Architectural guidelines and standards for classroom acoustics are needed for the general population, as well as for special groupings such as hearing- and learning-disabled students, non-native listeners and talkers, and teachers with mild-to-severe hearing handicaps. Without specific guidelines, economic considerations or ignorance may tempt architects and school boards to use ``standard commercial practices'' for classroom construction such as ``Noise Criteria'' (NC) classifications. Proposed NC-40 ratings are unacceptable for many people in special groupings. An NC-40 classroom is sub-optimum for serious learning situations, even for the general population of children and adults. Needed acoustical guidelines can ensure adequately low noise and reverberation so that the speech-to-noise ratio and speech-to-reverberation ratio allow satisfactory communication and learning. Acoustical guidelines are also needed in connection with the growing use of classroom amplification to ensure that amplified speech is not used inappropriately, such as in reverberation-limited conditions or where inadequate sound isolation between adjacent classrooms produces distracting crosstalk. Guidelines can be developed with the cooperation of acousticians, architects, audiologists, school building officials, and government. Some of the costs for higher acoustical standards will be returned indirectly. Quiet classrooms may be a good investment for America.