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If Crossover at 400Hz, what LF cabinet is preferred: Jubilee or Khorn?


jwc

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I'm opening a can of worms here.

 

Leave subwoofer out of this discussion.

 

It appears to me that the majority of the Jubilee owners here are XO their Jubes at 400Hz.  Why would you pick one LF over the other if you were to put the current K402 horn/B&C691 driver on top?  Regardless whether active or passive.  Assume Khorn had a Back built onto it like some have done on their own or like the modern production Khorn has.

 

jc

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Funny Roy talked about this at the pilgrimage demo of the Jubs. He stated it’s not the electrical parameters active or passive that define the acoustical crossover point which in the case of the Jub/K402/K691 is at 500Hz acoustically and has always been in both his active and passive setups for the Jubilee with K402.

 

In other words the electrical parameters are chosen for the goal of 500Hz acoustical crossover point.

 

Jubilee LF has a more consistent expansion and lower distortion over most of the frequency region that the Jubilee and KHorn are typically being used. The Jubilee with the PEQ at 32Hz also gives a noticeable improvement in that region over the KHorn. 

 

miketn

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1 minute ago, mikebse2a3 said:

PEQ at 32Hz also gives a noticeable improvement in that region over the KHorn. 

And why not do that with the Khorn?

 

Also, is there a a documented comparison.....chart for chart of the lower distortion?

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So Jube system with LinkW 24 Crossover High Pass 400Hz and LinkW 24 Crossover Low Pass 450Hz, the acoustical XO is 500Hz?

 

So what would be the Acoustical XO with a Khorn using an active......start with putting it in the chamber......and go from there...?

 

image.thumb.png.2e3c077bc86edef3591830710f161f72.png

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On 5/30/2018 at 10:47 AM, jwc said:

And why not do that with the Khorn?

 

Also, is there a a documented comparison.....chart for chart of the lower distortion?

 

In the original Jubilee article (JAES), the 2 and 3rd harmonic distortion is plotted. Over most of the band, the Jubilee has about 1/3 the distortion of a K-Horn.

Regarding the PEQ at 32Hz, this is tricky since you do not want to tear up the woofer. Roy, has given his blessing that the K-31 woofer will not suffer with the PEQ. I don't know if the K-33 in the K-Horn could handle that PEQ. Best to ask Roy on that question. 

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58 minutes ago, jwc said:

I'm opening a can of works here.

And your reasoning for doing so is...?

 

58 minutes ago, jwc said:

It appears to me that the majority of the Jubilee owners here are XO their Jubes at 400Hz.

Mine have always turned out to be more like 425-450 Hz because the compression driver doesn't sound very good below that point.  The K-402-MEH acoustically crosses a little above 500 Hz.

 

58 minutes ago, jwc said:

Why would you pick one LF over the other if you were to put the current K402 horn/B&C691 driver on top? 

I listen to the compression driver, and then I look at the bass bass frequency response and coverage angles.  I try to join those two at the best tradeoff point that I can. The on-axis FR of the Khorn bass above 400 Hz doesn't do so well and the polars are even worse (not plotted):

 

756682849_KhornbassbinFR.thumb.JPG.b62d526b671130959509974dc9f99a0c.JPG

 

11 minutes ago, jwc said:

I'm at work....can somebody repost that page that shows the distortion curves.

1958091086_JubandKhornbassbinndharmonicdistortion.thumb.JPG.bcc9764afa9d5805e365634ffebcbc84.JPG

596462652_JubandKhornbassbin3rdharmonicdistortion.thumb.JPG.0da5fd1da11108433933e1f95c522162.JPG

 

Chris

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I remember now.  Don't know about 1/3 though.  Its been so long since I looked at the article and knew it cold over 10 Years ago.

 

What is up with the Jube distortion starting before 300Hz?

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I also find that the lower-order harmonics don't really tell the story that the ears do listening to the bass bins,  I'd recommend looking at the higher order harmonics instead (I've presently only got the Jubilee bass bin HD plots handy but it is indicative of what you'd see from the Khorn bass bin):

 

96447162_JubileeBassBInatOneMetreOn-AxisHarmDist.thumb.jpg.e9111bf6d5954189ce1bfb8bbb0e5adc.jpg

 

Note: the above measurement was done at 100 dB on-axis at one metre, EQed flat.

 

Chris

 

 

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53 minutes ago, jwc said:

I remember now.  Don't know about 1/3 though.  Its been so long since I looked at the article and knew it cold over 10 Years ago.

 

What is up with the Jube distortion starting before 300Hz?

 

If you look at the distortion as a percentage, the Jubilee (final prototype) is about 1/3

The scale you are looking at is in dB not percentage.

 

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1 hour ago, jwc said:

I'm opening a can of works here.

 

Leave subwoofer out of this discussion.

 

It appears to me that the majority of the Jubilee owners here are XO their Jubes at 400Hz.  Why would you pick one LF over the other if you were to put the current K402 horn/B&C691 driver on top?  Regardless whether active or passive.  Assume Khorn had a Back built onto it like some have done on their own or like the modern production Khorn has.

 

jc

 

Some listening is in order, but the crossover point should be comfortably inside the frequency limits of each horn.  Each horn contributes significantly to the sound for at least an octave beyond the crossover point, so you'd want that point to be well within the capability of each.  Polar responses also contribute to the crossover point selection.  I asked and got a non-answer when the K-horn AK-4 or 5 came out and the tweeter crossover was lowered to 4500 Hz.  My first reaction was that is was more for matching polar response than the weakness in HF from the K-55-X .  Classically, the low pass for a horn should be at least an octave above cut-off.  However, the K-400's actual cut-off is about 273 Hz and it is used at about 400 in a K-horn and La Scala.  About because first order crossovers are fairly imprecise.  Mr. Paul didn't always follow the "rules", exactly. 

 

The Jubilee was designed to address the lack of HF output of the K-horn, so the crossover point could be 500 Hz or higher, enabling a 2-way system.  If youu like a 600 Hz crossover, use it.  It will reduce diaphragm travel in the K-691 and that should buy you less distortion.  As I remember, the Jubilee can reach 1k Hz and a little more. 

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As I recall, the Jubilee may have been first designed to reach about 800 Hz.

Crossing that high, does put you in the territory where the polars are starting to "clover leaf" due to the bifurcated mouth. There are certainly a number of factors involved in choosing a proper crossover point.

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Yes, here is the problem (the dark line in the plot below).  The Jub (and Khorn, which is worse) bass bin polars beam above about 220 Hz due to the separated (bifurcated) mouths.  You can hear that in the mid-bass and lower midrange (relative to the K-402-MEH configuration which has full polar coverage of 60 by 90 degrees at those frequencies):

 

KPT-KHJ-LF (Jub Bass Bin) Directivity plot.jpg

 

One way to deal with that is to put a nose and extended side panels on the bass bin:

f6e40fbabe60ce6bb2908d4bb8456995.jpg

 

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5 hours ago, jwc said:

I'm opening a can of works here.

 

Leave subwoofer out of this discussion.

 

It appears to me that the majority of the Jubilee owners here are XO their Jubes at 400Hz.  Why would you pick one LF over the other if you were to put the current K402 horn/B&C691 driver on top?  Regardless whether active or passive.  Assume Khorn had a Back built onto it like some have done on their own or like the modern production Khorn has.

 

jc

 

Your speakers eat Khorns for breakfast and Jubs for lunch.   

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MWM bass bins have the same issue of polar narrowing due to truncated bifurcated mouths (unlike the La Scala bass bin).  If you haul your bass bins outside and do polar measurements, you'll see the "cloverleafing" vs. frequency that was mentioned above.  Here's a horizontal coverage polar plot for a "KPT-MCM-II" from Klipsch's EASE data that shows that coverage narrowing vs. frequency above 160 Hz to 250 Hz which is where the midbass module begins to kick in (a K-402 horn in a KPT-305 module, I believe)

 

KPT-MCM-Angled-2-THX-new.jpg

 

1236552429_KPT-MCM-IIhorpolarplot.thumb.JPG.c8dce15a13586b4319c146e27f8b271b.JPG

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