5. Now we enter another element of 5.1 sound called DRC (Dynamic Range Controller) which is a fancy name for a limiter or compressor where low sounds are perceived louder and high level sounds are made softer. In most cases the use of such devices will make the over all sound softer and some devices offer a gain make up of which VLC does not and the DRC is on by default for both ac3 and DTS in VLC. Try shutting off the DRC and listen again. The sound will be more natural and clearer and a bit louder by approximately 1.5 to 3 dB depending on the source.
Hey there DJ, sorry it took so long to reply, I started to mess with this issue again when VLC 0.8.6b was released. Here are my findings so far:
When Audio output module "default" is selected, boosting the volume level over 100% works fine with 5.1 and 2.0 video files and also the volume level is fine. Now to get 5.1 truly working with S/PDIF I must select Audio output module "win32 waveout extension output". After this 5.1 video files (with audio device a/52 selected) volume level is the same when trying to change volume level in VLC, I have read that with S/PDIF truely enable you can only change volume with amp? So everything seems to be OK with 5.1 material.
But when "win32 waveout extension output" is selected and Iam watching 2.0 material, the sound levels are way below what Iam getting with "default" audio output module so I have to crank my amp volume really high to get some volume out. Also going over 100% volume level does not seem to be working when "win32 waveout extension output" enabled, because volume level 100% is as loud as 200%. With "default" audio output module the volume levels are generally much higher than with "win32" and also boosting volume over 100% works.
Anyways I can live with changing the Audio output module from "default" to "win32 waveoutput method" depending on whether Iam watching 2.0 or 5.1 videos. Just wondered if this is how its supposed to work
Also found what seems to be a bug. VLC crashes everytime when I enable settings/extended GUI/equalizer/and tic then enable (preamp) button. This happens with 5.1 video using "win32 waveout extension output" and while a/52 audio device is selected.
ps. I reread DJ your posting and I must say, thanks for the very informative post. I have always wondered why 5.1 Dolby material sounded so much quieter than other formats
