You mostlikely know this ...when you set you receiver to big the full frequency gets sent to the mains. Whatever setting you have on your sub will play at its own crossover point. So if you set your man to large and your speaker rolls off at 27Hz and you have your sub set to roll off at 80 hz. You would have both your sub and mains playing the same frequency between 80-27 Hz. Gving a nice full sound. If you had it all that time and switched to small you receiver would send all the frequencies below 80hz (thats if you set it at that) to the sub exclusively. It would definitely sound less fuller because your sub will be playing all frequencies below 80 and your mains will not. (not considering the roll-off of the mains) It is a preference between every individual. Some set it to large some set it to small. Definitely setting it to large for HT gives a nice ummmppphhhhh!!!!
