Three major problems persisted, leading to motion pictures and sound recording largely taking separate paths for a generation. The primary issue was synchronization: pictures and sound were recorded and played back by separate devices, which were difficult to start and maintain in tandem. Sufficient playback volume was also hard to achieve. While motion picture projectors soon allowed film to be shown to large theater audiences, audio technology before the development of electric amplification could not project satisfactorily to fill large spaces. Finally, there was the challenge of recording fidelity. The primitive systems of the era produced sound of very low quality unless the performers were stationed directly in front of the cumbersome recording devices (acoustical horns, for the most part), imposing severe limits on the sort of films that could be created with live-recorded sound.