thick?
If making it into just a plain slot vented reflex box, all I need to do is straighten the front baffle but leave the slot dimensions the same, yeah?
Also, sorry for more questions, but if constructing these cabinets from birch ply, will 6mm thickness be enough without needing much bracing, or should I go to 9mm thick?
9mm or 12mm even if you are not going to brace. If bracing, even thin foam core works as you can see. 6mm is pretty thin wood. Vent dimensions keep the same.