Present electrical sound equipment has little output below about 100 cycles. An electrical device of large output in the range 30 to 200 cycles would afford new musical effects not hitherto possible.From a review of existing literature it is concluded that an acoustic output of at least one watt should be provided. Ten watts would be desirable. The result can be attained in several ways and the amount of equipment required with various arrangements is calculated. The results should serve as a guide in the design of installations.