As recounted in this article, some of AMRAD's initial vacuum-tube transmitter work involved testing ideas on improving the transmitter's modulation. And while testing the work at AMRAD's experimental station, 1XE, impromptu phonograph record programs were broadcast, for anyone to hear, including passing ships.

Electrical Review and Western Electrician, April 16, 1916, page 672:

Wireless  Achievements  at  Tufts  College  in  Massachusetts.
Experimental room
    The transmission of music by wireless with a small amount of power, giving a range of more than 100 miles, so that ships at sea have picked up tunes, has been brought about at the station of the American Radio & Research Corporation, at Tufts College, Mass., of which Harold J. Power is general manager. The mere fact of sending music to the distance mentioned is not in itself a remarkable feat, but by means of a novel method of introducing the sounds in the radiated waves, resulting in articulation and loudness in the waves received, a marked gain has been achieved.
    To provide the high-frequency current necessary Professor Power employed an oscillion bulb, the invention of Lee De Forest, of New York. Machine Shop
    It is recognized that there are two important factors in the successful transmission of wireless telephone messages. One is the generating of high-frequency currents and the other its modulation in accordance with the voice or the music to be transmitted. It is the latter of these two problems that Professor Power is especially interested in, because the De Forest oscillion is recognized as a perfect means of generating the needed high-frequency current. It has been possible for some time to obtain sufficient power to transmit telephone messages to any distance, but how to introduce the voice at high-power stations in a practical manner, is the great problem of radio telephony, and to this branch of work Professor Power is now devoting much attention. His device for introducing the voice is far from perfected as yet, but successful results have been obtained, from reports thus far received.
    Operators at several stations on Cape Cod have reported recording the strains of well known popular airs produced by a phonograph, and in two instances steamers entering Boston reported picking up the music more than 100 miles out from port.
    The radio station's equipment is one of the most complete in the country. Students in Tufts College have the facilities at their disposal for experimental work, though the plant is owned by a private corporation. A number of valuable results have been developed by members of the Tufts Wireless Club.