Jubilee Crossover Frequency

[Edgar]

Greetings!

I have been interested in building a dual-12" horn bass enclosure since the Klipsch/Delgado article in JAES several years ago. I just discovered these forums the other day, so I've spent the past couple of days catching-up on everyone's posts about building a Jubilee clone.

I have a question about the upper frequency limit of the bass cabinet. People report Jubilee crossovers of 600, 800, even 1000 Hz. But according to the Thiele/Small parameters I've been able to find for various Klipsch 12" drivers, along with Don Keele's horn parameter equations, the woofers themselves run into mass-rolloff well below that:

K-1242 384 Hz

K-22-E 189 Hz

K-22-K 170 Hz

K-23-K 195 Hz

K-24-K 149 Hz

K-25-K 221 Hz

Does Klipsch EQ the Jubilee woofers to extend the HF response?

Thanks,

Edgar

[Colin]

Welcome! Nice avatar too.

Is anybody marrying the Jubilee top horns with a Khorn bass bin?

If so, what are they using for crossovers?

[Duke Spinner]

in a true Horn Loaded enclosure, NOT like an Altec A-7, which is a hornloaded direct radiator ...

i think 300 Hz ...

is pushin' it ..........

[Edgar]

Welcome! Nice avatar too.

Thanks. That's actually a Speakerlab K that I brought into TurboCAD. I bought the plans way back in 1979, but never got around to building it.

Edgar

[sunnysal]

Delgado said in his post on the subject that he crossed at 800hz. I am sure he used an electronic crossover and EQ. I will try to find the post and reference it. check the post in mods where they reference some older posts on the subject. tony

p.s. here is the text of Mr. Delgado´s post I referenced:

"let me clear up so things so that the guessing can stop.

both jubilee lf bass bins were acoustically the same. they just have different wrappers.

the hf drivers on both horns were K-1132 drivers.

the large hf horn is called a k-402. the combo of the 402 horn and 1132 driver is called a Kpt-402-hf.

the small hf horn is called a k-510. we do not have a combo of the 510 and 1132 driver so I can't give you a theater model number.

the acoustic crossover of both systems were identically set at around 800 Hz.

the slopes were 24 db/oct LR filters.

Digital delay was used on both systems, mandatory in my opinion.

very little eq was used on the lf bins. the hf horns require the typical amount of constant directivity compensation to bring it back to a flat power response which in this case corresponds to a flat frequency response.

I did this demo to demonstrate to all the want-to-be-jubilee-owners that an alternative exists and, in my opinion, offers a better sound quality experience by adding additional components. You would need some sort of processor, digital preferred, that gives you the features of 24 db octave filters, some peq adjustments and filter shelving and most importantly, delay. Then of course you would need 4 channels of amplification for stereo. So to recap,

2 kpt-khj-lf
2 kpt-402-hf
or
2 k-510 horns and 2-k-1132 drivers
1 2in/4out (minimum) processor (digital if possible)
2 stereo amps.

If anyone ever ventures to do this, I can supply you with the info to get you closer to experiencing a jub system, that in my opinion, is the best way to experience one...

roy delgado ", so no LF EQ and 800hz as mentioned...

from this thread:

http://forums.klipsch.com/forums/5/636033/ShowThread.aspx

regards, tony

[kaiser SET say]

See this thread from our visit to Hope last weekend! Roy put a passive in to one with a 402 top and crossed it over at 600!

http://forums.klipsch.com/forums/thread/750235.aspx

[D-MAN]

Couple of things: first there are 2-12" drivers in the Jubilee, so the efficiency is doubled automatically. This raises the upper frequency corner based on the decibel rating, of course.

second, the Keele mass rolloff equation in question puts the K33E at 177 Hz, yet it crosses over effectively in the Khorn at approx. 400Hz. I have always found this confusing, but the K33E is not operated at full efficiency in the Khorn, either. Increasing the reactance applied to the driver (in this particular case) widens the bandwidth.

Third, the Jubilee has folds that are optimized to pass higher frequencies than is the Khorn.

The USABLE high frequency corner is much higher than the simple math result would indicate.

DM

[kaiser SET say]

Roy started this thred recently and you may be able to pm him for the answers your looking for[]

http://forums.klipsch.com/forums/thread/749436.aspx

[Guest " "]

Greetings!

I have been interested in building a dual-12" horn bass enclosure since the Klipsch/Delgado article in JAES several years ago. I just discovered these forums the other day, so I've spent the past couple of days catching-up on everyone's posts about building a Jubilee clone.

I have a question about the upper frequency limit of the bass cabinet. People report Jubilee crossovers of 600, 800, even 1000 Hz. But according to the Thiele/Small parameters I've been able to find for various Klipsch 12" drivers, along with Don Keele's horn parameter equations, the woofers themselves run into mass-rolloff well below that:

K-1242 384 Hz

K-22-E 189 Hz

K-22-K 170 Hz

K-23-K 195 Hz

K-24-K 149 Hz

K-25-K 221 Hz

Does Klipsch EQ the Jubilee woofers to extend the HF response?

Thanks,

Edgar

Very intresting. Those numbers are at least one octave lower than I would have expected.

[sunnysal]

p.p.s. more from Mr. Deglgado about WHY 800hz:

"Hi Tony,

Yes we make the driver here in Hope. As to crossover point, I use several pieces of data for determining crossover point:

1. First the amplitude of both the lf and hf must be smooth at crossover and hopefully provide plenty of overlap. by that i mean, you want the lf rolloff on the top end to be well above the low end rolloff of the hf. i call this the crossover overlap band.

2. phase value of the hf and lf should be stable and close to each in other in value in the crossover overlap band.

3. coverage angle values of the hf and lf should be stable and close to each in value in the crossover overlap band.

In the case of the jub lf and 402/510 horn, the overlap region is from about 500 Hz to about 900 Hz. Below 500 Hz, the 402 and 510 horns, begin to rolloff, phase values are changing rapidly and the coverage angle values are high. Above 900, the lf is beginning to show the severe beaming pattern associated with two acoustic sources. Approximately 800 Hz acoustic crossover provided the best of all three requirements listed above. I like to let the speaker components tell me where they would like to be crossed over.

roy "

[Edgar]

"I like to let the speaker components tell me where they would like to be crossed over."

Thank you. It's tough to argue with reality. "When reality disagrees with theory, get a new theory."

Edgar

[Edgar]

Couple of things: first there are 2-12" drivers in the Jubilee, so the efficiency is doubled automatically. This raises the upper frequency corner based on the decibel rating, of course.

But the tide lifts all boats. Raising the efficiency should just raise the entire response curve.

second, the Keele mass rolloff equation in question puts the K33E at 177 Hz, yet it crosses over effectively in the Khorn at approx. 400Hz. I have always found this confusing, but the K33E is not operated at full efficiency in the Khorn, either. Increasing the reactance applied to the driver (in this particular case) widens the bandwidth.

My numbers show fHM for the K-33-E to be 88 Hz, based upon fs=28 Hz and Qts=0.633.

Third, the Jubilee has folds that are optimized to pass  higher frequencies than is the Khorn.

The USABLE high frequency corner is much higher than the simple math result would indicate.

There is obviously more going on here than meets the eye.

Thanks,

Edgar

[Edgar]

Those numbers are at least one octave lower than I would have expected.

From Keele; fHM = 2fs/Qts. It is possible that I have the wrong numbers for the TS parameters, but I found most of them in this forum.

Edgar

[Guest " "]

Those numbers are at least one octave lower than I would have expected.

From Keele; fHM = 2fs/Qts. It is possible that I have the wrong numbers for the TS parameters, but I found most of them in this forum.

Edgar

I am not questioning your methods.

I never took the time to dig that deep, had I, I would be just as surprised.

I would have expected an 18 inch driver to behave with the data being indicated for the 12 inch drivers.

I may be a little spoiled. I spent my early years with PA drivers that have a very wide range.

[bodcaw boy]

Keele's equations do not take into consideration directivity and effieciency gain as you go up in frequency. Horns and even direct radiators have coverage patterns that kinda act like an eq boost as you go up in freq. And as you go up in freq, the diap or horn mouth acts like a baffle to load the wave better until you get close to the diameter of the voicecoil or in a bent horn's case, uneven path length differences. Even that assumes that the diap is staying rigid.

[DrWho]

Hey there, welcome to the forum!

Here are some specs on the Jubilee taken from the cinema brochure. And apparently even better HF extension can be achieved by going with a 69 driver instead of the standard 1132.

[DrWho]

I also forgot to mention that those are 1/2 space measurements - so

when you move to 1/8 space Roy tells me that the response curves

smoothen up. The Jubilee is better than the khorn in all aspects except

32Hz - 42Hz...but in either case I'd argue you still need a sub so no

biggy.

[Duke Spinner]

be interesting to see that overlap curve, 500-800 hz

[DrWho]

Tis really smooth actually...If I remember correctly both the bass bin and HF section have small peaks on the other side of the crossover. Roy was using 600Hz 24dB/octave for the passive with a few extra traps to try and smooth it out even more.

[WMcD]

I'm glad that Roy confirms something I've been saying for years. Not that I'm speaking for him here.

1) Many horn shapes have radiation patterns which narrow as frequency goes up. Some of this is due to the geometry of the interior of the horn and some of it is mouth size. Mouth size or just a diaphragm does this simply because at high frequencies they are bigger antenna in terms of wavelength.

2) Olson's diagrams showed the narrowing but the diagrams seem to have been normalize to show on axis response to be constant. I think in reality there is gain on axis as frequency goes up.

3) Drivers used on horns have decreasing output as frequency goes up, just as Keele says. You see this when driver response on a plane wave tube is shown (about 3 kHz. But very often the response is shown on a horn with that increasing on axis gain..

4) You put 2 and 3 together and you get a type of equalization.

5) Constant directivity horns do not have as much change, as shown by Keele. Note that he had to equalize the driver to a constant output, and then the horn output was constant.

6) Horns like the K-400 keep the horizontal pattern fairly constant and the vertical pattern narrows. PWK called it controlled directivity. So it too has some gain on axis.

7) You see the 9 kHz "glitch" in the K-55. It may be diaphragm break up. It is about, say 15 dB down without the horn. But the horn has so much on axis gain it is can be heard. It may be that something similar is happening in the Jubilee. So it is necessary to eventually have a steep electrical filter.

8) The K-Horn is probably lossy at 400 Hz and above due to the second section where the path flips from horizontal to the vertical. However the real problem may be that final sections face away from the front axis and there is little gain at 400 Hz and above. If you look at the AES paper on the Jubilee, the design evolution is to have the final flares face more forward. Hence rising gain.

9) Keele calculates an increasing rate of roll off in the driver and you see this in midrange drivers on plane wave tubes. While a horn has some increasing gain, it can't keep up with it quite as much as the driver is rolling off. So at some point the overall response drops very quickly.

Gil

2) The drivers