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Multi-Way Conventional loudspeakers with crossovers

Combining a 2" exit driver with a HF unit as a point source. Is it possible?
Combining a 2" exit driver with a HF unit as a point source. Is it possible?
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Old 9th January 2020, 08:39 PM   #21
tmuikku is offline tmuikku  Finland
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Can't comment on that sim, but you could experiment with the system in mono with the DSP you have to save on passive xover components.

If you have a rotating measurement jig you should take (full) horizontal and vertical measurements and checkout the xover in VituixCAD. Power response and good polar views will help you to tune the xover and sound.

Before cutting a hole to the mid horn you could try different positions and angles of the K-tube in front of the horn. If you hear significant difference in sound depending where the tube points at you just made a better speaker For this experiment you could questimate a crossover with DSP.

Anyway, trying out stuff before committing will teach you a lot and lead to better sounding design.

It is cool to see what you come up with and how it will sound!

Have fun!
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Old 9th January 2020, 08:44 PM   #22
pelanj is offline pelanj  Czech Republic
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Combining a 2" exit driver with a HF unit as a point source. Is it possible?
Yes, absolute levels are off by some 8-10 dB, you are right. I will try to reverse the resistors if there will be any difference. I think I tried both and there was not much of it. I imported also the measured impedance to XSim. Thanks for your help! Edit: Thanks go to both My measurements are not very professional, but I try I had the tube on top of the horns for a while, it did not catch up to the JBL2445 sensitivity and it was at the times with a passive crossover.

Last edited by pelanj; 9th January 2020 at 08:50 PM.
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Old 10th January 2020, 05:05 PM   #23
pelanj is offline pelanj  Czech Republic
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Combining a 2" exit driver with a HF unit as a point source. Is it possible?
Stage one of this project will be printing mockups of the KTube part that will stick out inside the horn and I will try to measure the influence on the response, trying to get it as close to the throat as possible. This will be done in two sizes, one for 1" ID tube and one for 0.5" ID tube that would be suitable e.g for DE5. I will need to make a proper turn table.

What is the correct rotation point? Middle of the mouth, at the middle of the 2445
membrane, at the bug screen (end of the phase plug) or somewhere else?
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Old 10th January 2020, 08:21 PM   #24
tmuikku is offline tmuikku  Finland
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Google search "vituixcad measurement preparations" document, all should be there. I think there is separate document for ARTA and for REW. With that guide you should be able to get good data in home environment.

Speaker frontpanel should be used for rotation center, so mouth in this case.

Turntable can be as simple as two pieces or ply with loose screw as center. Anything more slippery than ply will rotate easier, melamine surface (cheap furniture panels) for example. Or put some marbles on a round groove between the panels. It is all good as long as the DUT and mic stay in place when you turn

Last edited by tmuikku; 10th January 2020 at 08:26 PM.
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Old 10th January 2020, 08:36 PM   #25
pelanj is offline pelanj  Czech Republic
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Combining a 2" exit driver with a HF unit as a point source. Is it possible?
I used a speaker stand until now. But I need something more heavy duty for the horns. As I see it, the turntable should have a straight front or I need to make sime fixture so I do not get reflections.
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Old 10th January 2020, 09:16 PM   #26
tmuikku is offline tmuikku  Finland
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You can put the turntable on the floor and speaker stand on top of it. But yeah, the turntable quickly gets pretty large.. I have speaker about one meter high and weird shape, almost meter wide, weights a lot. really difficult to measure. Butchered a dolly cart, round ply taped to the floor undernetaath providing the angle scale and center point. Then ratchet strap the speaker on a makeshift stand on the dolly, use long steel bar as center pin, attached to the dolly, and another to point the angle. Pretty easy to turn around but easily a centimeter or two of since the jig isn't very stable. But, havent figured out better rig yet I think it would be easier to move the mic
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Old 10th January 2020, 11:21 PM   #27
pelanj is offline pelanj  Czech Republic
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Combining a 2" exit driver with a HF unit as a point source. Is it possible?
There are not too many options of how to install the K-tube of this size. Of course, the mounting plate will be outside and the foam is just a support for taking pictures. It seems when I place the tube as close to the mouth as possible to fit the HF driver, it should be just about the right length and angle based on previous experience. It will be some fun to drill the hole properly...
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Old 11th January 2020, 01:03 AM   #28
freddi is offline freddi  United States
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Combining a 2" exit driver with a HF unit as a point source. Is it possible?
- cool - will be an interesting experiment - what drivers will be involved?

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Old 11th January 2020, 11:26 AM   #29
pelanj is offline pelanj  Czech Republic
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Combining a 2" exit driver with a HF unit as a point source. Is it possible?
Beyma CP385/Nd, since that is what I have at the moment and it is really good. And JBL2445 for midrange. A hole is drilled and new K-Tube with updated dimensions is being printed Drilling the hole was quite easy with a 32 mm hole saw. The material is easy to work on.
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Last edited by pelanj; 11th January 2020 at 11:28 AM.
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Old 11th January 2020, 08:21 PM   #30
pelanj is offline pelanj  Czech Republic
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Combining a 2" exit driver with a HF unit as a point source. Is it possible?
So the K-Tube is printed and installed in the horn. I could not resist and made some measurements on axis. I will not show them yet, they make exactly zero sense to me. I need to do the measurements outside, inside my cluttered workshop it seems not to work. Subjectively, the tube seems to do something and the HF in the far field is extended, when playing both together. The tube inside the horn does not seem to influence the mid driver response much if at all. The tube response is falling at a similar rate as the mid, but higher. That would indicate that the chosen angle is way off...I hope I will have a chance to measure outside tomorrow. Unfortunately, a different angle will be very difficult to do.
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Last edited by pelanj; 11th January 2020 at 08:23 PM.
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