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Multi-Way Conventional loudspeakers with crossovers

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Old 4th February 2012, 06:55 AM   #11
seanny is offline seanny  United States
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Sounds like he wants to mount the mids under the dash and run the ducts into the waveguide above the dash.
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Old 16th May 2012, 07:26 PM   #12
Patrick Bateman is offline Patrick Bateman  United States
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Quote:
Originally Posted by weltersys View Post
Not to dissuade any experimentation, but when it is no problem to mount multiple drivers directly on the horn throat, what advantage do you see in remotely coupling them through a duct that severely limits the usable bandwidth, and does not attenuate out of band peaks as the throat coupling does?
The part of this puzzle that I didn't understand four months ago is that pathlength is very important with these devices.

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For instance, let's say you take the speaker above, and you replace that 10cm pipe with a hundred 1cm pipes. As I understood it a few months ago, the pipes of narrower diameter would pass high frequency energy better, since the wavelengths can form in the large pipe, but can't form in the small pipe.

The thing that I didn't understand then - which I understand now - is that pathlength doesn't care about wavelength. Even if the duct is so small that the wave can't form, the air molecules still need to exit in-phase.

But, again, the Paraline satisfies this goal nicely, because the sound radiates radially. When I first saw it, it seemed like such an odd device, because the sound is bent 180 degrees. But now that I understand the radial expansion, it makes sense.
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Old 7th February 2018, 12:19 AM   #13
Soldermizer is offline Soldermizer  United States
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Default Methods to damp the resonances?

Since the original goal of the tube is to deliver sound at a distance from the actual driver, we do not need to worry about the gain (?) that a quarter wave tube would have. On the other hand, can we damp the unwanted resonances? If so, would this not give much smoother frequency response? I have only read of this done for the mouth of a horn (this is distinct from the Geddes foam thing for HOM)... here is a link

Factors Affecting Sonic Quality of Mid & HF Horns & Waveguides

Sure enough, a round tube is a waveguide, and the question is would a "towel cowl" work for Patrick's idea?
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Old 7th February 2018, 01:43 AM   #14
nc535 is offline nc535
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are you getting mouth reflections from the end of your duct? try flaring it out at the end
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Old 9th February 2018, 01:15 AM   #15
Soldermizer is offline Soldermizer  United States
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I am just speculating, so I don't even have a duct right now Probably a flare would work, or any way to smooth the impedance. Of course, Patrick's original goal (to have a small midrange port where he wanted it) might be diluted if it has to have a Le Cleac'h flare and/or a turban looking surround upon it
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Old 9th February 2018, 01:03 PM   #16
Mrcloc is offline Mrcloc  South Africa
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Originally Posted by Patrick Bateman View Post
If light can travel hundreds of miles via a fiber optic cable, it should be possible to make sound travel have a meter over a duct.
This sounds so trivial, but it's not. Light in a fiber is very narrow-band. You get wider-band fibers (multimode), but they suffer more over long distances. Multimode also means more than one, not x to y wavelength. If you had to put a wide spectrum of light through a fiber, you would also see this peaking, and likely have absolutely nothing for many wavelengths.

Understanding Wavelengths In Fiber Optics

It might be worthwhile reading about wide-band transmission lines in electromagnetic theory. It's not a simple matter.
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Old 28th February 2018, 08:24 PM   #17
ErnieM is online now ErnieM  United States
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If I mounted a compression driver so it fires through a board then put another equal size board on top with a 3mm gap in between them, what comes out at the edges?
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Old 28th February 2018, 09:22 PM   #18
charlie2 is offline charlie2  England
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Originally Posted by ErnieM View Post
If I mounted a compression driver so it fires through a board then put another equal size board on top with a 3mm gap in between them, what comes out at the edges?
Fresh air

Dumb question how big is the board.......

Also what you are proposing wil load the driver at limited frequencies or a better perspective increase the drivers output
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Old 28th February 2018, 11:01 PM   #19
ErnieM is online now ErnieM  United States
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Maybe 21"x18". Basically want a similar effect to those omni directional Duevel speakers but with a much easier fabrication process.

Not too concerned with loading at the frequencies I would be using it at.

Last edited by ErnieM; 28th February 2018 at 11:03 PM.
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