I'm a newbie to the HTIB world. Our home is pre-wired for surround sound so I purchased the Onkyo HTS 5100B HTIB. I didn't realize until I got home that the HTIB includes 7 speakers but we only have 5 prewired connections. I researched Onkyo's 5 speaker system and it does not have HDMI inputs like the 7-speaker. I'm trying to decide if I should return the 7-speaker and switch to another brand or just use 5 of the 7.