Windows 7 - HDMI playback, system sounds nearly inaudible

Argh. I can usually fix whatever isn't working, but this has proven to be a match for me and I'm hoping that someone here has some idea what might be going on.

I just set up a new mobo and monitor: Intel Socket 775 (to use some old parts) DG43GT and an Asus VE248Q. They're connected by a known-good HDMI cable. There's no problem with video and (this is where it gets interesting) no problem with audio using WMP or other playback applications. There are no other known problems in the setup. The monitor has notebook-sized speakers, so I've set the highpass filter in the monitor device properties for 200Hz. The resulting audio is loud enough and listenable, for what it is. However, the system sounds are nearly inaudible and don't seem to "play" properly either when system-initiated or when using the test button on the sounds dialog. Sometimes they'll play from the beginning of the .WAV, sometimes it sounds like the start of the .WAV is cut off. It's not the mixer because that's set for 100% level on system sounds as well as 100% on WMP etc. All adjustable levels, including the monitor, are set at 100%, which ends up being a bit too loud for WMP, but not nearly loud enough for the system sounds. Other playback devices are disabled, so there's no chance of interference. Finally, as an experiment, I loaded all of c:\windows\media into WMP and all the WAVs and MIDs play just fine. So that pretty much points the finger at the system sound "player", and that's where I'm stuck.

Forgot to mention: "communication" is set to "do nothing" when phone calls are detected.

Any ideas?

Finally got to the bottom of this. The "explanation", which unfortunately isn't a "solution" may be helpful to others.

The problem isn't in Windows. It's in the monitor. Specifically in the HDMI digital audio section of the monitor.

When the (analog) audio from the PC is connected to the analog audio input on the monitor, there's no problem. However when HDMI digital audio is used, there's some delay time from the onset of the audio event to the time that the monitor actually produces audio. IOW, there's a start-up time associated with digital audio that's not present with analog audio.

Since Windows audio events are intermittent and infrequent, the monitor essentially "squelches" the first ~1 second of the audio event. Therefore some Windows sounds never sound at all, while the tail end of some of the longer ones can be heard.

Aside from playing audio constantly so the monitor audio system is always active, I don't see any fix for this.

The monitor, BTW, is an ASUS VE248Q. I have a feeling that other ASUS monitors in this family will behave similarly since they're all on a common hardware platform.