kama.stein wrote:There's better ways to setup 5.1 so that it's better...
As far as positional sound is concerned, it's best to have speakers placed in a regular or semi-regular layout (that is, each quadrant or octant has speaker placements that are mirrors of adjacent quadrants or octants), or at least spaced evenly. Dolby's 5.1 layout doesn't adhere to that; it's designed to handle the needs and desires of film, which is different than real-time positional audio. With film, you can more precisely control where sounds can be and how they get mixed for an optimal response, and the viewer's focus is going to be toward the front 99% of the time. With games, you don't have that luxury. A sound can come from anywhere at any time, and it's important that the listener be able to localize it as best they can regardless of it's actual direction.
As for 5.1 being "front heavy" it has been argued that our hearing is more sensitive in the front.
That's true, but it doesn't make it any less problematic to deal with. It would be like if you had a monitor with a high DPI in the center that reduces as you go to the sides (human visual acuity is greater in the center compared to the edges), then being tasked with rendering and displaying a fixed DPI image in real-time with as little distortion as possible.
As Wendy Carlos has said on her site: "We're interested in an optimum plan or two for Human Surround Sound. Since the back of our heads is not nearly as sensitive to sound directionality and nuance (not to mention a poorer frequency response, and unfortunate interference as sounds move away from the rear of one ear towards the rear of the other), we ought not "waste" too much effort trying to obtain what we can't: a uniform sound field. That's where so many surround concepts fall down, assuming we humans can hear in 360 degrees and follow it all accurately."
She's talking about film and music, a non-interactive medium that can make sacrifices by knowing and designing the content ahead of time. But consider a game that has the player finding the location of a sound, either to reach it or avoid it. The player controls their character, so the sound's relative position to them at any given time is out of the control of the designer. And a person (in the real world) will instinctively turn their head in an attempt to more clearly localize it if they're trying to actively locate it, suddenly making what the designer thinks is the front and back of the soundfield no longer so.
Not wasting too much effort also doesn't mean to put little effort into it. In fact, it could actually require quite a bit of effort to reproduce a soundfield in such a non-uniform manner since you need to make sure any and all left over distortions are masked by the human auditory system's perceptual inaccuracy. In the long run it can be a desirable outcome as a way to save costs, but you need to be careful on how you get there. Adding audible distortions on top of the perceptual inaccuracy will make it sound worse.
Also, I gotta mention.. further setups with more channels (like ATMOS) tend to use the 5.1 layout as a bed and then they add on top of that.
OpenAL Soft handles each layout uniquely. Quad, 6.1, 7.1, and even 3D7.1 all have their own decoders designed for their particular layouts, regardless of any concessions 5.1 needs to make.
This is something that's less a problem with gzdoom since it doesn't tend to do a lot of in-game dialog (some mods might though) but having two different behaviors for sounds at 12 o'clock for in-game vs. cut scenes causes a jarring difference IMHO where the dialog would come from the center during full blown cut scenes but in in-game ones like in half-life they don't. There are games that use both (like the Mafia series).
It's less "different behaviors for sounds at 12 o'clock", and more different behaviors for a sound that happens to be at front (as with normal panned sounds) vs a sound that wants your clear and focused attention. Speaking characters are usually not centered (rule of thirds, etc), but their dialog still comes out the front-center speaker because it's close enough to what we expect and provides an unobstructed response that the viewer can clearly hear.
FWIW,
I'm not the only one that considers the front-center speaker this way:
No sound coming from Front Centre. - In some surround-sound speaker sets, the Front Centre speaker is a special "dialogue" speaker optimised for voice. Because of this, by default this speaker is only used for dialogue and not for general environmental sounds - so this is correct behaviour.
Some speaker manufacturers, and at least one other OpenAL vendor, see it the same way, the front-center speaker is designed for dialog rather than positional sounds. However, they default to excluding the front-center for positional sounds, while OpenAL Soft does include it (if at a reduced volume to maintain balance).
As I mentioned in the OpenAL Soft issue on this topic, there are improvements that can be made. In particular, I understand Dolby receivers include some kind of "steering" functionality to take a two-channel front stereo mix and pan the sounds in it between the front three speakers. Though I've found very little information regarding how that works, unfortunately, so it's something that needs to wait on the back burner until I can find something to go on.
SanyaWaffles wrote:The developer kind of all ready shot down this in a bug report Kama filed, so it's hard to expect help when we're kind of being told something different from the developer's perspective. I don't know the exact details but it seems the developer sees nothing wrong with the issues Kama described.
IMO at least, this kind of makes 3d spacializing of sound kind of useless, but that's just me.
On the contrary, what OpenAL Soft does is to help improve spatialized sound with 5.1. I also didn't "shoot down" this in the bug report; it's still an open issue, and I did say there is room to improve it. It's just not as easy to do as it may seem (
simple pair-wise mixing doesn't work for surround sound).
[quote="kama.stein"]There's better ways to setup 5.1 so that it's better...[/quote]
As far as positional sound is concerned, it's best to have speakers placed in a regular or semi-regular layout (that is, each quadrant or octant has speaker placements that are mirrors of adjacent quadrants or octants), or at least spaced evenly. Dolby's 5.1 layout doesn't adhere to that; it's designed to handle the needs and desires of film, which is different than real-time positional audio. With film, you can more precisely control where sounds can be and how they get mixed for an optimal response, and the viewer's focus is going to be toward the front 99% of the time. With games, you don't have that luxury. A sound can come from anywhere at any time, and it's important that the listener be able to localize it as best they can regardless of it's actual direction.
[quote]As for 5.1 being "front heavy" it has been argued that our hearing is more sensitive in the front.[/quote]
That's true, but it doesn't make it any less problematic to deal with. It would be like if you had a monitor with a high DPI in the center that reduces as you go to the sides (human visual acuity is greater in the center compared to the edges), then being tasked with rendering and displaying a fixed DPI image in real-time with as little distortion as possible.
[quote]As Wendy Carlos has said on her site: "We're interested in an optimum plan or two for Human Surround Sound. Since the back of our heads is not nearly as sensitive to sound directionality and nuance (not to mention a poorer frequency response, and unfortunate interference as sounds move away from the rear of one ear towards the rear of the other), we ought not "waste" too much effort trying to obtain what we can't: a uniform sound field. That's where so many surround concepts fall down, assuming we humans can hear in 360 degrees and follow it all accurately."[/quote]
She's talking about film and music, a non-interactive medium that can make sacrifices by knowing and designing the content ahead of time. But consider a game that has the player finding the location of a sound, either to reach it or avoid it. The player controls their character, so the sound's relative position to them at any given time is out of the control of the designer. And a person (in the real world) will instinctively turn their head in an attempt to more clearly localize it if they're trying to actively locate it, suddenly making what the designer thinks is the front and back of the soundfield no longer so.
Not wasting too much effort also doesn't mean to put little effort into it. In fact, it could actually require quite a bit of effort to reproduce a soundfield in such a non-uniform manner since you need to make sure any and all left over distortions are masked by the human auditory system's perceptual inaccuracy. In the long run it can be a desirable outcome as a way to save costs, but you need to be careful on how you get there. Adding audible distortions on top of the perceptual inaccuracy will make it sound worse.
[quote]Also, I gotta mention.. further setups with more channels (like ATMOS) tend to use the 5.1 layout as a bed and then they add on top of that.[/quote]
OpenAL Soft handles each layout uniquely. Quad, 6.1, 7.1, and even 3D7.1 all have their own decoders designed for their particular layouts, regardless of any concessions 5.1 needs to make.
[quote]This is something that's less a problem with gzdoom since it doesn't tend to do a lot of in-game dialog (some mods might though) but having two different behaviors for sounds at 12 o'clock for in-game vs. cut scenes causes a jarring difference IMHO where the dialog would come from the center during full blown cut scenes but in in-game ones like in half-life they don't. There are games that use both (like the Mafia series).[/quote]
It's less "different behaviors for sounds at 12 o'clock", and more different behaviors for a sound that happens to be at front (as with normal panned sounds) vs a sound that wants your clear and focused attention. Speaking characters are usually not centered (rule of thirds, etc), but their dialog still comes out the front-center speaker because it's close enough to what we expect and provides an unobstructed response that the viewer can clearly hear.
FWIW, [url=http://www.blueripplesound.com/openal-troubleshooting]I'm not the only one[/url] that considers the front-center speaker this way:
[i][b]No sound coming from Front Centre.[/b] - In some surround-sound speaker sets, the Front Centre speaker is a special "dialogue" speaker optimised for voice. Because of this, by default this speaker is only used for dialogue and not for general environmental sounds - so this is correct behaviour.[/i]
Some speaker manufacturers, and at least one other OpenAL vendor, see it the same way, the front-center speaker is designed for dialog rather than positional sounds. However, they default to excluding the front-center for positional sounds, while OpenAL Soft does include it (if at a reduced volume to maintain balance).
As I mentioned in the OpenAL Soft issue on this topic, there are improvements that can be made. In particular, I understand Dolby receivers include some kind of "steering" functionality to take a two-channel front stereo mix and pan the sounds in it between the front three speakers. Though I've found very little information regarding how that works, unfortunately, so it's something that needs to wait on the back burner until I can find something to go on.
[quote="SanyaWaffles"]The developer kind of all ready shot down this in a bug report Kama filed, so it's hard to expect help when we're kind of being told something different from the developer's perspective. I don't know the exact details but it seems the developer sees nothing wrong with the issues Kama described.
IMO at least, this kind of makes 3d spacializing of sound kind of useless, but that's just me.[/quote]
On the contrary, what OpenAL Soft does is to help improve spatialized sound with 5.1. I also didn't "shoot down" this in the bug report; it's still an open issue, and I did say there is room to improve it. It's just not as easy to do as it may seem ([url=http://members.tripod.com/martin_leese/Ambisonic/experiment.html]simple pair-wise mixing doesn't work for surround sound[/url]).