++Yes, all speakers contribute "murkiness" compared to headphones. Partly this is due to there being an enclosure, and partly to sound from the rear of the drive unit emerging from the enclosure also. Audiophiles speak highly of (mostly DIY) speakers which either have a front only and no sides or back. Or are mounted flush in a brick wall so the rear sound disperses harmlessly somewhere else. Arguable a loudspeaker box is the worst possible solution (even a horn is better in theory ).
The other problem is that it is impossible to make a high quality drive unit which covers all frequencies, so it is usual to have at least separate units for the treble and the bass/midrange. To cut costs these are usually all driven by one amplifier (on each channel). This has the effect that the drive units are not only driving the amplifier (back EMF) but driving each other as well. The result is further murkiness to the sound, with loss of dynamic accuracy on both transients and low-level sonic detail.
It is advised to look for (a) active speakers in which each drive unit has its own dedicated amplifier (usually built into the box), (b) evidence of engineering consideration of the problems associated with speaker enclosures - this could be irregular shape, or special materials, or type of construction. Of lesser importance are the quoted average power rating and the maximum sound pressure levels, as most equipment in the "public address" category is designed to reproduce levels greater than that of a piano.
It is not recommended to use the home hi-fi unless it is known to be able to handle high levels, due to the risk of destroying the high frequency drive units from overload distortion.