Question about 3 way crossover connection

[LuisNiels]

hello everyone, i have a pair of yamahas NS-555AV and a pair of technics SB-2865... both 3way speaker system. and i was checking the crossover connection and i found out that on both yamahas and technics the positive lead of the mid range is connected to the common negative of the woofer and twitter on the crossover... that seem odd to me.. the connection is factory.. but i was under the impression that all negative leads must be together... is this type of connection common?? anyone knows something about this? i'll include a diagram of how they are connected, check the positive lead of the mid.. thanks everyone (forgive my bad english)

 

[mhardy6647]

some order crossovers invert polarity.
http://www.apicsllc.com/apics/Misc/filter2.html

first order = 90 degree phase shift
second order = 180 degree phase shift (reverse polarity will 'align' it)
third order = 270 degree phase shift
...

 

[shelly_d]

It is very common. The crossovers cause phase shifts in the signal. The midrage is at the end of 2 filters, not one, so the phase shift can be considerably more then either the woofer or tweeter. To put the music that the speaker produces back into closer phase the midrange is often wired up in reverse. Keep the wiring as it is.

Shelly_D

 

[LuisNiels]

mhardy6647 and Shelly_D i didn't know that.. thank you very much, for clearing that up for me, i will leave wiring as it is