Here's a strange situation. My STB is connected to the 990 with both component and HDMI/DVI connections. Audio is coax. The 990 is connected to the TV with both component and DVI/HDMI connections, with no separate audio. (I have an independent cable connection directly to the TV with the standard cable coax.)

When I have the TV source set to receive the HDMI input and the 990 set to send the HDMI output (via the DVI out) I get a fine picture and sound coming from the 990's amplifier connection. The strange thing is that I also get sound coming from the TV! I know this because when I mute the 990, there is sound coming from the TV's speakers.

There is no separate audio connection between the 990 and the TV. This suggests that the HDMI signal from the STB that has both a video and audio component is being passed to the TV through the 990, even though the physical connection in and out of the 990 is DVI. I thought that the DVI connection didn't pass the audio, but apparently it does. At least I can't think of any other explanation for the sound coming out of the TV's speakers.

Am I missing something? Did I misunderstand what happens with the HDMI signal? Can anyone explain what's going on?

The 990's DVI switching is a pure pass-through, and is fully capable of switching both audio and video from HDMI sources. This means that when you switch an HDMI source to an HDMI display using the DVI switching, the HDMI audio will reach the display. EDIT: I went back to my review notes, and while it was made clear at that time that HDMI's "blacker than black" data survived, nothing specific was said about HDMI's audio data. What you are experiencing suggests that the pins in HDMI used for audio may be passed through the DVI switching, but we've never had it confirmed either way.

"... The 990 is connected to the TV with both component and DVI/HDMI connections, with no separate audio. (I have an independent cable connection directly to the TV with the standard cable coax.)" Is the independent cable you talk about a analog audio cable from cable box/DVR out? I have my oppo hookup to both DVI & component in of 990 and audio to 990 through coaxial and 5.1, when watching DVD I still hear the directv sound from my TV because there is a set of audio cable from my directv analog out to the audio in of a component channel of TV, lower the TV volume or take the analog cable set away eliminate the TV sound.

No, the "independent" cable is really that, a coax from the wall to the TV's "ant in" jack. I have my Oppo hooked up the same way that you do, but there is no audio connection directly from the STB to the TV. I think Gonk probably got it right suggesting that the the full HDMI A/V signal is being passed through the 990 even though the connectors are DVI. Can the Outlaws comment on this?