Head unit compatibilty with active sub.

[TbM]

you will still need to hook up both L/R RCA's to be in bridge mode. or else only half of the signal/ output voltage power will be experienced. - I.E 5V preout will be half to 2.5V.

I would like to know how its halving the voltage?
The Hu in question only has 1 output so If it were say 5v output for example, splittling it only give you 5v on each split, doesnt double the voltage, weather the amp is recieving one 5v line or a split its still recieveing the same voltage.