Will a subwoofer add depth and clarity to my system, or just bass?

I would add a pair of REL T/9i's.  I listened to the Focal Aria line and I kept asking myself where is the bass.  I also asked myself if audiophiles do not like bass in general.  Even their largest 948 aria speaker lacked in bass extension.  Adding two T/9i's will really help.  

I continue to be amazed by the knowledge of this group.

i wonder why the group does not talk about master setting speakers.  One of our local dealers demonstrated the art of master set.  He demonstrated this in one of his listening room.  When he moved the right speaker 2 feet, we suddenly had to raise our voices to hear each other.  I also noticed how I suddenly began to hear right and right speakers.  The sound also was not relaxing.

This dealer is one of the largest REL dealers in the country.  During his demo he donstrated adding a REL S3 to a pair of   Vienna Acoustic Mozart’s and I had a difficult time hearing a difference when adding the sub.  I wonder if this was because the Mozart can get down to 24 Hz.  Have really good ears and wonder why I couldn’t hear the difference.  I was expecting to really hear the bass beat.  I do think I heard greater in the mid range.  I purchased a pair of Paradigm Prestige 85F’s and now feel they sound harsh in the mid voicing.  The dealer came to my home and told me they needed to be master set. He also suggested adding a pair of REL T/9i’s.  He told me this would clear up the mid’s And make them sound less harsh.  Based on this discussion this must make sense.  However, before buying the REL’s I wish I could hear the difference in sound.  The dealer told me REL’s are not designed to pound out the bass and if they were they would eventually drive me out of the room.  So far, I am saving up to buy the REL’s.

I listened to a pair of SALK Song3 Encore’s at the RMAF and had I listened to them before buying my Paradigm’s would have never purchased my Paradigm’s.  I certainly would not need to add a sub other than for home theater.

You have all lost me.  Guess I need to get a sound engineering degree to understand.  Wonder how you all learned this?