In conclusion, all that need be pointed out is that the system just described is one designed for the reproduction in auditory perspective of symphonic or other music to an audience. Because of its multichannel character and its wide range of frequency and energy capacity, it is not readily adaptable for use in small rooms. While theoretically susceptible of employing any set of transmission channels capable of handling the desired frequency and volume range, it is at least in the present state of the art restricted essentially to wire transmission systems. This restriction arises from three main sources: (1) The ability to free the system against extraneous electrical or noise disturbances which at times so frequently mar radio transmission. (2) The uniformity with which transmission characteristics can be maintained and the relative ease with which the effects of attenuation can be overcome by intermediate repeaters. (3) The fact that under existing statutory regulation of radio it is impossible to secure clear channels of a frequency band requisite for the complete transmission of all the fundamental and overtone frequencies produced throughout the full range of musical instruments and the human voice. Whether for local or distance use, the easily controlled and very tremendous volume ranges which the apparatus is capable of handling without distortion have placed in the hands of the musical director an implement for tonal effects not hitherto attainable. What the future use of the system in all its parts is likely to be will depend in large measure not only on the extent to which it is desirable to produce perfect music in auditory perspective at a distance remote from the source but likewise on the extent to which musical composers and directors find it effective in producing artistic effects beyond the capacity of the largest orchestras or choruses.