My room has "zero" slap echo. Do I need room treatments?

Thanks for your responses.  To clarify about my room... the horizontal log walls are flat on the inside except for a 1" miter cut at the top and bottom ( so there is about 6" of flat surface and a 2" groove).  If you bang the side of your fist against the wall all you get is a sore fist.  It's really dead sounding.  However, I have seen some log home systems with rounded logs on the inside that would help diffusion and some "post and beam" that were rounded on the vertical.  So, what would work best behind my speakers?

Forgot that you asked about the bass.  I just added two JL Audio E112's to the room and it is incredible what they have done to my whole system's SQ.  As I said above I have a large and very irregular room and needed these subs to pressurize the room to get better sound.  Very happy with the bass.

Using a test tone or more than one test tone and SPL meter you can map out the sound pressure zones in any room. Standing waves, first reflection points and pressure build up in room corners tend to be where the highest sound pressures are measured, sometimes 6 dB or higher than the average sound pressure in the room. Those are where there the treatments should go, generally speaking. Speaker location should be optimized simultaneous. 

Thanks, I do have the Stereophile test CD's and an SPL meter so I will do my best.  

Yes you need Stillpoint Apertures at least 4 they will improve any room.