wiring parallel or series sensitivity rules?

It should be obvious that +6dBspl summation of two coherent sources can only occur for all frequencies only along an arc in space, that arc being defined by where the propagation delay from each source is equal. For more than two sources the arc of +6dBspl is reduced to a single point in space, and then only if all of the sources are positioned on the circumference of a circle so they are all equidistant to the summation point.
A correction to my post above: For two sources there is a number of arcs, which form a plane of equidistance to the source where the sum is coherent for all frequencies. Where more than two sources sum coherently, there is a series of points, which form a line in space.
 
Reading back through this old thread, there may have been some confusion that seeped in along the way. The attached graphic is to get us all on the same page.

j.
 

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What if we have 3 identical drivers at 4ohms each..? If i say wire 2 in series and the last parallel. Have 3 laying here, testing now to measure impedance and same time listen and can clearly hear differences,

The one in parallel (single driver) will produce same spl at 1W as the other 2 in series. Right? Atleast the single one plays louder to my ears compared to the other 2 hooked up at the same time.
If i serie connect all they i get around 12-13ohm. Parallel about 1-1.2ohm.
Also tried wiring 2 in paralell (2ohm) and then series with 1x 4 ohm and i get a 3 valleys/dips instead of usual 2 in this ported box im testing it in. Any thoughts about that or how to best wire this for freq under 200-300hz? Just curious if i can get this 3 woofers in same cab to play together without having to low imp load or too high.
 
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Running a ported box with 3 drivers with uneven contributions is an interesting proposition. As it turns out there's probably not a lot of compelling reason to do it.

I guess if you had a choice you'd like to get the impedance closer to 8 ohms. Using the three in series and using an amp with more Voltage would be one option. Putting the three in parallel with an amp with more current is the other.

Unless you plan to build such an amp I'd probably prefer to put them in series and use a higher powered amp so it can supply the Voltage without difficulty.
 
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