cam said:
You have a passive sub which is none powered. My experiences in the past, you had to route front left and right speaker wires to the sub and then to the front left and right speakers. Run your mains at LARGE, the filtering will be done by the passive sub. Full range from receiver to sub, sub uses 80 to 100hz and down or whatever it is designed for and then sends the rest of the frequencies to your mains.
OK, I am beginning to see the setup, I think.
If the main out goes to the sub then to the main speaker, the only way that sub will only get the lows if it has a crossover in it. Depending on the crossover frequency and roll of slope, if it is working properly, he should not be hearing anything above the crossover frequency.
The other side, the high pass side, goes to the main speaker.
Crossover should be 80 Hz or less.