Horn vs. Waveguide

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#41
Rybaudio said:


The on-axis response for the ESP12 doesn't matter because it's such a tiny part of the soundfield radiated by the speaker... suppose the hole is there for a 5 degree cone... that's only .2% of the area sound is radiated into, and, approximating the soundfield by a 90 degree cone, that's about 1% of the radiated sound. However, the response of the JBL at say 45 degrees off axis is hugely important because it's a major part of the soundfield radiated by the horn.



I would say no, the idea is to have the response radiated at all angles, which constitutues the direct sound, early reflections, late reflections, and power response, which together determine the tonality of the system, flat and smooth. The direct sound, while important, is only part of the equation.
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The hole in the response according to the measurements gedlee posted is with in 30-40 degrees on axis, this is where the majority of the energy is and the most non linear part of the gedlee horn.
 
#42
quote:
Originally posted by FrankWW
The idea is to have a wide sweet spot, no?

I would say no, the idea is to have the response radiated at all angles, which constitutues the direct sound, early reflections, late reflections, and power response, which together determine the tonality of the system, flat and smooth. The direct sound, while important, is only part of the equation.
If the idea is as you say, then you will have a wide sweet spot.
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#43
O.K., let's all pretend that the direct sound from the speakers, whether that is coming from on their axes, or some off-axis angle thereof, is not of primary import. 🙄

The point of uniform power response is to insure that the secondary, reflected sound is similar in sonic character....
 
#44
ZilchLab said:
O.K., let's all pretend that the direct sound from the speakers is not of primary import. 🙄

The point of uniform power response is to insure that the secondary, reflected sound is similar in sonic character....
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In this case it is not because the direct sound (the loudest, highest energy) is non linear 😱
 
#45
Magnetar said:



In this case it is not because the direct sound (the loudest, highest energy) is non linear 😱
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I THINK we're in agreement here. The direct sound is only on-axis if the speaker is pointed at the listener.

Gedlee doesn't listen that way, he said above. He listens off-axis, so the non-linear on-axis sound of his waveguides goes elsewhere, past him, to the rear of the space, presumably....
 
#46
ZilchLab said:
O.K., let's all pretend that the direct sound from the speakers, whether that is coming from on their axes, or some off-axis angle thereof, is not of primary import. 🙄

The point of uniform power response is to insure that the secondary, reflected sound is similar in sonic character....
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I agree with the second paragraph. But with the first one I do not - the direct sound should be the most important (IMO), but that does not necessitate listening at 0 degrees from the horizontal axis.
 
#47
ZilchLab said:


I THINK we're in agreement here. The direct sound is only on-axis if the speaker is pointed at the listener.

Gedlee doesn't listen that way, he said above. He listens off-axis, so the non-linear on-axis sound of his waveguides goes elsewhere, past him, to the rear of the space, presumably....
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Not true - the on axis output as shown in the graph is some 3 to 15 db higher that is being radiated off axis - second the hole in this particular horn (gedlee) is within 30 to 40 degrees on axis. This is a wide axis not a narrow one. The measurments are taken at 7.5 degree intervals - times 2...

I don't think he likes to talk about listening.:hot:
 
#48
454Casull said:

I agree with the second paragraph. But with the first one I do not - the direct sound should be the most important (IMO), but that does not necessitate listening at 0 degrees from the horizontal axis.
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I THINK that's what "... whether that is coming from on their axes, or some off-axis angle thereof, ..." means.

[Where's Gedlee when I need him...? 😉 ]
 
#49
Poeple should read the SUMMA white paper. It says so much more than I can express here in a post.

The listener in my setup is at about 22.5 degrees well out of the axial hole. The speaker axes cross well in front of the listener and no one in the room is ever on axis.

With CD this can be done (and only with CD) and represents what JBL tried to do many years ago with the Everest project (although horn technology back then was not up to snuff) - a system whose level falls off as one gets off axis and closer to it. This maintains a very stable image across a very wide range of seating locations.

Image is very dependent on the direct field and the direct sound frequency response is critical. At 22 ° off axis the ESP speakers are +- about 1 dB, but they also have very smooth power response so that the reverberation field and hence the coloration from this field (lack of coloration actually) is also flat.

Again - READ THE PAPER.
 
#50
gedlee said:
Poeple should read the SUMMA white paper. It says so much more than I can express here in a post.

The listener in my setup is at about 22.5 degrees well out of the axial hole. The speaker axes cross well in front of the listener and no one in the room is ever on axis.

With CD this can be done (and only with CD) and represents what JBL tried to do many years ago with the Everest project (although horn technology back then was not up to snuff) - a system whose level falls off as one gets off axis and closer to it. This maintains a very stable image across a very wide range of seating locations.

Image is very dependent on the direct field and the direct sound frequency response is critical. At 22 ° off axis the ESP speakers are +- about 1 dB, but they also have very smooth power response so that the reverberation field and hence the coloration from this field (lack of coloration actually) is also flat.

Again - READ THE PAPER.
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I read it a minute ago and find it contradictory.
 
#51
Magnetar said:



Not true - the on axis output as shown in the graph is some 3 to 15 db higher that is being radiated off axis - second the hole in this particular horn (gedlee) is within 30 to 40 degrees on axis. This is a wide axis not a narrow one. The measurments are taken at 7.5 degree intervals - times 2...
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Well, I'm not seeing that. It's 7.5 dB deep on-axis, worst case, and is gone by 15° off axis.

Equilateral triangle, listener is 30° off-axis and outside that window, no?
 
#53
What graph are you referring to? I don't see it in what he's posted here or on the Ai site. Are we looking at the same thing?


The hole in the response according to the measurements gedlee posted is with in 30-40 degrees on axis, this is where the majority of the energy is and the most non linear part of the gedlee horn.
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#55
FrankWW said:
What graph are you referring to? I don't see it in what he's posted here or on the Ai site. Are we looking at the same thing?
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In the original post the manufacture posted a plot showing a deep notch or hole at 7.5 and 15 degrees. This is actually 15 and 30 degrees when looking at the center axis of the speaker - so let's just say they are very nonlinear op to 30 degrees in all directions= The output in this region is many times higher (direct sound) then the off axis (smooth) output -The on axis and off axis response is also very different. Here lies one contradiction.
 
#56
The toe in is at 45°. The listener will be at about 20 - 40 °. The directivity pattern thus misses the near wall reducing this, the earliest refection and the most problematic, to almost nothing. The first major reflection is off the far wall and that arrives at the ear opposit to the ear that receives the direct sound. Tis prevents the comb filtering that causes coloration. If you map it out you will see how it works.
 
#57
gedlee said:
The toe in is at 45°. The listener will be at about 20 - 40 °. The directivity pattern thus misses the near wall reducing this, the earliest refection and the most problematic, to almost nothing. The first major reflection is off the far wall and that arrives at the ear opposit to the ear that receives the direct sound. Tis prevents the comb filtering that causes coloration. If you map it out you will see how it works.
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What did you do about the comb filtering or cancellation from the cross talk between the speakers?
 
#58
gedlee said:


With CD this can be done (and only with CD) and represents what JBL tried to do many years ago with the Everest project (although horn technology back then was not up to snuff) - a system whose level falls off as one gets off axis and closer to it. This maintains a very stable image across a very wide range of seating locations.
Click to expand...

Also S2600 and S3100, sold primarily internationally. And, more recently, a MKII version:

http://manuals.harman.com/JBL/HOM/Technical Sheet/JBL S3100 MKII rev0 ts.pdf

Very cool, but I think marketing types decided they'd sell more speakers if they dropped the concept in favor of a center channel, instead. Nobody got it, anyway....
 
#59
ZilchLab said:


Also S2600 and S3100, sold primarily internationally. And, more recently, a MKII version:

http://manuals.harman.com/JBL/HOM/Technical Sheet/JBL S3100 MKII rev0 ts.pdf

Very cool, but I think marketing types decided they'd sell more speakers if they dropped the concept in favor of a center channel, instead. Nobody got it, anyway....
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Western, Lansing, Klangfim, ect. were working on horn's power response or controlled directivity some 70 years ago.

I like to extend it into the bass.


An externally hosted image should be here but it was not working when we last tested it.


An externally hosted image should be here but it was not working when we last tested it.
 
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