My Kids Watch speaker wheezes at high volume

Kids Watches of the KW51 series (models "Polly" Kids Watch CNE-KW51BB, CNE-KW51RR, CNE-KW51BL) have a high degree of protection against moisture ingress IP68 (full protection), which allows these watches to be immersed in fresh water to a depth of 1.5 meters for up to 30 minutes. To provide such a degree of protection, the sound speaker of the watch is covered with a waterproof protective membrane, which conducts sound well, but at high volume levels it can begin to vibrate, which is perceived as wheezing. This is not a design defect, but only a design feature. To get rid of wheezing, try lowering the signal volume (it is possible only during the calling and conversation) using the green volume buttons (“+” and “-” in the right part of your GSM Watch screen) as shown in the illustration below: + increases the sound volume, - decreases the sound volume.