Games and Music

11.   Feedback in Games and Music

Computer games rely heavily on feedback to make the game playing exerience enjoyable, and also, importantly, playable. Immediate feedback is given by audio sounds – gun shots, explosions, splats, screeches and so on. And of course, the visual control of the car, robot, or other avatar relies on the feedback from the screen motion in response to the players movements of keys, mouse, joystick or other controller.

Feedback can also be used, though, to affect the game play in other ways like keeping the difficulty level appropriate for the player. Sometimes this can be negative feedback, keeping the skill level of the computer controlled players similar to the live player. Other times, this can be positive feedback, giving the human player greater skills and resources as he achieves certain goals.

And in the all action world of computer games, these mechanisms are often combined together, so that rapid feedback is happening all the time in a cacophony of screen effects, sound effects, score indicators, colour changes and motion effects.

Of course, it isn’t always that rapid, in sport games like cricket or golf. Here feedback is sometimes given, as in real life, in the physcs of controlling the ball, or maybe by some tutorial from a computer training session.

There is a distinction to be made here between ‘obvious’ feedback, such as a score indicator, and ‘low-key feedback’, which is the kind of background which we hardly notice, such as the engine noise made by a car. Computer games have to make use of both to make them more life like and playable.

Virtual Reality

The idea of virtual reality has been changing a bit recently. The original thrust was to enclose the user in some kind of headgear, body suit, or a complete room. The user experience is then to see, hear, and maybe feel and touch a virtual world created by the computer game or simulator.

A new trend, largely driven by the Nintendo Wii, has been to all the user to move and see freely, but to use his body movements to control the virtual ‘person’ or avatar within the virtual environment. The Wii uses a hand held controller which senses position, orientation and acceleration, but recently Microsoft has demonstrated a concept system called Natal which uses video cameras to track the user’s position and movement. Somewhat alarmingly, it recognises people as they approach the camera, and greets them by name.

This isn’t true virtual reality, but is an interesting development in game technology.

In traditional VR, the user wears a head-mounted display (HMD) that presents a picture to each eye. It also measures the location of the user's head and the direction in which he is looking. This enables a computer to show the virtual world with a slightly different view for each eye.

Users can also hear sounds in a virtual world through earphones contained in the HMD. The position information is used to make the sounds appear to come from the right position.

And all this stuff relies on feedback just as we rely on feedback to use our muscles, joints and limbs. The VR kit provides feedback to the computer software, which in turn gives feedback to the user or game player via the VR kit.

So the Nintendo Wii not only senses where your hand is, and uses that to tell the computer where to position your virtual hand, it also can vibrate the hand uinit to give you sensory feedback. It does this, for example, when you hit the golf ball too hard, to simulate the shock you would feel through the club shaft if you did this in real life.

The term “haptics” refers to the sense of touch in a person's skin and muscles. Haptic feedback is tricky to implement, but some progress is being made using gloves and body suits to ‘touch’ virtual objects.

  

Music

Popular music changed in the 1960s. I know, I was there. When I was at school, my peer group all became keenly interested in jazz and blues in the light of the new music scene from the likes of Elvis and Buddy Holly. We listened to all the old names like John Lee Hooker, Lightning Hopkins, Muddy Waters, Bo Diddley, Jimmy Reed and many others. A local group started playing quite good blues, and I went to see them a few times at a pub called the Wooden Bridge near Guildford. They were called the Rolling Stones, and became quite popular after that. In fact, the pub rapidly became too small to hold the crowds, and I saw them later in some ramshackle buildings on Eel Pie Island, which, I seem to remember, burnt down not long afterwards.

Other rock guitarists were experimenting with using feedback to produce distorted ‘howl’ like sounds – notably of course, Hendrix, but also others like Eric Clapton, Jeff Beck and Pete Townshend of The Who. Even before that, guitarists like Guitar Slim had played around with feedback in the 1950s. And later on other groups like  Velvet Underground , Jefferson Airplane and The Grateful Dead experimented with  feedback effects.

The sound produced by this excessive feedback actually makes use of the limitations of the amplification system. As the feedback tries to make the sound ever louder, it is limited by the power of the amplifier, and can drive it into distortion, where the sound is no longer being amplified as it should be, but changed into a different, harsher sound. The extent of the feedback can be varied by moving the guitar closer or further from the loudspeaker, and so increasing or decreasing the amount of feedback. So Pete Townshend would wave his guitar around in front of the speaker, creating a kind of wobble effect.

Long before the swinging sixties, feedback had been utilized in two new musical instruments - the Theremin and Onde Martinot. These were invented in the 1920s, and used capacitance effects between the player and the instrument. They both involve the player moving his hand to change the pitch. The change in capacitance is used to control the frequency of an oscillator which mixes with another fixed frequency oscillator to produce a wide range of notes. Feedback is used by the player to control the movement of his hand and hence the music.

These instruments have been used in classical, film and pop music such as the Beachboys Good Vibrations.