This paper addresses a placement planning method for drones to improve the performance of source tracking by multiple drones equipped with microphone arrays. By equipping the drone with a microphone array, the drone will be able to locate the person in need of rescue, and by deploying multiple drones, the 3D location of the sound source can be estimated. However, effective drone placement for sound source tracking has not been well explored. Therefore, this paper proposes a new drone placement planning method to improve the performance of sound source tracking. By placing multiple drones close to the sound source with multiple angles, it is expected that tracking will be performed with small variance. The placement planning algorithm is also extended to be applicable to multiple sound sources. Through numerical simulations, it is confirmed that the proposed method reduces the sound source tracking error. In conclusion, the contribution of this research is to extend the field of drone audition to active drone audition that allows drones to move by themselves to achieve better tracking results.