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Multi-Way Conventional loudspeakers with crossovers

Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
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Old 18th November 2019, 06:10 AM   #4411
camplo is offline camplo
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Quote:
Originally Posted by Robh3606 View Post
I am no expert but it can't be simply a matter of length if so how do you explain the "loading" in shallow waveguides like the PT's or M2?
Because they lie. They take advantage of the fact that for non pa, loading isn't usually a factor. Loading "should" be a length of 1/2WL or better, but you'll see products going 1/4th and smaller. Kinda like posting measurements for an amp thats 1000watts without specifying if its rms or max or in what ohms. They also sell the 8" woofer to 1" tweeter two way.

Last edited by camplo; 18th November 2019 at 06:18 AM.
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Old 18th November 2019, 06:16 AM   #4412
Ro808 is offline Ro808  Netherlands
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Quote:
Originally Posted by Robh3606 View Post
I am no expert but it can't be simply a matter of length if so how do you explain the "loading" in shallow waveguides like the PT's or M2? They are only a couples of inches deep. 3.25" for a PTH1010. With a large format driver you can get a very usable 800-900Hz crossover point.

Rob
It's still is a matter of axial length, even for the M2 waveguide.
Charles Prinkle came up with some clever solutions to 'mimic' a deeper horn in a shallow waveguide.
The function of the M2's knuckles is somewhat similar to the mumps in the Klipsch K510 shown previously.
The M2 WG relies on a diffraction aperture to push the wavefront across the (flattened/brought down) curvy mouth section.

I guess it's best illustrated in this drawing:

Click the image to open in full size.

Last edited by Ro808; 18th November 2019 at 06:24 AM.
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Old 18th November 2019, 06:17 AM   #4413
camplo is offline camplo
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Originally Posted by Ro808 View Post
Loading is an aspect of flare/contour and axial length vs. coverage angle(s) > narrow coverage requires a deeper horn.

So what I said was true bet yet an over simplification. From what I'm gathering, generally speaking you are not going to escape a direct tie between length and loading, if flare/contour is of the same nature between two horns. So after you've chose a type, say JMLC and chosen a flare rate which I believe is T, length is the governing aspect directly resulting in a Fc

If I understand some what, the M2 creates a deeper horn without the appearance of such or at least, creates acoustical impedance in the throat.

Last edited by camplo; 18th November 2019 at 06:21 AM.
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Old 18th November 2019, 06:23 AM   #4414
Ro808 is offline Ro808  Netherlands
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All true.
Despite the nifty tricks, the M2 waveguide is still shallow
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Old 18th November 2019, 06:26 AM   #4415
camplo is offline camplo
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So now, we can create a horn that ends in the desired length and with the complying contour and flare rate, we truncate the mouth flare....we are almost at the Jericho 45....and this comes with the punishment of turbulence in the frequency response, some where in the polar if not on axis? The Jericho 45 is pretty smooth given that its mouth termination is on the abrupt side.
Ro808, what are your personal thoughts on the Last Jericho, Jericho 45 we'll call it. It beams, its a sacrifice...but looking at the impedance chart, is that what I want to see?

Last edited by camplo; 18th November 2019 at 06:34 AM.
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Old 18th November 2019, 06:48 AM   #4416
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Originally Posted by docali View Post
@camplo

Here is a small video Don prepared during our evaluation or call it proof of concept phase. This is a spherical wave horn with T=1, stretch factor of 1.5 and stereophic projection applied. I am quite sure that this horn would work nicely.

So, if you choose a constant T factor this is similar to the spherical wave horn properties and we know that these horns work as several Klangfilm cinema speakers used this horn type.

Attachment 795315
Watching this animation immediately made me think of when someone was describing how it sounded on a horn that was crossed too low, as if the sound was coming from some where inside the throat. If you look at this animation you can see the sound pressure front initiate inside the throat and eventually make its way out.
The Jericho 45 does not have this issue at 200hz. Me so happy.
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Old 18th November 2019, 07:07 AM   #4417
Ro808 is offline Ro808  Netherlands
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A diffraction slot is an effective means to shorten the horn's axial length (and increasing coverage angles).

If you look at JBL's 2380 Bi-Radial series, you'll find the narrow beamwidth 2360a (practically) omits a slot.
The 2380a's usable low frequency limit of 350 Hz is only 50Hz below the limit of its slotted brothers, but its depth is 35.9cm vs. 23.6cm for the 2380a/2382a.

Last edited by Ro808; 18th November 2019 at 07:10 AM.
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Old 18th November 2019, 07:18 AM   #4418
Ro808 is offline Ro808  Netherlands
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Quote:
Originally Posted by camplo View Post
Ro808, what are your personal thoughts on the Last Jericho, Jericho 45 we'll call it. It beams, its a sacrifice...but looking at the impedance chart, is that what I want to see?
Bearing in mind the limitations, I think nearly all the horns as presented by Docali and simulated by DonVK, are excellent with regards to impedance/loading characteristics.
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Old 18th November 2019, 12:24 PM   #4419
AllenB is offline AllenB  Australia
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Is it possible to cover the whole spectrum, high spl, low distortion with a 2-way?
Quote:
Originally Posted by camplo View Post
Because they lie.
Maybe it's something else. Waveguides may be listed by a frequency which they can reasonably constrain for directivity purposes. Of course that isn't what loading means, but why do many speakers list only one T/S parameter.. Watts?
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Old 18th November 2019, 12:48 PM   #4420
Ro808 is offline Ro808  Netherlands
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You hardly see any true horns in modern commercial PA products for reasons of directivity. .
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