Thank you for supporting Xiaomi products. The slight noise or distortion you’re hearing at maximum volume could be due to the quality or characteristics of the audio source itself. Short or low-quality audio files, such as those with low bitrate or heavy compression, can not sound as clear when played at high volume, which could cause some distortion.
Another reason could be that the device's speakers, while high-quality, are designed to provide clear sound at a wide range of volumes. However, at maximum volume, the speakers will push the limits of their output, leading to slight distortion or noise.
You can try lowering the volume slightly to see if it alleviates the issue. The Xiaomi 15 has undergone rigorous professional inspection to ensure that its external sound volume meets high-quality standards, and the built-in speaker system is optimized for clear, immersive sound.