How far can room treatments solve boomy bass?

If you ask 10 people if a PARC is the key, i guess you get opinions that differ. YES, it is in the signal path all the time.
You can use a Bypass button to shut it off if you like to do so with older, less dynamic and bass heavy recordings.
The PARC is only an EQ, it is not an instrument that helps you read/measure the room.
For this, i suggest you buy XTZ - Room analyzer pro II.
http://www.xtz.se/uk/products/measurement-system/room-analyzer-ii-proT
It is probably among the cheaper of all these kits and many acoustical companies use this prog and some dealers of Rives Audio also use it as it is cheaper than BARE (Rives own kit).
ALL is included, just plug it in and run the sequence. You will find it easy to use. If you buy this kit you can do alot of measurements (from 15hz and beyond) or you can set it up as instructions say and you get data you can start off with and you can also leave it like "this". "This" data you get, is the frequency or frequencies + the Q-value and the level (+db) the mode/modes. When you have the data of both channels (you can measure both separately and set both channels independant), you just type them into the PARC.
You deduct the db peaks of the mode(s). You need not set it at flat (linear), if you don't wish to. You can fine tune the setting after what you like if you do not wish to use flat.
But, if you use for example Gic acoustic devices along with PARC, you can void flutter echo and "bass mumble". The more panels you use, the more damped it will be. Some may not like this, some do. That is why i suggest you use both XTZ RA pro II and Gik acoustics devices. The Room analyzer pro II is not at all much more expensive than the original Room analyzer, but it is delivered with a better microphone and has more features. With Gik devices and PARC, you can set up your system almost in any room and find a very good set up that you like. If you buy the most advanced acoustical devices, and the heavy large bass absorbers from ex.

http://www.performanceacousticslabs.com/PAL/Products-Acoustics_Listening_Rooms.html

Look at Varitune V6 and V4.
You'll notice these are large and heavy. They work, they really do, but you might need 2 or 4 or 6 or 8 units.
All pending on how much db and how many modes you'll need to rid (lower in db).
An EQ is a good choice due to the fact that it will help you get a less boomy sound without a need to use these bass absorbers.
The EQ does not boost, just deduct level. Not everything is for every one, but the benefits are surely larger than those on the negative side.
What you will notice, is that it is a larger difference in dynamics at your recordings. Not all people like near flat (linear) response. The PARC will only rid the mode(s).
The devices from for instance Gik, will help you tune the room byond modes. But as mentioned, for the most crude bass modes you will need the PARC.
When you have (if you will buy these things) all done, you probably will notice a significant change in the whole range you hear. Then you can start looking over cables, tweaks and/ or repositioning your speakers etc. This kit will make the soundfield more precise less prone to let the room interact as much.
What is so nice with for example Giks 242, 244 and Tritraps is that they are light in weight. The PARC is small and not heavy. It is not as filling the whole room with heavy bass absorbers and diffusors all over. Using only acoustical devices, is not always so easy to use everywhere (due to size, weight and wives, girlfriends).
This kit that i use, helps me to set up my system in both a small room and a large room.
I can listen to all sorts of music and i can change settings if i want to. I believe in my head and heart, if you could hear this for yourself and cope with what a full kit would do, you would find more benefits to it all and it makes sense.
I play loud, very loud at times. I have been through lots of equiptment way more cosly than my current system. But this gives an illusion of doing all genres without issues and at times it's like using headphones. Just much more exciting if you get what i mean. Ofcourse you can ask and ask again if you want. I understand if some things might be of consideration. After all, it took my years to get it through that this is the best way for me. I hope i am not to unclear!?

Real simple...small speakers are for small rooms...get some monitors for the moment until you refigure your current situation....I feel your pain...I have had sets of floorstanders over the years...and was never satisfied with the bass...boomy and slow....probably the case of too much speaker in a given room...or placement issues....

River251, for bass below 200hz try checking out the Cathedral Sound Panels. They are not absorption panels but instead work on the venturi principle which says that a gas moving through a small opening will speed up which in turn is related to pressure changes in the room from the woofers. To the drivers the room becomes effectively larger, acoustically. The frequency range of the panels is optimized by the size of the holes in the 11"x16"x2" panels that you install in the upper room corners. They control standing waves without rolling off the highs and are about 90 bucks each. I have not used them (I currently have the opposite problem you do, my 13.5'x15.5'x8' livingroom is largely open to the rest of the house), but I've heard others say that these panaels are the only type of passive room treatment that they use. Worth a look.

My experience tends to match what Phasecorrect wrote.

Monitors are perhaps a safer move. Assuming that people seems to go through acoustics half hearted. The risk with fullrange speakers (most often floor standers) is always that bass modes will be unavoidable and it cost some to get the bass modes an the rest under control.
Looking through some threads, also talking to acoustics that work this every day, has made me understand. None of the audio-bugged i have visited has done what is needed to make the environment nearly as good as the rest of the system.
Another bizarre thing here is cable dealers, who claims this can be solved with different cables. I guess a graph can tell each and everyone how much bass modes and dips can affect the whole frequency range. Basically, the room (environment) is as important as the system.