Full range speakers with no adjustment for bass loudness in a small room will not work no matter if the bass drivers are 3-7" or 1-15". The reason subs with monitors are suggested for small rooms is you can independly adjust bass output for the room.
There are some full range speakers that do allow adjustment of the bass level but these are basically just built in subs. My speakers have this feature and it makes them much more flexible.
The farther the individual speakers are apart on the baffle the farther away you need to sit from the speaker for the sound to integrate. You need to sit at least 9 to 12 ft away from most 3 or 4 way speakers for the sound to integrate well. Then you also need space behind the speaker or bass will be boomy among other problems.
Regarding B&W 803 vs 804 the 803's don't really put out that much more bass than the 804's. I used to have 805's with a sub many years ago. I have only heard the 803's at the dealer in a large room. That said I think you could get away with the 803's in your room. Just don't try and stuff 802's or bigger in there. The 803's would benefit from a good sub as well IMO. As far as I know they only go down to mid 30 hz. Unless their specs have gotten better over the years.
The fact that the drivers on the B&W speakers are close together on the baffle should help them integrate better in your room.
Sean
There are some full range speakers that do allow adjustment of the bass level but these are basically just built in subs. My speakers have this feature and it makes them much more flexible.
The farther the individual speakers are apart on the baffle the farther away you need to sit from the speaker for the sound to integrate. You need to sit at least 9 to 12 ft away from most 3 or 4 way speakers for the sound to integrate well. Then you also need space behind the speaker or bass will be boomy among other problems.
Regarding B&W 803 vs 804 the 803's don't really put out that much more bass than the 804's. I used to have 805's with a sub many years ago. I have only heard the 803's at the dealer in a large room. That said I think you could get away with the 803's in your room. Just don't try and stuff 802's or bigger in there. The 803's would benefit from a good sub as well IMO. As far as I know they only go down to mid 30 hz. Unless their specs have gotten better over the years.
The fact that the drivers on the B&W speakers are close together on the baffle should help them integrate better in your room.
Sean