Ah! You've discovered a conundrum that we had to deal with early in our development of the Windows version. The issue has to do with how Windows handles hardware volume controls, especially on laptops. Here is what happens:
1) The volume controls on a laptop or those specifically built into a keyboard will usually control the default audio device.
2) When DPS boots it automatically detects the current default playback device and remembers it.
3) DPS then switches the default playback device to the Digital Power Station driver so all audio is routed to DPS.
4) Then DPS sets it's output to the default hardware device it remembered at startup.
5) If the users has changed output devices while on a certain category (Built-In, Desktop, Headphones) it remembers this as well so that output is always associated with the appropriate category.
The issue happens when the laptop user has their volume set to 50% or some other lower number when they launch DPS. When DPS switches the default driver to Digital Power Station the volume controls on the laptop or keyboard now only control the output of DPS. Can you see the issue here? The laptop will now only go to 50% volume even when it is turned all the way up! The user would have to manually go into the volume control on the Task Bar (or Sound Settings in XP) to turn up the output driver for the hardware. Yuck!
So this was our compromise to provide "it just works" functionality; for the Built-In and Desktop categories we automatically set the hardware output driver to 100% before switching to the Digital Power Station driver. For the Headphones category we leave the volume where it is for the reason you discovered... we don't want to blast anyone's ears! You will notice that if the last time you ran DPS was in Headphones mode, when you launch DPS there should be no big jump in gain. Also, a device driver becomes the "Communications device" if it was the last one selected as a default output. It is really just a label though. Some applications such as Windows Messenger or Skype may pay attention to this label but if you are using DPS, then you should set the output device in Skype to Digital Power Station.
It took us a while to fully understand the quirks of the Windows audio system! Since there are so many third party drivers interacting in there no one system is ever the same. If you have a better idea for how to implement the volume control issue by all means let me know! The only criteria is that we don't want to add more controls for this. It should be automatic.
