Even if the perfect room were to exist (see Acoustics), it would still be impossible to perfectly recreate the energy from a sound source through any sort of sound system.

In the process of designing (or choosing) a room and a sound system, it's important to consider both the acoustics of the space and the content of the intended program.  While a good sound system (run by a good technician) may be able to compensate for some of the difficulties of running sound in a poor acoustic space, addressing the problems inherent with the physical acoustics of the room will yield a better sound quality than attempting to fix them with a more expensive system.

Sometimes, the sound system is limited by the physical characteristics of the space.  In a given room, certain frequencies may resonate particularly well, creating a natural feedback sort-of effect.  Depending on the positioning of speakers (and the resonant characteristics of a room), certain positions in the room may be more prone to feedback (where a transducer will essentially hear itself as it sound comes out of the speakers).

Each transducer (i.e. microphone, pickup, or speaker) introduced into a system will have certain characteristics based on the materials used to create it.  Some may be physically unable to respond to certain ranges of sound; some are intentionally designed to add or remove certain resonances as they transduce the energy.

Also, each electrical component of a system will have its own characteristics and limitations: amplifiers are designed to multiply the amplitude of an electrical signal by a certain ratio range, but won't be able to exceed those ratios; some electrical components will (intentionally or unintentionally) add certain types of resonance to the electrical signal.