Robuta

https://www.tek.com/vn/video/how-to/50-ohms-output-impedance-on-function-generators
Arbitrary function generators (AFGs) are used to generate many different types of electrical waveforms, such as sine waves, square waves, triangular waves and...
output impedancefunction generatorsohmstektronix
https://www.dfrobot.com/forum/topic/374106
What is the specification of the speaker interface? What parameters of speaker are supported?
frequency rangeaudiooutputspecsimpedance