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Multi-Way Conventional loudspeakers with crossovers

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Old 9th March 2007, 04:57 AM   #41
Apogee is offline Apogee  United States
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Interesting project.

I'm curious how they sound with no toe-in?

45 degrees seems to be fairly extreme. How do they image when setup with no or very little toe-in?

Also, how far apart are your speakers and how far back is the listening area?

Thanks!
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Old 9th March 2007, 09:25 PM   #42
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The toe-in is critical to how they work. It focuses the bulk of the total acoustic output into the room and minimizes room reflections. The high dispersion provides for uniform frequency response to about 90 degree off axis. The directionality of the tweeter above 8 khz coupled with the 45 degree toe-in results in an elliptical energy/sound isoform ( a very wide sweetspot) such that when one is closer to one speaker, the high frequency output of the opposite speaker is greater as the latter is being heard more on axis vis-a-vis the speaker that is physically closer. The result is a very broad sweetspot and an extraordinary sense of presence and soundstage. If the speakers are no toed in, the result is an extremely oversize soundstage at the expense of image localization.
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Old 17th March 2007, 10:49 PM   #43
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Hi mamboni,

I have been following this thread with the intention of making a speaker like this. I would prefer the tweeter to be at ear height of 36" and that would require me to make a shorter sonotube base unit. If I follow your math correctly I figure a tube 28 inch H x 14 inch dia. should get me near your 2.5 cu. ft. target. I like your selection of mid-bass speaker and have been looking for a project that used them. I'm also interested in the "Walsh" traveling wave concept and want to see just what will happen. To complement the "open" radiation pattern of the Walsh I want to try a dipole tweeter such as a B&G Neo 8 or a Heil tweeter and cross over at 3.6 Khz with a 12 db slope - still driving the bass full range as you suggest. I would love to see any drawings or construction photo's you may have - as well any feedback.

Thanks,
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Old 18th March 2007, 04:52 AM   #44
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I humbly admonish you to exploit the Walsh principles at work - to utilize the much higher crossover point afforded by the driver as implemented in my design. The great advantage of the bending wave principle is the ability to reproduce virtually the entire audible bandwidth without the phase and time distorting crossover filter. With the 10" driver as illustrated in prior posts, excellent results have been obtained using a simple first order high pass filter (a capacitor) to the tweeter at 8-10 khz. The effortless and correct midrange that results from this alignment, wherein a 10" woofer lends it's copious radiating surface for the reproduction of the midrange up to the hihest partials of the strings and voices, must be heard to be appreciated. Also, any quality tweeter you choose will enjoy exceptional power handling and freedom from intermodulation distortion afforded by the high crossover frequency, one far above what is possible with conventional 2-way or 3-way designs.
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Old 18th March 2007, 04:57 AM   #45
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The design provides for time alignment of tweeter and woofer. The woofer is run full range to about 8-10 khz, where rolloff occurs secondary to voice coil inductance and mass. The tweeter uses a simple high pass filter, a capacitor and resistor in series:
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Old 18th March 2007, 05:00 AM   #46
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The woofer cone must be treated with felt damping to provide for proper wave termination and thus control cone breakup modes above 2 khz:
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Old 18th March 2007, 05:04 AM   #47
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Roger on the high x-over - I will comply with your recommendation. What are your thoughts on using a 28 inch high by 14 inch dia. tube?

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Old 18th March 2007, 06:42 PM   #48
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Those dimensions for the tube will work fine. As this is a sealed enclosure (acoustic suspension), the volume could be increased 10-20% to obtain a lower Q and somewhat lower Fc. Also, you might want to incorporate a variovent to extend bass response and improve impulse response. This approach has been used quite effectively by Dynaudio systems.
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Old 18th March 2007, 07:23 PM   #49
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Default Electrohome Walsh idea satellite speakers

I found a pair of vintage Electrohome satellite speakers on chains designed to hang friom the ceiling. I`m guessing 60`s vintage. Inside they have a bending wave transducer with an all paper cone. These don`t go low but they sound pretty amazing.

3 pictures to follow....
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Old 18th March 2007, 07:25 PM   #50
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View of the insides. The driver is about 5 inch diameter.
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