I have a pair of bookshelf speakers that are connected to the subwoofer using the speaker level outputs of the subwoofer. The subwoofer has a crossover of 100 hz. The subwoofer is connected to the receiver using the speaker level outputs of the stereo receiver. I have a stereo receiver that does not have a subwoofer output and a subwoofer that does not have an LFE in or Line In. Questions: In this configuration, are the main speakers using the amp of the subwoofer or the receiver's amp ? Would I be able to achieve better sound if I connected the main speakers to the receivers speaker level outputs ?