Having recently learnt a bit about surround sound in the realm of TV and film, I've been considering what kind of application it could have in other areas of audio entertainment. Coming from a mostly musical background, I can see a huge benefit in having multiple speakers to mix on rather than the typical stereo, left and right pair. Seeing as most consumer speaker systems are stereo, mixing a song in 5.1 or 7.1 seems almost like a fruitless venture, but there are benefits to "upmixing" (maybe we'll leave that for another blog). Truth be told, a lot of the surround mixing I've seen for in music has been for live concerts and such. So with such a focus on surround sound in visual mediums, it got me wondering how it's utilised in video games, and if it's even relevant in a consumer market.
There are a lot of topics in this blog that can be (and should be) investigated further, and I will possibly do so in following blogs. However, I will try and keep this discussion around the relevance of surround sound in video games for this blog.
What is surround sound?
First off lets take a quick look at exactly what surround sound is. A typical surround set up consists of 5 speakers and a subwoofer (5.1) or in some instances, 7 speakers and a sub (7.1). Some typical examples of these are illustrated below.
These kinds of setups are commonly used in surround sound mixing suites, cinemas, and even home theatres on the consumer level. Mixing to a surround sound setup gives you the opportunity to use multiple sound sources for your audio for either immersive ambience in film or clever instrument and sound placement in music. But not everybody has the kind of money or even the need to have a set up like this at home, especially at your computer desk, so how are people able to experience surround sound in video games without the need for multiple speakers or an expensive setup.
Surround Sound in Headphones
There are two ways headphones manufacturers achieve surround sound, one is a configuration of speakers in each ear to simulate a 5.1 or 7.1 setup, and the other is virtual surround.
True Surround
True surround sound in headphones is achieved using multiple drivers ("speakers") in each ear, simulating a traditional 5.1 or 7.1 speaker system. Unlike normal surround sound configurations, gaming headsets that utilise surround sound also offer an above and below perspective, as well as a 360 degree soundscape. Razor's Tiamat 7.1 V2 uses 5 drivers in each ear. The different positions of sound is emulated by increasing and decreasing volume in each of the drivers to simulate the position of sound in the video game, with one large diaphragm speaker in the centre offering bass response.
A set of these bad boys would set you back roughly $250AUD, which is pretty steep for a pair of gaming headphones but considerably cheaper than even an entry level Yamaha 5.1 surround sound home theatre system, which could cost around $400.
Virtual Surround
If you're not willing to fork out hundreds of dollars for a decent pair of surround sound headphones, you can take the cheaper route of virtual surround sound. This kind of surround sound is simulated with the use of only 2 drivers, one in each ear. "The auricle of a person's ear has lots of surfaces that can reflect sound waves. Most of these surfaces are curved. Some might direct the sound toward other surfaces in the ear, causing the wave to bounce more than once before reaching the tympanic membrane" (Wilson, T, V. 2007). Virtual surround takes advantage of this by applying aural cues to the sound wave, fooling your brain into interpreting the sound as though it came from five sources instead of two (Wilson, T, V. 2007). This is also achieved with single speaker systems for home surround sound using a similar process that reflects sound from the walls of your room. Headphones that produce virtual surround sound can purchased for anywhere from $40 to $100, so it's definitely the cheaper option.
Physically using separate speakers to achieve surround sound is obviously going to produce a much more convincing effect as opposed to using only two speakers and virtual surround. I personally have a pair of headphones that have a Dolby virtual surround sound feature which to my ears produces a very "tinny" reflective sound that can be disorientating to say the least.
Surround Sound Utilised in Video Games
Generally when you're playing a video game that involves a 3D space, you'll experience certain sounds from different perspectives regardless of the speaker system or headphones you're using. In most typical consumer scenarios, this is experienced in a stereo (left and right) spectrum, so it's not hard to deduce that in order for a game engine to suggest the location of something emitting sound is by increasing and decreasing volume in either speaker depending on how close an object is and what direction the sound is coming from. There are a few parameters to cover when localising a sound in a video game and it all depends on whether the sound source is; above, below, behind, in front, far away or close to the player. These sorts of mechanics are important mostly in first person shooters so that the player can determine the location of their enemies, which becomes even more important when a game involves stealth tactics. Soundsnap does a good job of explaining the varying factors of directional sound in this list;
Distance: The further away, the less volume the sound has. But the spectrum of the sound also changes. A sound in the distance has less energy in it’s high and low frequencies. This is a realistic indicator that something is very far away. Battlefield games achieve this well in their large open maps, letting distant gunshots sound like minor pops.
Direction: While the simplest of localization concepts, directionality is the most important in first-person games. Directionality in games has evolved from simple stereo to surround sound, and recently more evolved surround sound with headphones, using something called a head-related transfer function (HRTF), which replicates the way the human head perceives sound. This gives full directionality including above and below a player.
Acoustics: Every room sounds a bit different based on its size, geometry, and contents. The way something sounds from another room can be a mental cue for players.
Occlusion: When there is a wall in between you and a series of gunshots, depending on the size and thickness of the wall, the gunshots should sound more or less muted. Objects that occlude sound give the world more dimension and informs the player.
Masking: A great (an often unthought of) factor is the masking of softer sounds by much louder sounds (think A Quiet Place when they went to the waterfall). The more your player relies on sound, the more it matters when it’s interrupted.
All of this is calculated through whatever game engine a developer might be using, or by implementing a third party application such as F-Mod or Wwise. It seems as though basic directional sound can be achieved without having to incorporate a stereo set up, with the exception of a couple of things like the aforementioned HRTF which is really only useful if you're using headphones and plays back into the realm of digital surround sound. This also means that it will be hard to determine the location of a sound source if it is behind you for example, for this you would most definitely need either surround sound headphones, at least a 5.1 speaker system or be using digital surround with headphones. So do game developers have to incorporate surround sound into their games or does any game work with surround? It turns out that unless a game has been specifically built with the option to switch to surround sound, a majority of games will simply work with PCM (Pulse Code Modulation) which is "The primary way analog audio signals are converted into digital form by taking samples of the waveforms from 8 to 192 thousand times per second (8 to 192 kHz) and recording each sample as a digital number from 8 to 24 bits long" (PC Mag), and works in stereo only. You can however convert your PCM signal into 5.1 using DTS or Dolby Digital Live by using a Digital Audio Decoder which you can pick up for anywhere from $30 - $100 depending on quality. So effectively, you can convert any audio signal from your computer to your 5.1 set up and turn it into 5.1 or 7.1, which almost completely eliminates the need for developers to incorporate surround sound mixing into their games, unless of course they have done so purposely with Dolby technology.
In Summary
Surround sound can definitely enhance your gaming experience by offering a wider directional range of sound, but in order for you to experience this, you either need to get yourself a pair of fancy headphones and put up with having to wear them every time you play, or invest in a costly and slightly higher maintenance 5.1 surround sound system. As for implementing surround sound into video games on the developers end, it almost seems like pointless extra work due to the fact that your game will almost definitely already incorporate the directional sound needed for immersive game play, which can be converted into surround sound by either the headphones being used or a DTS or Dolby Digital Live audio converter for those that have surround sound systems. Some games like Doom (2016) have the option for your game to play using Dolby 5.1, eliminating the need for a converter, and presumably (I don't have a surround system so I can't test it myself) incorporating surround sound more delicately and purposefully into the game.
If you can put the money up for a decent surround sound set up then there are many ways you can experience your favourite games in 5.1, but from a developer stand point, implementing surround sound directly into your game is, 1, presumably very costly (Dolby software doesn't go cheap) and 2, rather unnecessary due to the standard audio systems of the consumer today.
Bib
Surround Sound Gaming Headset - Razer Tiamat 7.1 V2. Retrieved from https://www.razer.com/gaming-audio/razer-tiamat-71-v2
Crider, M. (2017). What’s the Difference Between Virtual and “True” Surround Sound Gaming Headsets?. Retrieved from https://www.howtogeek.com/295722/whats-the-difference-between-virtual-and-true-surround-sound-gaming-headsets/
Tucker, B. (2017). 7.1 Surround Sound Speaker Placement | 5.1 Surround Speaker Placement. Retrieved from https://www.octaneseating.com/surround-sound-speaker-placement
Wilson, T. (2007). How Virtual Surround Sound Works. Retrieved from https://electronics.howstuffworks.com/virtual-surround-sound3.html
5 Ways to Use Sound as a Core Video Game Mechanic - Soundsnap Blog. (2018). Retrieved from https://blog.soundsnap.com/2018/07/24/5-ways-to-use-sound-as-a-core-game-mechanic/
PCM Definition from PC Magazine Encyclopedia. Retrieved from https://www.pcmag.com/encyclopedia/term/49008/pcm