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mikebse2a3

Klipschorn Jubilee (Babies First Sounds)

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Well the babies are begining to make some sounds and it is impressive!!!!

Since I'm waiting on the EV-Dx38 electronic crossover to arrive for full range sound I thought why not check the sound of the Jubilee Bass Horns out.

The following is just with the Bass Sections Playing.

Well I planned on using my Cary CAD-2A3i (2A3 Push/Pull Amplifier) for the Low Frequency Horns and was curious how well it would work as far as Hum and Noise as well as other factors considering the very high efficiency of the Jubilee.

WHAT HUM/NOISE!!!! I'm pleased to say that with my ears at the mouth of the Bass Horns there was NO HUM or Noise of any kind!!![:D]

I promised myself the First Sounds from the Jubilees was going to be Muddy Waters (folk singer) and Buddy Guy (Blues Singer) and I was really suprised at how high in frequency these Bass Horns can reach. Again Very Impressive!! especially if you have ever just listened to a Klipschorn's Bass Horn playing by itself. These Horns easily reach well above 1.25kHz very cleanly!

So next I thought lets run some Test from the stereophile Test CD2. I played track 16 and 17 which is 1/3 octave warble tones from 20Hz to 2kHz. All I can say is WOW!!! the Jubilee can sure reach easily down to 31.5Hz with a (smoothness and strength) that I was not able to get out of the 79 Khorns in this room. The Center Image Focus when playing Left/Right Jubilees together was also much better than I was able to acheive with the 79Khorns again in this room. The Jubilee by Design is proving to me that IMHO it is going to be much more room friendly as well as taking better control over the rooms acoustical problems. At least in my situation this is already the case.

Now I really can't wait to GET FULL RANGE SOUND OUT OF THESE BABIES!!!![:D]

mike tn[:)]

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You want me to come over and sing suprano while you're playing the bass bins?

I think after my wife kicks me I'll be able to hit the high notes effortlessly!!

[6]

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Guest " "

Great report

The upper bandwidth test is very intresting.

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Mike, what are the dimensions of your room? It'd be interesting to see some frequency response plots and compare them to the anechoic plots Roy posted. I can imagine that room gain is certainly helping to extend and flatten that low frequency response. And you should get some extra coupling of the LF by running two bass bins too.

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You want me to come over and sing suprano while you're playing the bass bins?

I think after my wife kicks me I'll be able to hit the high notes effortlessly!!

[6]

Richard I have a feeling your going to be tied up building that Home Theater Room for a while!!![:o]

mike tn

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Mike, what are the dimensions of your room? It'd be interesting to see some frequency response plots and compare them to the anechoic plots Roy posted. I can imagine that room gain is certainly helping to extend and flatten that low frequency response. And you should get some extra coupling of the LF by running two bass bins too.

Well the room dimensions are approximately 12' x (15' to 20') with 8' ceiling.

Mike no doubt the room is having some influence over the sound I'm getting but what I would like to really point out is how the Jubilee Performs in this room versus how my 79 Khorns performed in the same enviroment. As good as any speaker test in an anechoic enviroment when it comes down to its just as important in how it integrates with the room acoustics.

The most Important observation so far is that the Jubilee seems to be more independent of the room or put another way it couples better to this room to offer a smoother response with what sounds like more Low Frequency Extension than the 79 Khorn did in this room. Its hard to put into words but there is just an "Effortless Quality" to the sound which the 79 Khorn has to some degree but the Jubilee has this quality even more in my room.

mike tn[:)]

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You will perhaps pardon me if I hope I experience the same things when I (finally) get mine hooked up.

Reading about your thoughts here are getting me even more interested in getting that done sooner than Friday. Alas, I have a birthday party to attend tonight in Vonore so it just ain't gonna happen.

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thanks for the post, very interesting. keeps making me think I can cross at 1khz instead of lower down.

please play with the crossover points a bit once your electronic crossover gets there, it will be very interesting to some of us who plan to DIY the bass bin and are still wondering over where to crossover.

regards,

tony

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What you are reporting makes sense to me.

Two things are going on - the Jubilee has a bigger mouth area than the Khorn, sized between 1/4 and 1/8th space and therefore makes less demands on "clear" wall length than the Khorn, comparitively. The propagation characteristics are different due to the splay angles of the Jub mouth, too.

As for going as low, the Khorn on technical merits should win out in an environment suitable for its best propagation, it has a longer horn pathway, which in horns, is a characteristic that is perhaps the most important thing for a smooth response after an appropriate mouth size.

The Jubilee is not as likely to provide as smooth of a LF response as the Khorn is capable of (in the "right" environment) simply due to it having a shorter horn pathlength and a slightly larger overall throat size (comparitively speaking).

However, like it has been mentioned, certain rooms are not optimum for the rather demanding Khorn. So it is indeed quite likely that the Jubilee is a better overall acoustic match to "most" listening spaces.

The Jubilee is more subject to diffraction events than the Khorn in that there are cavity spaces around the mouth when placed in a corner. I beleive that this is why the Jubilee paper states that the LF response is diminished or lessened somewhat when placed in a corner.

The trade off is that it can crossover higher, and due to the folding in a consistant plane, the available transient response should expectedly be more consistant, as phase information is "retained" to a larger degree.

DM

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Have you looked at the measurements? I'd say the reason for percieved better integration with the room has

to do with the roll-off on the low end.

The khorn simply has an ugly frequency response and though its more efficient in the 30-40Hz region, its a result of a peak in the response - not a natural roll-off. The Jubilee is a near perfect 12dB/octave drop off below 50Hz which mates real well with the natural 12dB/octave room gain. And from 50Hz to 100Hz the Jubilee is owning the khorn (which happens to be the region where more low frequency content resides).

The model shows room gain starting at 40Hz which lines up nearly perfect with the Jubilee. He should get solid reponse down to 30Hz if not lower...I suppose the same could be argued for the khorn, but it'll be lacking in the more important 50-100Hz region.

Btw, Roy mentioned on several occasions that the low-end becomes smoother when mounted in the corner. Probably because the horn appears to be larger than it is (thus better loading of the driver).

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DM said:

The Jubilee is more subject to diffraction events than the Khorn in that there are cavity spaces around the mouth when placed in a corner. I beleive that this is why the Jubilee paper states that the LF response is diminished or lessened somewhat when placed in a corner.

-------------------------------

The AES Paper states:

" The design still recognizes the fact it will be loaded in one-eight space but does not absolutely require that a corner be avaible for proper operation."

"Apparently the mouth area that is available is sufficient to load the drivers down to 40Hz. From Fig. 8, the -3db down point is approximately 40Hz. The fact that the horn will be operated in rooms helps overcome the shortage in mouth area. In true one-eighth space loading, the output in the 35-40Hz region will decrease."

Dana I believe what the paper is stating is in a TRUE one-eighth space (ie: like an outdoors with corner loading which means the possible benefits of room loading isn't available. So the way I'm reading the AES Paper is that the Jubilee works best when located in a corner and can benefit from the room's acoustics.

As the paper states "Considering all the possible variables that must match, the final layout offers the soultion that contains the fewest compromises and produces the most benefits."

mike tn[:)]

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Mike, don't be taking this the wrong way, I've just been analyzing some of the differences between the Jubilee and the Khorn, that's all.

It is true it was measured outdoors, however, a "true" 1/8 space is a pi/2 (or 1/8th of a sphere) radiation angle, it would occur in both indoor and outdoor spaces (doesn't matter) where the perpandicular intersecting walls and floor are high/long enough to form a boundary compared to mouthsize for practical purposes. The size of the 1/8th space radiation angle is determined by boundary limits (ceiling, wall length, etc.).

The only thing that you won't get outdoors is the "room" gain or any benefit from modes or reflections, as well as the ability of an enclosed space to build up and store acoustic energy like a capacitance. Other differences of outdoor testing is caused by variances in humidity, temperature and an unrestricted (or infinite) volume of air that is likely to be somewhat unstable (windy) do to thermal considerations; there is much higher absorption. It's a true anechoic chamber, meaning simply that there are no echoes.

However, what I am saying is that the Jubilee mouth is not a perfect match to the 1/8 space environment, that is a trade off of the splay angles employed COMPARED to the Khorn.

A 1/8th space radiation angle (either indoors or outdoors) looks like this (attached) - I drew a rather bad drawing of what I'm trying to say.

The cavity spaces on the sides of the terminal exits caused by the splay angles of the Jubilee mouth are subject to diffraction. No way around that one. That entails a loss of acoustic energy (small, but there). For an example, see the LB76 patent with wings to prevent that to a degree. Am I saying that the Jubilee needs that? No. Just making a comparison with the Khorn, that's all, which by its way of becoming part of the corner itself, is not subject to diffraction around the sides.

The wavelengths being reinforced by planer reflections are another matter. That is frequency-specific, as long as the waveform is 0.75 wavelengths or closer to the reflective surface, and that means only the upper frequencies would be subject to fall off there (LF wavelenths are very long, of course). That would be for example, 19 inches for 500Hz, 12" for 800Hz, etc.

So it can be seen that the falloff of reinforcing reflections would start around 900Hz for 11" distance from the side walls. I don't know what the actual distance is between the exit channel side and the nearest wall, that measurement would be critical in determining the best crossover point. Also, natural diffraction could be somewhat helpful in this case.

Dana

post-13458-13819307451516_thumb.jpg

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Thanks for posting that Dana...I wasn't getting your diffraction comments until seeing the picture.

One thing I've always wondered about is the diffraction across the face of the speaker (what you labeled the shadow area).

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I've often wondered about the actual effect of the front baffle.

The central planar baffle on the front of all side-firing bifurcated corner horns is an important point - it prevents waveform curl-around at the horn terminal exits, near as I can figure. A handheld SPL meter should indicate the actual distances and overall pattern of the diffractional elements.

I don't have one, but it would certainly be cool if somebody here mapped it all out for us!

Dana

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Mike, I would like to say that your opinions of the differences are very interesting, since you are familiar not only with the room and its "idiosyncracies", but especially because you have and are used to Khorns in the same room, in the same placement!

This is as close to a A-B test of these two interesting designs that most of us will ever get, so your opinions are VERY IMPORTANT!

Don't let my blabbering about technical crap stop you - Keep posting your opinions and impressions!

Dana

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Mike, don't be taking this the wrong way, I've just been analyzing some of the differences between the Jubilee and the Khorn, that's all.

Dana I'm not taking anything the wrong way and as a matter of fact I reread the paragraph twice before it dawned on me what was being stated.[:)] I really enjoy a conversation like this as long as people take things in the right way.

It is true it was measured outdoors, however, a "true" 1/8 space is a pi/2 (or 1/8th of a sphere) radiation angle, it would occur in both indoor and outdoor spaces (doesn't matter) where the perpandicular intersecting walls and floor are high/long enough to form a boundary compared to mouthsize for practical purposes. The size of the 1/8th space radiation angle is determined by boundary limits (ceiling, wall length, etc.).

I agree to a certain frequency this is true up until the ceiling/sidewalls/backwalls become a substantial portion of the wavelength. Which at the 35-40Hz mentioned it would definitly not be a true 1/8th space.

The only thing that you won't get outdoors is the "room" gain or any benefit from modes or reflections, as well as the ability of an enclosed space to build up and store acoustic energy like a capacitance. Other differences of outdoor testing is caused by variances in humidity, temperature and an unrestricted (or infinite) volume of air that is likely to be somewhat unstable (windy) do to thermal considerations; there is much higher absorption. It's a true anechoic chamber, meaning simply that there are no echoes.

However, what I am saying is that the Jubilee mouth is not a perfect match to the 1/8 space environment, that is a trade off of the splay angles employed COMPARED to the Khorn.

I don't believe the Khorn mouth is a perfect match to the 1/8th space either due to the fact that the Horn's Mouths don't completely go from frontwall to sidewall in the corner but is spaced by the front baffle which because of that dimensions(as well as other things) does cause some of the High Frequency Rolloff of the standard Khorn as evidence by the prototype Roy and PWK had built before learning the benefits to reduceing this dimension. I also believe anytime the wave is interfered with there will be some diffraction effects due to reinforcement and cancelation. Think Reflection Phase Grating Diffusers for example work on this principle. Again the Khorn is a compromise also in my view.

A 1/8th space radiation angle (either indoors or outdoors) looks like this (attached) - I drew a rather bad drawing of what I'm trying to say.

The cavity spaces on the sides of the terminal exits caused by the splay angles of the Jubilee mouth are subject to diffraction. No way around that one. That entails a loss of acoustic energy (small, but there). For an example, see the LB76 patent with wings to prevent that to a degree. Am I saying that the Jubilee needs that? No. Just making a comparison with the Khorn, that's all, which by its way of becoming part of the corner itself, is not subject to diffraction around the sides.

I agree that as you state there is some diffraction to the sides but because the cavity is triangular in shape it's effect will be spread over a certain bandwidth, time and of less amplitude. So its true effect depending on frequency would cause some roughening in response but again from some of the test I've seen it seems to be mild and well worth the compromise.

The Khorn has its on issues with boundry effects and again overall displays a rougher response.

The wavelengths being reinforced by planer reflections are another matter. That is frequency-specific, as long as the waveform is 0.75 wavelengths or closer to the reflective surface, and that means only the upper frequencies would be subject to fall off there (LF wavelenths are very long, of course). That would be for example, 19 inches for 500Hz, 12" for 800Hz, etc.

So it can be seen that the falloff of reinforcing reflections would start around 900Hz for 11" distance from the side walls. I don't know what the actual distance is between the exit channel side and the nearest wall, that measurement would be critical in determining the best crossover point. Also, natural diffraction could be somewhat helpful in this case.

Dana

Again your thoughts are appreciated on this Dana.[:)]

mike tn

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Tell us what you think of the low end? The "weight" and "solidity"? Overall depth? etc.

Impact, sense of dynamism? How do they compare?

I have a couple of very specific things that I'm interested in, since my horn is folded like a Jubilee but has the splay angles of a Khorn.

I'm looking for the differences you perceive in having 2x12" drivers vs. a single 15". I am familiar with the sound of a K33E. I agree that it has a certain sense of transparency that is pretty unique, etc.

Dana

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One point I would like to make is if you view the Jubilee as an improved Klipschorn(Which I certainly do) then IMHO it is because the Design was able to stand on the "Shoulders of the orginal Mighty Klipschorn" which still deserves alot of respect!

mike tn[:)]

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Of course I enjoy reading comments from Dana and Mike. All insights are welcome.

I'll throw in some of my own.

1) Roy and Paul describe the Jubilee as a 38 Hz Fc horn. The table in the article starts with the throat area and goes to the mouth in a cumulative fashion.

In my view that obscures an important aspect. After the short initial flare, the Fc is lower. I had posted a spread sheet to make calculations. I haven't played with this recently. However, I'm confident that if you plug in numbers ignoring the first expansion, you'll find a 30 or lower Fc.

This part of the implication of the rubber throat idea.

I'll assume that what they say about the K-Horn is correct. It is a 38 Hz Fc horn. So the Jubilee has an advantage.

Some of this may be lost if the path lenght is shorter. Hard to tell. As pointed out by others, even otherwise optimized horns suffer when the lenght is shortened.

2) The increased mouth size of the Jubilee is another advantage. I believe it is bigger in relation to any Fc you pick.

Don Keele's paper on optimum mouth size has an interesting piece of data. It is that optimum mouth size (we may not quite be there, but closer) causes a better match condition below Fc in addition to above it. (Gamma (?) goes flat in one of the graphs.) It is something to keep in mind.

3) I don't disagree about room effects. In addition to room modes, reflections, etc. there may be an additional factor. It is that we could remove the two walls which are opposite the horn to make a room with two walls and the floor and ceiling.

It seems to me that this makes a horn extension with its own qualities. It is better than just outdoor 1/8th space. And we're not even talking about reflections.

Mike talks about mutual coupling with an additional corner horn. Maybe this could be viewed as creating a wall, if soft wall, running the length of room between the corner horns, where the pressure waves meet, in phase. If so, we're dealing with any one horn looking into a long tube after some corner effects.

Naturally any of this applies to any two speakers in their repective corners. Still it is an alternate way of thinking.

Best,

Gil

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