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Multi-Way Conventional loudspeakers with crossovers

Dual opposing 2.5 speaker?
Dual opposing 2.5 speaker?
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Old 18th September 2018, 08:36 AM   #11
rabbitz is offline rabbitz  Australia
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There was nothing special about the project but I've added a pic for reference. As you can see they were too close to the wall and needed to be 1.25m into the room to work properly but I couldn't afford that distance. The 0.5 woofer was crossed over at 125Hz. The 0.5 woofer was in line with the front woofer.

The closer to room boundaries the less BSC you require and you can't control that with a 0.5 woofer as you get full BSC unless you attenuate the signal going to it. Place it in the corner and the effect will be worse as you will get massive gain at the bottom end and suck out higher up the range at around 0.3 x the wavelength to the boundary. See the attached Fig 1-3 which shows the variation with 1 boundary and compare to that shown with 3 boundaries. You only way you can overcome that is to have the drivers at least 1.25m into the room where the effects will occur well below 100Hz (ref Roy F. Allison).

You may not need the 0.5 woofer and the best advise is to have every dimension from the woofer to a boundary to be as different to one another as possible and not be a direct multiple as well. This will place the reflections at widely different frequencies and smooth out the low frequency output.

It's been said, "more bass is not necessarily better bass".
Attached Images
File Type: jpg RZ6_2004.jpg (41.8 KB, 55 views)
File Type: jpg Boundary effect.jpg (311.6 KB, 56 views)
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Last edited by rabbitz; 18th September 2018 at 08:42 AM.
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Old 19th September 2018, 12:11 PM   #12
Drummer 35 is offline Drummer 35  Spain
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Rabbitz,

Did you used a first order xover for the 0.5 woofer? IŽll need a huge coil if using 2nd order and crossing that low.

I think IŽll discard the rear woofer option due to room placement problems. canŽt put the speakers far from the walls, so I think IŽll follow your advice and the graph you attached.

Thanks for your help
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Old 20th September 2018, 02:11 AM   #13
rabbitz is offline rabbitz  Australia
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It was first order and IIRC a 5.6mH inductor for the 850122. On later builds I added a CR zobel to roll off the woofer faster.
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