Hey Everyone,
Last night I did some re-wiring work on my Ashton 4X12 Quad Box, basically re-wiring the speakers from it's stock wiring to what's called a series-parallel wiring where I have two 8 Ohm speakers wired in series which are then connected in parallel with another two 8 Ohm speakers that are wired in series, the original stock wiring of the speakers was two 8 Ohm speakers wired in parallel which were connected in series with another two 8 Ohm speakers which were connected in parallel, this is what I call parallel-series wiring, here's a diagram to illustrate the differences between the two methods of wiring-up the speakers, note that both methods result in the same total impedance of 8 Ohms.
Here's why we end-up with a total impedance of 8 Ohms for each of the two wiring methods, in the case of the stock Parallel-Series method of wiring, if we wire two 8 Ohm speakers in parallel we get a total of 4 Ohms, if we wire 4 Ohms in series with another 4 Ohms we get a total of 8 Ohms because the two 4 Ohm speaker loads add-together.
On the other hand, if we wire two 8 Ohm speaker loads in series we get a total of 16 Ohms (they add together), if we then wire two 16 Ohm speaker loads in parallel we get a total of 8 Ohms because two identical impedances in parallel will always result in a total impedance of half of one of the impedances.
Remember, resistances in series add, and if you put two identical resistances in parallel, the result is always half the resistance value of one of the resistances.
In the past, I have tried my Ashton Quad Box out with my Marshall amp by unplugging the internal speakers from the socket and plugging the Quad Box into the 8 Ohm speaker out, and I remember my Marshall amp sounding a bit weak and thin as well as low in volume, well, I noticed a dramatic difference when I tried the Quad Box out with my Marshall amp after I had re-wired it to a Series-Parallel configuration, the Marshall sounded much fatter, louder, and more dynamic too, all the speakers in the Quad Box measured fine on my multimeter, no coil rubbing either, I was really surprised at the difference, literally day and night, very happy with the results I got from the re-wiring.
Each of the four speakers are Celestion Rocket 50s which I presume are rated at 8 Ohms/50W each.