Absolutely Yes, you get superior sound. You can do this on my REL Q108 sub bass system, they provide both cords, and encourage you to wire it this way (while saying that if only one connection is used to wire directly from speakers). I did hear a difference, a much braoder sound. Try it and see, you will be surprised. REL claims you get the most out of your sub bass this way. Without using the plug from your preamp, they claim you miss out on many HT effects.