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steve1977, I am sure I'm not the most appropriate person to explain this, as I am not knowledgeable enough in audio technology. With my limited knowledge I can tell you I believe downmixing is the process by which an audio signal is converted from one number of channels to a lower number of channels. So if a video piece has a 6 channel audio track and you only have a 2 speaker setup (like I have), or a 2.1 channel setup, there has to be some...downmixing of those channels in order for the whole audio stream to fit on your 2 channels.
I think downmixing concerns people that don't have a 5.1 audio system. But I didn't say this whole issue is "caused" by downmixing; what I think is that if this issue is to be properly solved, something has to be done before the downmixing stage. If a channel is a lot louder than the others, its individual volume has to be adjusted before they are all mixed together. The problem seems to be that in XBMC the voice channel comes with a very very low volume. So if you want to hear the voices properly, you have to have every other sound at blasting levels. Also, there is no way to adjust the volume separately for each channel, so this doesn't affect only people who lack a 5.1 audio system. Movies have different volume levels for every channel so I believe a good solution for this would be to have volume sliders for each channel inside the XBMC settings. That way everybody can adjust volume accordingly without messing with the sound settings for their other applications. For people with 2.0 or 2.1 setups, the downmixing would be done with channels that are already adjusted.
I don't think there are just a few people who experience this. Perhaps people just got used to do remote control jockeying or to tinker with the driver controls or the hardware knobs trying to correct this issue from outside XBMC. Which is unfortunate, because more reporting of this issue would perhaps help developers aknowledge it and find a solution for it.
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sdburg
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I was always under the impression DTS sound tracks are designed to be extra loud on action scenes to give the viewer that cinema experience??
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I think the main issue here is this.
On a 5.1 source you have 6 channels.
Left Front
Right Front
Centre
Rear Left
Rear Right
Bass (.1)
What happens with down mixing is it takes Left, and Right and passes it through to the left channel and right channel at 100% volume. However with the main VOICE channel it seems to reduce the volume by 50% and send half to the left and half to the right; as some kind of rudimentary way of normalizing the audio. When in fact it should be taking the centre channel (normally voice/dialogue) and putting out at 100% on both sides.
Then in the moments of a film when you hit music/sound effects its blaring loud because these effects come through at DOUBLE the volume of the voice channel that you've probably adjusted your volume too.
Does this make sense to anyone else?
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It sort of makes sense. I see what you mean but I'm not sure that's what happens.
In my mind the mroe likely problem is that the effects are also rpesent in the rear left and right. That signal is also mixed in here, giving you "extra" audio information for the effects.
Now, I don't remember the math for this, been too long since I did take any audio related classes but this could result in a boost of volume for the effects, aka action sequences, in effect drowning out the center channel.
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