A customer has a Fender/Sunn 4 x 10 and it's wired in series parallel... no surprise there.

The thing that caught my interest is that the cabinet is wired with two series pair of speakers connected in parallel. I have always used 2 parallel pairs wired in series, you get the same resultant total impedance with both but the 2 series pair version of this wiring presents much different and more extreme results when there's a problem and one speaker goes out.

For example: if you have 4 ohm speakers each at 50 watts then the normal working series parallel wiring would result in a cabinet with 4 ohms impedance and 200 watts of power handling capacity ideally. If the cabinet is wired with the 2 series pair in parallel, the loss of 1 speaker will take out it's pair speaker as well resulting in two speakers going silent. The wattage will go down to 100 watts and the impedance will raise to 8 ohms. If you have the cabinet wired in 2 parallel pair in series, if 1 speaker goes out only that speaker will go silent, the wattage will drop to 150 watts and the impedance will rise to 6 ohms.

This makes me wonder why anyone would want to wire a quad in series parallel with 2 series pairs in parallel? Does anyone have any thoughts on this. I know when I scan the web I see both circuits recommended but I also know that stuff on the web is often "monkey see/monkey do" and a deeper understanding of the circuit analysis is almost always missing.

The thing that caught my interest is that the cabinet is wired with two series pair of speakers connected in parallel. I have always used 2 parallel pairs wired in series, you get the same resultant total impedance with both but the 2 series pair version of this wiring presents much different and more extreme results when there's a problem and one speaker goes out.

For example: if you have 4 ohm speakers each at 50 watts then the normal working series parallel wiring would result in a cabinet with 4 ohms impedance and 200 watts of power handling capacity ideally. If the cabinet is wired with the 2 series pair in parallel, the loss of 1 speaker will take out it's pair speaker as well resulting in two speakers going silent. The wattage will go down to 100 watts and the impedance will raise to 8 ohms. If you have the cabinet wired in 2 parallel pair in series, if 1 speaker goes out only that speaker will go silent, the wattage will drop to 150 watts and the impedance will rise to 6 ohms.

This makes me wonder why anyone would want to wire a quad in series parallel with 2 series pairs in parallel? Does anyone have any thoughts on this. I know when I scan the web I see both circuits recommended but I also know that stuff on the web is often "monkey see/monkey do" and a deeper understanding of the circuit analysis is almost always missing.

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