Why are big speakers in small rooms bad?

I'm moving shortly to a new house and a new dedicated room that is 11x15. I was hoping to use an old pair of PSB Goldi's that are, no doubt, a bit large for that size of a room.

My question is, what are the reasons behind big speakers being a no no in smaller rooms? I've heard that the bass will overpower the room. If so, then why are people recommending monitors with a sub for a small room? Is it simply because of more flexable placement?

So, if you're able to place your speakers anywhere in the room and apply suitable acoustic treatment to the room, what are the physics behind the universal disdain for large speakers in smaller rooms? Not tiny rooms mind you, but say a 150^2 ft. room vs. a 300^2 ft. room. All rooms have nodes and other problems, is it just easier to treat a large room?

Many large speakers need distance between the listener and the speakers for the speakers to properly integrate. When you set them up properly, usually well away from the back walls there isn't enuf room left to put the listening position in the right place. Of course that is only relevant if the best imaging is really important to you. Uneven bass response is a potential problem. A sub can sometimes work because you can position it away from the main speakers and take advantage of finding a locatation which provides the smoothest bass.
I suppose that the limited amount of drivers typically found in a monitor more easily integrate given the reduced listening distance.

I also suppose, that typically the greater bass quantities that larger speakers output may over power some rooms. Though you're exactly right, you can treat these problems pretty easily.

IMO, big speakers in little rooms arent necessarily bad. Look at my "small two channel" system. I am currently setting up what most would consider at least a medium sized speaker in an 11x11 room. I just started this system this week so no applicable knowledge is yet to be gleaned. Its currently breaking in.
The only way you will know for sure is to try the PSB's.

With the Goldi. As mentioned Bass response will probably be an issue. Another has to do with the speaker being a 3 way. You generally need a fairly large distance between speaker and listener for the 3 drivers to sound integrated properly when they reach the listener. These are basically the reasons a monitor or small 2 way floorstander are the speaker of choice for a small room.

BW Maxx
For me it is more a visual thing than sonic problems. My room is also small but I've had speakers as large as Vandersteen 2CE sigs in there and although the sound can get cogested at higher volumes, at normal listening levels they didn't sound too bad. They did however overpower the room visually. Give the PSBs a try and let us know how they work and what position works best.
11X15 Dedicated room doesnt sound all that small, you can pull your speakers 3 feet from wall and still have 10 feet of room between you and speakers if you place your spot on back wall (I gave you 2 feet from back wall) , if you place speakers closer to wall you have even more room.
So what I'm hearing is that driver integration for near field listening and flexability in speaker placement for flat bass response are the 2 most critical issues here setting aside most fixable acoustic space problems.

If point source driver integration is a primary concern in a small room, do full range planars and stats do particularly well?

I recently purchased CARA and will be modeling and playing with room designs. There are so many variables to work with that I didn't immediately consider; like driver dispersion and integration...

I originally asked PSB months ago about recommended room size for the Goldi's. They stated a value, if I recall correctly, of about ~220 ft^2. This seems almost silly to me, in light of the previous discussions, to suggest a room area rather than generic dimensions and listening distances. Or did they just tell me that as a quick and easy answer?

My thanks to everyone for their public and private replies.
I'll be sure to post the results once I get everything set up. I plan on spending a good amount of time modeling, tweaking, and measuring the room response. This is my first dedicated room and I'm very curious to see how well very different speakers can be integrated with the room when the significant other isn't a factor.

Thank you to all of you for your comments. I definitely feel better about giving the Goldi's a try now.
Distortion, I am very interested is the outcome of your Soliloquy experiment. I have an 11 X 21 room that is divided by columns that forces me to use the 11' wall for placement. I have the Soliloquy 5.0's, but have been debating on upgrading to the 5.3 or 6.2. Keep us posted!
Try the speakers first. I had a pair of Paradigm Studio 100s Version II in a 10 by 16 room. Sounded GREAT. The back of the speakers were about 8 inches from the wall. Seating position (back of chair)was about 2 feet from the opposite wall. Carpet over floor made of wood. Walls were typical plasterboard over 2x4s. Various stuff hanging on the walls.
Try them first.... At normal level, no problems. Cranked up, the treble would drive you out!! I had no problem with driver integration.
I have heard my PMC FB1s in a very small room and they sounded wonderful. These speakers are only 6" 2-ways but they are transmission loaded and rated to go well below 30hz. You will never know til you try them.
My room is 11 1/2 x 22. I used to have the Goldi's on the 11 ft wall and the bass was never enough for me.
Now I have a pair of PBN Montana XP's with seven drivers per speaker including 2 10 inch bass drivers per unit and I still find the sound to be very good and almost never too much bass.
You can't always listen to what many people say about these things. What doesn't work for some works well with others. The only way to find out for sure is to try it out yourself.
Try the speakers. All rooms should have bass traps anyway but a smaller room could easily need more of them. I've used very large speakers in my 12x17 room and have no problem. I sit 9 feet from my speakers and even with first order crossovers am having no issues. I like a big soundstage and large images. Also excellent bass is mandatory for me but use bass traps and will be using a digital parametric equalizer that just came out from AV123 to help tame the peaks that we ALL have until treated.
Cruz, I sure will. The speakers (Sol6.2) need a ton of break-in. As it is they have about 40 hours at the most. There is certainly a bass hump no matter where I place them. Patience is a virtue, so I'll dont plan on jumping the gun on bass control devices yet.

Super, I dont dont have any experience with Planars in small rooms. I see in the systems area that members Pcking and Ace427 both have Planars in small rooms. Maybe a direct email wouldnt be in order. I do recall a memeber building an all A'gon system on the cheap and commenting several times about the small room and how well it sounded. I am pretty sure he was using MMGs. So apparently some folks liked that arrangment.
Thats "would" be in order =)
I'm in similar situation. My room is 13x17x10.3, which, from reading around, is a small(ish) room (about 2200cf). I am currently using Studio 100 V1s that are probably too much for the room. The room is treated with Echo Busters products and some wall "hangings" and the 100s sound very good but I still have some significant bass "humps" that I've measured. It may or may not be the 100's fault, I'll know better when I get the Silverline Sonatinas I ordered. The best I've heard the 100's is currently 65" from back wall and 42" from the side walls. I sit about 7-8ft from the speakers leaving about 3-4 feet behind me. Closer to the front wall, the 100s were boomier and the soundstage shrunk.

Like others said, you need to listen for yourself and you will need room treatments (any room should have them if possible). You may want to get a SPL meter and some test tone discs. Part of my problem is the room is on the second floor and the floor is wood (rug covering). I'm thinking of trying some type stand to help isolate the speaker vibrations from the actual floor if my new speakers have the same size measured bass humps.
The speakers may or may not work in the room... you can only try it and see.

I have "big" speakers and they work ok in my room; although not perfectly.

A trick you might do is to try arranging the speakers diagonally.

This will gain you a little more room from the speaker plane (this worked wonders in my application - better soundstaging and improved bass).

Still need bass traps though... Of course YMMV.

Good Luck & Happy Listening!
standing waves...
Here in lies the problems with big full range speakers like the gold's in that room...First, placing the speakers where they yield the best response in the upper bass, will not be the case for the deepest base. Thus, often, you'll either be dealing with boomy unatural lower bass, or compromise the accuracy further up. Soundstage width must be balanced, and the seats (as the speakers), are going to need be out in the room, probably further than you'd like often. With seats placed properly out at about 1/3 of the rooms's length, you'll have to put the speakers out away from the sidewalls, and closer together, or you'll be boomy bellow 63hz reigion. So, soundstage width will be restricted full range.
If you do place the speakers on the long wall, you can help things often. but you should still consider 1/3 seating locations. Speakers would start at 1/6th from the front wall. If you have a solo-seat setup, speakers should be considered at 1/4 from sidewalls, if you sit in the middle of the room, yet staying 1/3 from front to back. These are good guidlines. But you still need to find where the speakers get best response overall. If you run the speakers as small, it helps your flexibilty, if you go "subwoofer".
Basically, if you run them full range for music, and don't cross over, the above mentioned will be your challenges, among others.
A possibly better option, if you chose to run the strong, dynamic, and deep sounding "Gold's" full range, is to "biamp" them! You can then get a good Parametric EQ on the bass woofers, without affecting the mid/high's! Otherwise, consider a good investment in the Rives Audio "PARC"...the best analog Parametric EQ ever made IMO.
Basiclally, your main challenge in a small room, is yes, the Bass response and setup. You'll have only a couple of options, as is. With EQ'ing you have more.
I could make the Gold's work in that small room, but it wouldn't be easy....