Yes, somewhere there will be, but you haven't given enough information for us to know where to look. XF86AudioRaiseVolume is a keysym: depending on what distro you're using, a file somewhere (like .Xmodmap) will be attaching it to the appropriate keycode for your keyboard (i.e. one that corresponds to a "volume up" button or something). This in itself does nothing other than presenting the XF86AudioRaiseVolume symbol to your software whenever you press that button.
Somewhere else (and this will depend on your distro, what window manager or desktop environment you're using, etc.) a process will be sitting in the background monitoring keypresses and responding to them. On my (XFCE) desktop, the window manager (xfwm4) does this job, so there's a "keyboard preferences" option within which a "shortcuts" tab allows me to attach specific actions or programs to keypresses. So, if I wanted XF86AudioRaiseVolume to bump up the master volume by 5%, I'd attach it to the following command:
aumix -v +5
and that would do the trick. Basically you need to find where your desktop environment is handling the XF86AudioRaiseVolume keypress event and tweak that setting (from -v +10 to -v +5 if it's using aumix). Without knowing any more about your particular setup, all I can suggest is going:
grep -R XF86AudioRaiseVolume .[!.]*
to search all the configuration folders under your home directory for files that mention that keysym. If you're lucky you'll hit a file you can edit that way, even if you're not sure where to look for the setting in your GUI menus.