No way that I'm aware of. The audio is fed to the browser in an HTML <audio> tag. What the browser then does with it is beyond the skin's control. There is a volume attribute, but the default is 1.0, the highest available.
Remember, too, that the volume of the audio on a web page is controlled by the settings on the user's own PC or Mac. There's no way of knowing what's happening on the visitor's machine. When you view the album from a server, your browser may simply be remembering that the last time you hit a site with music, you turned down the volume.
What makes it particularly confusing is that there are three ways of altering the volume - there's the slider on the audio player in your browser, there's a volume control provided by your operating system, and there is often a physical volume knob on your speakers. None of these knows that the others are doing.
Thanks for the usual quick, thorough response. I vaguely remember asking this question a long time ago (obviously for Matrix) and I'm sure the answer then was the same as now. I'm aware of all the volume options outside the jAlbum/skin options, so when I send a link to the family of an album where the volume is important I always urge them to turn up the volume on their viewing device.