I have a 5.1 set of systems, and just bought a 7.1 receiver. My fronts have always been way more powerful than the center and rears. Now, I'm wondering if I should invest in a couple more speakers to round out to 7.1 ... AND I'm looking for advice on the best approach to balancing my existing speakers. Aren't their devices out there that help with that?
Jeff, you pose two really great questions. Both of which can greatly increase your enjoyment of home audio. I'll address each seperately...
#1. "Rounding out" to 7.1 is a question that is mostly dictated by your room, not as a balancing act between front and rear power, which is addressed by question #2. Adding more rears is not to make rear effect volume more powerful, but to enhance the surround effect of content. If you'll receive no additional enhancement by adding more speakers, than there is no need to do so. Check out this article: "Determining the Best Speaker Configuration for a Surround Sound System" and post any follow up questions here or in the discussion page for the article.
#2. Anytime you have speakers that are more powerful than others indicates a problem with sound pressure levels, or to put it simply, a problem with each channel's individual volume level. Balancing your system is probably the most important thing you can do to better enhance your surround experience with the equipment you already own. If your center seems weak, all you'd need to do is match that speakers volume output with that of your fronts and rears for a balanced effect. The tool to do this is called an SPL meter, and your receiver should have the necessary tone to work with it. There's a detailed article here at TechLore with detailed instructions about balancing audio, and using an SPL meter. Read this article: "How To Calibrate Your Surround Sytem Using an SPL Meter" and post your follow up questions here or in the article's discussion page.
Jeff if you use the SPL meter make sure you put the meter in the middle of the normal listening area. Which if you are trying to balance a 3 channel stereo image (LCR) The best listening position is half the distance between the L and R which should also be equal the the distance between L C and R C
Is the new 7.1 reciever in your family room where your 5.1 was? If so then I don't think you would see much by going to 7.1 considering all the new set of channels would be doing is outputing a delayed image of the rears you already have.