Ok, you have convinced me that a good subwoofer (like the Shiva) can play 80hz signal with no problems at all. My next question is: If I only use one sub, which is located between the front speakers, and want to use my mains as "small", what will be the highest frequency that I can set the crossover and still enjoy a large and spacious soundstage ? I have read in many places, that when using the fronts as "small", in some systems the soundstage becomes much narrower. What is the frequency at which we REALLY start to not localize the sound ?. I made a test and played a tone signal at 80hz, one time through the left speaker, and the other through the right. I was able to easily localize the signals. This mean that 80hz signals still contain localization cues which our ears can detect, which mean that when playing movies/music we will lose these localization cues and make the soundstage narrower if sending them to a sub. If I want to retain large soundstage, will I have to use two subs ?. I know I can always set the sub's crossover at 35hz, but then I will suffer from huge room modes, since my main speakers are not EQ'ed for flat frequency response like the sub will be (and my room modes are between 40-70hz).