How to set the loudness of HTML5 audio?

Question

In an HTML5 game I'm making, I play a "thud" sound when things collide. However, it is a bit unrealistic. No matter the velocity of the objects, they will always make the same, relatively loud "thud" sound. What I'd like to do is to have that sound's loudness depend on velocity, but how do I do that? I only know how to play a sound.

playSound = function(id)
{
    sounds[id].play();
}

sounds is an array full of new Audio("url")'s.

Answer 1

Use the audio element's volume property. From W3:

The element's effective media volume is volume, interpreted relative to the range 0.0 to 1.0, with 0.0 being silent, and 1.0 being the loudest setting, values in between increasing in loudness. The range need not be linear. The loudest setting may be lower than the system's loudest possible setting; for example the user could have set a maximum volume.

Ex: sounds[id].volume=.5;