オンド・マルトノ
In addition, the development of electronic amplifiers for musical instruments now enabled quieter instruments such as the guitar and the string bass to compete on equal terms with the naturally louder wind and horn instruments, and musicians and composers also began to experiment with entirely new electronic musical instruments such as the Theremin, the Ondes Martenot, the electronic organ, and the Hammond Novachord, the world's first analogue polyphonic synthesiser.