Lots of bass at walls, lack of bass in center of room/listening position

...so in a smaller room you cannot get good bass without subs ?

Yes you can but you have to work harder at achieving the goal. Your room width is the same as mine and about 3 feet less in length than mine so I know it can be done. To start, get at least one if not both subs out of the corner. A couple folks posted links to videos that show you how to place subs using the crawl method. Try it out, you might be surprised. I use the method referenced by Atmasphere, but you can accomplish this with 2 subs as well, and they don't have to be big subs.

Most speakers don't provide that 'room lock' bass in my room that I hear in shop demos. I can't explain why but I had a pair of speakers on stands I couldn't get any bass from so due to the insanity of this hobby I flipped the stands over, mounted them to the ceiling than mounted the speakers to that and GOT the best bass ever! Why when the speakers were the same distance off the floor as they were off the ceiling and the same distance from the corners did it make such a huge difference? IDK, but it was embarrassing when visitors would bump their heads on them walking by. lol.
Often the best sounding systems by dealers have the speakers in the most unconventional places and if you don't have the freedom to place them where they sound best you're stuck with bass traps and digital eq along with your sub(s).  Nice speakers, seriously wanted to give them a try.

Thanks guys. Interesting anecdote about the speaker flip thing, heh.
Anyway I did some measurements. Both with subs, no subs and at my listening position and at a position that is 3 feet back and 3 feet from the left wall.
www.diabolicaldesign.net/Measure.jpg
Please have a look

See the null ~ 120 Hz ?  Makes me wonder if your speaker/sub polarity is not backwards.  Flip and re-run. 

Miller so in a smaller room you cannot get good bass without subs ?

Correct. And small means small relative to wavelength. Since the the wavelengths of the lowest bass we want are 40 to 50 feet or more (depends how low you want to go) then small is anything less than that. Which means pretty much every room in every house is small. 

Look, its pure physics. Even at much shorter wavelengths we have to be clever with speaker placement and use things like diffusers and absorbers to get a nice smooth response. Exactly the same is true of bass, only the methods used have to be physically bigger on account of the physically longer wave lengths involved. 

Notice when you go to a concert in a large dome or hall the bass is wonderfully deep and uniform no matter where you go in the hall. That's because these spaces are large even relative to low bass waves. The waves have room to run and so when they do reflect off the walls its in different directions and times relative to the wave. 

In a normal room, say 20 ft, the leading edge of the wave bounces off the floor, ceiling, and all four walls even before one complete cycle! The darn thing is coming back and canceling itself sometimes right at the woofer! Think about it. 

But the flip side is if you take all this into account and do it right then you can actually have really fantastic bass even in a small room. You just have to abandon the old false paradigm of one or two subs and embrace the physical realities of long waves and use lots of subs. 

Because there's lots of subs they don't have to be big and powerful. Four or five ten inch subs is way better than one 20" even if the one is ten times as powerful. Because the one will create one powerful set of room modes. Bass will be thunderous but only at certain locations and frequencies. You will fight and struggle to tame this lumpy boomy awful bass. Which will not even go that low, by the way. But the four small subs will create four times as many different modes, each much smaller, so the bass will be smooth, powerful, and go really deep. 

DBA subs don't even have to match. Mine are a combination of three different subs. The bass is to die for.  https://systems.audiogon.com/systems/8367