Listen to sound effects: Good sound quality is characterized by clear sound quality and full music sound. You can try playing different types of music to see how well the speakers handle different types of music.
Bass effect: A good waterproof Bluetooth speaker can play bass powerfully, rhythmically and without distortion, and the bass effect is full without being blurry.
Frequency response: A good Bluetooth speaker should be able to provide balanced sound quality across the entire frequency range, including bass, midrange, and treble.
Dynamic range: A good Bluetooth speaker can maintain the stability of the sound quality when adjusting the volume, without obvious sound quality attenuation or distortion.
User reviews and professional reviews: You can refer to other user reviews or professional reviews to understand the sound quality performance, advantages and disadvantages of this Bluetooth speaker.
The best way is to try out different Bluetooth speakers in person, compare their sound quality performance through comprehensive considerations, and choose the one that suits you.