Audio levels in HDMI variable?

[Davidk]

I have a laptop that in class, is attached to an HDMI wall screen, via an HDMI cable. It runs win 7, and several versions of VS are installed. The sound drivers are configured so that when HDMI is attached, it is the default audio connection, and when it's not the laptop speakers are used. Thus a vsp played on the laptop is shown on the wall for students to see/hear.

I have a situation where an (audio commentary) sound in a vsp sounds a normal level when using the laptop speakers, but when connected to the HDMI screen, is almost in-audible. Turning the level up in the laptop made some difference - but mostly I actually had to get into the vsp and adjust the levels for each commentary clip to 2x (200 relative). Taking that vsp back to the main editing desktop - PC speakers only - the adjusted sound levels were almost too loud and reducing them needed. In short the original sound level in the vsp commentary clips was OK. And that made me wonder about sound over an HDMI connection.

Ordinarily, this has not seemed to be a problem - I play student smart packaged vsp's over that HDMI connection every week. But this is the first time any reduction in sound level been particularly notable. Is there something in HDMI that produces a softer level of sound over the connection? is there a way to adjust for that?

[weaver]

Check in the monitor (TV) setup the audio settings. In many modern TVs there is an automatic level control, to correct the sound levels between different sources. Maybe this tries to modify the sound level. In HDMI there is no level adjustmets as it uses just the audio-video-subtitle streams and forwards it 1:1 into the monitor input ( one of the signal sources)
The problem may be in stream ( i have similar issue, when I normalize the audio channel on the computer speaker it is distorted on extrenal monitor ( played from HDD, not from PC) the sound is OK. On the same computer the normalisation in Audicity or other sound processing SW works fine.