How to set the volume of mp3 file in decibel type?

Question

I play a noise and a sound at the same time. I need to increase or decrease the noise in decibels. I have to calculate the SNR value. In a web project, can I output sound in the right decibel when the user's computer is turned all the way up? Please help me set the sound in decibels of the code snippet below.

var a1 = new Audio(`https://www.learningcontainer.com/wp-content/uploads/2020/02/Kalimba.mp3`);
a1.volume= 0.2;
a1.play();