Micro gas turbine engines are a popular subject in research activities. Most of them consider performance measurements, and vibration analysis that are related to operating running engines. Operating even small-size engines causes potential risk to operator health. The research problem was to identify the acoustic flow field from the front and back of the operating GTM-120 engine. The research was divided into three parts: identify noise at various rotational speeds, identify an acoustic field of the engine, and identify noise level at additional points. Obtained results identify that noise from such a small engine at the range of 67 to 109 dbC is harmful and unpleasant to people who are within a radius of 15 meters from the engine. The final conclusion is that installing mufflers for any size of turbomachinery should be mandatory.