What makes a speaker too big for a given room?

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

Since it seems that many people are a bit confused about this topic, I hope you guys do not mind if I sum up the good responses posted so far and also add some of my own believes and experience on the discussed topics.

Large speakers in small room problems:

1) Amount of bass. Large speakers (with large drivers) can easily overpower a small rooms by producing too much bass. Since most speakers do not allow one to adjust the amount of bass, tuning the bass output of a speaker for a given room can be extremely difficult (often impossible).

2) Speaker placement. Speaker placement in a room is crucial not only for stereo image and sound stage but also spectra balance. Placing a large speaker into a small room will limit considerably the ability to move the speaker around in order to minimize the speaker-room interaction, e.g. reflection, resonances.

3) Integration of the drivers. Large speakers with many drivers require one to sit farther away from them for perfect integration. Depending on the situation this may be impossible to achieve with large speakers in a small room.

Floor-standers vs. monitors + subwoofer

1) Volume level. Except for very expensive models, most floor-standers need to be cracked up quite a bit in order to get decent bass out of them. Often this is needed also in order to get the midrange to open up. Thus, IMO many floor-standers do not performed well at low volume levels. On the other hand, monitors excel here.

2) Speaker-room interaction. Monitors interact less with a room as they have a) smaller and more rigid cabinet walls, b) it is easier to place them in a room in such a way to minimize reflections, c) do not produce that much bass. Further, having the ability to move the bass source (the subwoofer) around the room is another huge advantage as almost always the speaker position that yields the best midrange integration and spectra balance differs from the position that yields the best bass integration in a room. Furthermore, most modern subwoofers provide additional adjustments, e.g. parametric equalizer, phase, crossover point, etc, that further aids the integration of the speaker system in the room.

3) Quality of low bass. Most decent subwoofer will have much more accurate and healthy bass than most good and very good floor-standers.

4) Mid-bass. Many argue here that most decent floor-standers get this region right while even expensive monitor - subwoofer combinations fail to do so.

Best wishes,
Paul

Wow thats a tough on DUDE!!

FWIW, I have a pair of Dali Helicon 400's in a smallish room, and they sound quite nice at low and mid-volume levels! I have a CJ PV-15 pre-amp feeding into a JWN tube amp, which has 8 el34 output tubes. Lance Cochrane estimate it at around 100 watts per channel. The amp itself has a higher sensitivity than my old solid state CJ AMP, and it controls the bass better as well. I get an incredible soundstage with lots of three dimensional detail. Something about the ribbon tweeters in the speakers makes them sound almost like panels in the mids and the highs, which are to die for.

I have the speakers around 7 feet apart, and I sit about 10 feet back.

Poor design. For if the loudspeaker is large but designed to integrate and work in smaller spaces it can. Its many of the smaller designs that are compromised and under sized for proper sound quality. And may require near-field use in small rooms due to extensive Thermo and dynamic compression. Most Subwoofer designs again are compromised in design and one ends up with a large excursion driver in overly small cabinets thus requiring massive power and floor or corner boundary reinforcement to produce lower frequencies. And again Thermo compression rears its head as large power is forced into voice coil. Reducing efficiency, dynamics, transients and adding distortion.