Sound: Acoustics, Microphones, Sound design, and BGM

Published by Emil Abraham,

Topics covered in this article:
  • The nature of sound
  • Natural sound
  • Acoustics
    • Room acoustics
      • Live surroundings
      • Dead surroundings
  • Mono
  • Stereo
  • Surround
  • Microphones
    • Types by use: handheld, personal, shotgun, boundary, contact, studio
    • Directional features: omnidirectional, bidirectional, supercardioid
    • Types by electronic makeup: dynamic and condenser
  • Sound design
    • Basic role of sound in film:
    • Types of sound to accomplish the role: speech, music, sound effects
  • VO vs. Dubbing
  • Sync sound
  • Background music
    • Role of background music
The valuable contribution that sound makes to television cannot be underestimated. In a good production, sound is never a casual afterthought. It is an essential part of the production’s appeal.
People often think of television as pictures accompanied by sound. Yet when the best television productions are analyzed, people are usually surprised that most of the time it is the sound that conveys the information and stimulates the audience’s imagination, while the image itself can be a visual accompaniment. Audio has the power to help the audience conjure up mental images that enhance what is being seen.
Sounds are evocative. For example, consider an image of a couple of people leaning against a wall with the open sky as a background. If we hear noises of waves breaking and the shrill cry of birds, we quickly assume that the couple is near the seashore. Add the sound of children at play, and now we are sure that our subjects are near the beach. Replace all those sounds with the noise of a battle, explosions, and passing tanks, and they are immediately transported to a war zone. They might even appear particularly brave and unfazed, as they remain so calm in the middle of this tumult.
In fact, all we really have here is a shot of two people leaning on a wall. The wall itself might have been anywhere—up a mountain, in a desert, or near a replica in a studio. The location and the mood of the occasion have been con- jured up by the sound and our imagination.
Successful audio is a blend of two things:
■ Appropriate techniques. The way the equipment is used to capture the audio.
■ Appropriate artistic choices. How the sounds are selected and mixed.
The nature of sound
The world around us is filled with such an endless variety of sounds that it is difficult to believe each can be resolved into a single complex vibration pattern. When several sources sound together, their separate patterns combine into an even more complicated form. Yet our eardrums, the microphone diaphragm, and the loudspeaker all follow this combined vibration; and more miraculous still, our brain interprets the result.
The simplest possible sound vibrations make a regular sinusoidal movement, and we hear the pure tones from a tuning fork, a flute, or an audio oscillator. The faster this oscillation, the higher the pitch. Very slow vibrations (subsonic, below about 15 times a second) and extremely fast vibrations (ultrasonic, above about 20,000 times a second) fall outside our audible range. The fre- quency or rate of these vibrations is measured in hertz.
The stronger the sound’s vibrations (the greater their amplitude), the louder it seems. Slight vibrations are inaudible, whereas extremely loud sounds can become painful to listen to, as they exceed our threshold of feeling.
Few sources emit "pure" sounds. Most are a complex combination of the main note (the fundamental) and multiples of that note (harmonics or overtones)
The apparent quality of a sound will depend on the proportions or relative strengths of these harmonics.
Broadly speaking, a note played by a double bass, an oboe, or a bassoon can be judged by its overall quality. If the response of the audio system is not even over the whole audible range (because of filtering or limitations in the equip- ment), the proportions of the harmonics can change. Then the quality of the reproduced sound may no longer be recognizable as the original instrument.

Natural sound
Most video productions are made up of a series of shots, taken in whatever order is most convenient, and edited together later to form the final program. This approach has both advantages and drawbacks. As far as the program sound is concerned, there are several complications.
First of all, although the various shots in a sequence have been taken at different times, it is important that their quality and volume match when they are edited together. Otherwise there will be sudden jumps whenever the shot changes. If, for instance, a shot is taken of a person walking down a hallway, using a close mic, and then a side view is shot of the same action, using a more distant mic, the difference in the sound, when cutting from one shot to the other, could be quite noticeable. The overall effect would draw attention to the editing.
When editing together a sequence of images shot at different times, the back- ground sounds may not match. In the time between shooting one shot, repositioning the camera, adjusting the light, and then retaking the shot, the background noises often significantly change. Because the crew is busy, they may not notice that the background sounds are different. Sounds that we became accustomed to while shooting the scene—such as overhead aircraft, farm equipment, hammering, or typing—can have a nasty habit of instantly disappearing and reappearing when the shots are edited together.
When on location, it is a good habit to record a few minutes of ambient sound, background noise, on the recorder. It does not matter what the video is show- ing at this point, we are only really concerned with the audio. However, it is sometimes helpful to shoot the scene being recorded so that it gives the editor a visual reference as to where it was recorded. It is surprising how often this natural (NAT) sound or wild track comes in handy during audio editing for use as background sounds.
Even when shooting under what seems to be quiet conditions, there is a cer- tain amount of background noise from air conditioners, equipment hum, and so on. A wild track of this natural sound can be used later to cover any peri- ods where there is a break in the soundtrack during editing. Wild tracks also can help during those awkward moments when background sounds in succes- sive shots do not match. They can serve as a bridge to disguise when silent and sound shots are edited together.

Acoustics
You have only to compare sound in an empty room with the difference that occurs when that same room is furnished or filled with people to realize how acoustics alter sound quality. If we understand the basics of acoustics, we can avoid many of the audio problems that might arise during the production.
When a sound wave hits a hard surface (plastic, glass, tile, stone walls, metal), little is absorbed, so the reflected sound is almost as loud as the original. In fact, when its higher frequencies have actually been reinforced by this reflection, the sound bouncing off the surface can actually sound brighter and sharper.
When a sound wave hits a soft surface (curtains, couches, rugs), some of its energy is absorbed within the material. Higher notes are the most absorbed, so the sound reflected from this sort of surface is not only quieter than the original sound wave, but it lacks the higher frequencies. Its quality is more mellow, less resonant, even dull and muted. Certain soft materials absorb the sound so well that virtually none is reflected.
Where there are a lot of hard surfaces around (as in a bathroom, a large hall, or a church), a place can become extremely reverberant or live. Sound waves rebound from one surface to another so easily that the original and the reflected versions, completely intermixed, are heard. This can cause consider- able changes in the overall sound quality and significantly degrade its clarity.
When surroundings are reverberant, reflections are often heard seconds after the sound itself has stopped; in extreme cases, these sounds reflect as a repeated echo. Whether reverberations add richness to the original sound or simply con- fuse it will vary with the design of the space, the position of the sound source, the pitch and quality of the sound, and the position of the microphone (or mic).
If, on the other hand, the sound is made in a place with many absorbent sur- faces, both the original sound and any reflections can be significantly muffled. Under these dead conditions, the direct sound can be heard with few reflections from the surroundings. Even a loud noise such as a handclap or a gunshot will not carry far and dies away quickly. When outside, in an open area, sound can be very dead. This is due to the air quickly absorbing the sound because there are few reflecting surfaces.
We all know how dead sound seems to be when we are outside in the open. Open-air sound is weak and does not travel far because the air quickly absorbs it and there are few reflecting surfaces. Microphones often have to get closer to a subject than normal to pick up sufficient sound, especially if a person is speaking quietly.
Open-air sound has a characteristic quality that we immediately recognize; it has an absence of reflected sounds, combined with a lack of top and bass. This effect can be difficult to imitate convincingly in the studio, even when the subject is completely surrounded with highly absorbent acoustic panels.
Acoustics often influence where the microphone is positioned. To avoid unwanted reflections in live surroundings, the mic needs to be placed relatively close to the subject. If working in dead surroundings, a close mic is necessary, because the sound does not carry well. When the surroundings are noisy, a close mic helps the voice (or other sound) to be heard clearly above the unwanted sounds.
However, there can be problems if a mic is placed too close to the source. Sound quality is generally coarsened, and the bass can be over- emphasized. The audience can become very aware of the noise of breathing, sibilants (s), blasting from explosive p’s, b’s, t’s, and even clicks from the subject’s teeth striking together. Placed close to an instrument, a mic can reveal various mechanical noises such as key clicks, bow scrapes, and so on.
Room Acoustics
Live surroundings: When a room contains predominantly hard surfaces, the sound is strongly reflected. The microphone picks up many of these reflections, reinforcing and coloring the direct sound pickup.
Dead surroundings: When surfaces in a room are very sound absorbent, the direct sound waves strike walls, floor, ceiling, furnishings, and are largely lost. The microphone may pick up only a few weak reflections.
Mono sound
In everyday life, each member of the audience is used to listening with the aid of two ears. As listeners compare these two separate sound images of the external world, they build up a three-dimensional impression from which the direction and distance of sound is estimated.
Non-stereo television sound is not as sophisticated as this. It presents a "single eared" monaural ("mono") representation of sound in space. The only clue to distance is loudness, and direction cannot be conveyed at all. When listening to mono reproduction, we are not able to distinguish between direct and reflected sounds, as we can when listening in stereo. Instead, these sounds become inter- mixed, so that the combined sound is often muddy and less distinct. In mono sound, we become much more aware of the effects of reverberation.
Because the audience cannot easily distinguish direction and distance, the mono microphone needs to be carefully positioned.
Audio personnel need to be careful to consider the following:
■ Too many sound reflections are not picked up.

■ Louder sounds do not mask a quieter sound (particularly in an
orchestra).

■ Extraneous sounds do not interfere with the ones we want to hear.
Stereo sound
Stereo sound creates an illusion of space and dimension. It enhances clarity. Stereo gives the viewer the ability to localize the direction of the sound. This localization gives the audience a sense of depth, a spatial awareness of the visual image and the sound. However, because the speakers in television receivers are close together, the effect can be somewhat limited. Sound quality and realism are enhanced, but our impressions of direction and depth are less obvious.
To simplify sound pickup, many practitioners mix central mono speech with stereo effects and music. When using a stereo microphone, take care to maintain direction (such as mic left to camera left) and to hold the mic still; otherwise the stereo image will move around. In a stereo system, reverberation even appears more pronounced, and extraneous noises such as wind, ventilation, and footsteps are more prominent because they have direction, rather than merging with the overall background.
Disney introduced surround sound to the cinemas with the movie Fantasia, released in 1940. Three channels were used behind the theater screen with three additional speakers used on either side and at the rear. However, implementing this system was extremely expensive, and the system was used in only two theaters.
Surround sound
Surround sound can provide a sense of envelopment when mixed correctly. Instead of the one channel for mono or the two channels for stereo, 5.1 surround has six discrete (distinct, individual) channels: left front, right front (sometimes called stereo left and right), center, a subwoofer for low-frequency effects (LFE), left rear, and right rear speakers (sometimes called surround left and right). To present the feeling of depth, direction, and realism, audio personnel pan between the five main channels and route effects to the LFE channel.

Microphones
A microphone is a device that converts acoustical pressure waves (sound) into electrical signals. All microphones have a diaphragm, membrane, or other element in that vibrates sympathetically to the arriving acoustic wave fronts. A sensor in the microphone measures the movement of the vibrating element, and converts the mechanical vibrations into electrical signals. These electrical signals can then be amplified (as in at a concert), transmitted (as in a radio station or telephone), stored (as in a compact disk or MP3), or processed (as in a speech recognition system).
All microphones convert sound energy into electrical energy, but there are many different ways of doing the job, using electrostatics, electromagnetism, piezo-electric effects or even the change in resistance of carbon granules. The vast majority of mics used in these applications are either capacitor (electrostatic) or dynamic (electromagnetic) models. Both types employ a moving diaphragm to capture the sound, but make use of a different electrical principle for converting the mechanical energy into an electrical signal. The efficiency of this conversion is very important, because the amounts of acoustic energy produced by voices and musical instruments are so small.
There are six common microphone designs:
  • Hand held—the type held by on-camera talent or used for on-location interviews
  • Personal mic (lavaliere/clip-on mic)— Whether hung from a cord around the neck (lavaliere) or clipped to clothing, these are all referred to as personal mics.
  • Shotgun—used for on-location production to pick up sounds a moderate distance from the camera
  • Boundary effect microphone—also called PZ or PZM mics. These rely primarily on reflected sounds from a hard surface such as a tabletop.
  • Contact mics—which pick up sound by being in direct physical contact with the sound source. These mics are generally mounted on musical instruments.
  • Studio microphones—the largest category of microphone. These include a number of application designs that we’ll discuss. These six categories include different transducer types, or approaches to converting sound waves into electrical energy.

Directional features
Microphones do not all behave in the same way. Some are designed to be non- directional (omnidirectional), meaning they can pick up equally well sounds coming from all directions. Others are directional, meaning they can pick up sounds directly in front of them clearly but are comparatively deaf to sounds in all other directions. A further design has a bidirectional or "figure-of-eight" pat- tern, meaning it can pick up equally well both forward and backward, but it is deaf on either side.
The advantage of an omnidirectional mic is that it can pick up sound equally well over a wide area. It is great for covering a group of people or someone who is moving around. The disadvantage is that it cannot discriminate between the sound you want to hear and unwanted sounds such as reflections from walls, noises from nearby people or equipment, ventilation noise, footsteps, and so on. The more reverberant the surroundings, the worse the problem. The mic must be positioned so that it is closer to the wanted sounds than to the extraneous noises. This mic is great for picking up ambient or natural (NAT) sounds.
When a directional mic is pointed at the desired sound, it will tend to ignore sounds from other directions, providing a much cleaner result.
  • The omnidirectional pickup pattern is equally sensitive in all directions, generally rugged, and not too susceptible to impact shock. This mic cannot distinguish between direct and reflected sounds, so it must be placed close to the sound source.
  • The directional (or cardioid) mic pickup pattern. This broad, heart-shaped pickup pattern (roughly 160o) is insensitive on its rear side.
  • Use a supercardioid (or highly directional) pickup pattern wherever you want extremely selective pickup, to avoid environmental noises, or for distance sources.
  • On the other hand, the directional mic needs to be aimed very carefully. It is also important to make sure that the audio source does not move out of the main pickup zone; if it does, the source will be "off mic." The off-mic sound becomes weaker, there will probably be high- note losses, and the audience may hear what the mic is pointed at instead of the desired source.
  • There are several forms of unidirectional pickup patterns. The cardioid or heart- shaped pattern is broad enough for general use but not over-selective, whereas the super- or hyper- cardioid response has also a limited pickup area at its rear, to receive reflected sounds.
Popular types of microphone
There are two predominant methods for converting sound energy to an electrical equivalent signal: electrodynamic and electrostatic, better known as dynamic and condenser.
  • Dynamic microphones are the most rugged, provide good quality sound, and are not easily distorted by loud sounds such as nearby drums. These mics need little or no regular maintenance. They can be handheld without causing unwanted "handling noise" and used in all types of microphone mountings. However, they are just as high quality as the condenser microphone.
  • The condenser microphone produces very high audio quality and is ideal for picking up music. A significant advantage to the condenser is that it can be very small, making it the logical choice for a shotgun, lavalier mic, and other miniature microphones. The condenser mic is generally powered by an inboard battery, phantom powered audio board, or a special power supply. The electret condenser microphone has a permanent charge applied when it is manufactured, which remains for the life of the microphone and does not need to be externally powered.

Sound Design
It is impossible to overstate how important a role audio plays in the film viewing experience. While it’s perfectly natural to be drawn to the visual side of filmmaking, those striking visuals don’t hold the same weight without strong cinematic sound design to back them up. Sound design is how filmmakers flesh out the aural world of a film to enhance the mood, atmosphere, and/or tone. Sound design components include sound effects or SFX sound design, mixing, Foley sound design, dialogue, and music. Sound design is the final and most important element needed to create an immersive experience for the audience.
Sound design for film is just as important in creating the illusion as imagery. With today's technology and ubiquitous CGI, what you see on screen is almost never "real." The same can be said for sound — what you hear in a movie is always manipulated in some way.
When done thoughtfully, sound design for film is a way to enhance the visual storytelling. It can give life, authenticity, and dimension to an otherwise flat, moving picture.
There are two basic roles of sound in film. These are: storytelling and story supporting.
  • Storytelling is the most important characteristic of the films in the "sound era", and is possible in film using dialogues, monologues or off-narration.
  • Story supporting relates on the sound effects that enhance the tension in film and suggest the audience how to feel. Special sound effects and music are the basic tools which enable it. The sources for the sound used in film could be: recordings made during principal photography on sets, sound effects libraries and customized recordings, and music, both that composed from the film and from pre-existing sources.
The basic roles of sound in film are accomplished utilizing different types of sound in film, such as:
  • speech (dialogue, monologue, over voice)
  • music (recorded music, rerecorded music, live music, background music, etc.)
  • sound effects
    • Hard or "cut" effects
    • Foley sound effects (mixed with music)
    • Ambience (backgrounds)
    • Design sound effects
Speech
Speech is the most revolutionary thing which appeared in film history. It changed totally the visualisation of movies, which now differate very much from the films in the silent era. Today the speech is one of the most important tools for understandig the story of the film, so it is very important to be understandable and as more realistic, as it could be.
Music
At the beginning, music in film was used for two very different purposes at once: to drown the noise of the projectors and to give emotional atmosphere. As cinema developed commercially, the music became more elaborate and played a larger and larger part in the show as a whole. There are quite a range of different appliance of music in the film according to its role in the movie. Music could be specially composed for the film, or could be used already made commercial music. The first step in the process of composing the music is that the composer, the director and the spervising sound editor or sound designer spot the picture. Spotting refers to going through the picture and noting where music should be present and what kind it should be. The particular problem is music editing, because it should be cut of to make the musical sence within the scene, and it is not always easy to achieve. One trick to accomplish music editing is to make cuts that will be masked by other soundon the sound track, in a case that inaudible cut is not possible to obtain.
Sound effects
    • The hard or cut effect. Almost every sound we hear at the movies that isn't dialogue or music is a sound effect. It is the expectation of the audience that everything we see on the screen, that in a real life makes noise, should be heard, and thus covere by a hard sound effect. Hard in this context means that the sound was obtained from a source other than a production sound, Foley, or ambience, and the sound was cut in by a sound-effects editor to match the picture. The hard effects are never recorded on the set, thus the basic sources of these effects are sound-effects libraries. It is common that sound designer doesn’t record the library by himself, but uses all made commercial or private sound-effects libraries.
    • Foley effects. Foley sound effects are those made in a recording studio called a Foley stage, while watching the picture a Foley artist performs the acting more or less synchroniously with the picture (the perfect example of Foley effects are footsteps, who are always made with this sound effect). The Foley sound effects are the most responsable for realistic impression of the movies. However, they often exaggerate the real-life sounds to make them audible. Foley recording was invented early in the history of film sound by a man named Jacke Foley, working at the time at Universal Studious. Many early sound pictures had dialogue and music but no feeling of the noise of movement. Soon editors started cutting together footstep sounds for actors, but would use the same tracks over and over. Foley got the idea of projecting the moving image in a sound stage and recording sounds in sync with the actors' movements, using different surfaces and an array of props. The idea was that many sounds could be recorded to fit to the time they appear on the screen by simply performing the action in sync with the picture, and recording it. Today, Foley recording is likely to involve a multitrack recorder or workstation so that different record passes can be used to add layers or different effects, building up to a complete whole.
    • Ambience is the recording of background sounds present on the location or set. It gives artificial "presence" of the space. Ambience most typically consists of more or less continuous sound, often with a low-frequency emphasis associated with background noise of spaces. It plays a significant role in scene continuity. If ambience stays constant across the picture cut, the audience becomes the impression that the action stays in the same space. Conversely, if there is an ambience change at a picture change, the audience get the impression of the completely new scene. Ambience may even be overlapped across certain scene transitions, either to create an effect of the former scene lingering into a new one or to anticipate a cut to a new scene.
    • Design sound effects are sounds that do not normally occur in nature, or are impossible to record in nature. These sounds are used to suggest futuristic technology, or are used in a musical fashion to create an emotional mood. These kind of sound effects were first inaugurated with the film King Kong (1933), and later developed in the field of SF film genre.

To summarise, sound effects are added after filming during the editing process to give the film an authentic sense of location or period, or to give it a particular mood. They may be employed by audio post production houses, or work on a freelance basis and provide their own digital audio workstations. They are also likely to own their own recording equipment.
Sound designers are responsible for providing any required sounds to accompany screen action. They work closely with the production mixer, sound supervisor, the editor, and the director to create original sound elements. They may work with the director to create the entire soundtrack, or be hired just to create one kind of effect. To be a good sound designer, good communication skills are needed, along with imagination and creative flair to produce original sound elements and effects. The ability to accept direction and work well with others is also important. Sound designers must have a good understanding of acoustics, and an expert knowledge of sound recording and analog and digital editing techniques

Voice-over vs. Dubbing
Voice-over, is mostly narrative in nature, does not lip-synch and does not transmit the tonality and overall richness of what is being said in the original footage.
Dubbing, also referred to as Language Replacement, is recorded by professional voice actors and the audio track of the original video footage is mixed with the alternate language recordings of the dialogue. Word choice is extremely important as the translated video must be synchronized with the lip movement of the actors on-screen. The result, as compared with voice-over, is much more precise, both from translation (and ADAPTATION) of the original spoken content, as well as a technical delivery point of view. A well- crafted dub is unnoticeable to the viewer, as it is truly an "acted" voice recording that uses sound engineering and editing to ensure true lip synching - making the original actor seemingly mouth his/her dialogue in the target language.
When to use both?
Voice-over is frequently utilized in news-related segments, digital learning or documentary clips that are short and where translation is the primary objective. Why?
  • V/O has more of a "translation" only aspect to it, with less emphasis on nuance of tone and emotive content.
  • V/O tends to work best for shorter segments of content, such as footage from in-the-field reporting, or conference proceedings where the voice-over is really the recording of a live interpreter (hence the term "UN Style").
  • V/O, by its very nature, constitutes an additional soundtrack to the original. While this conveys "authenticity" in a reporting environment, it also risks becoming distracting for longer form content.

Dubbing should be used when information retention is paramount:
  • Well beyond spoken words, tonality, nuance, dialect, accents etc. combine to convey a richer message. For entertainment products, such as films and performance driven videos, dubbing is in fact the only true way to capture the totality of the original content’s intent.
  • When the video content is conveying a large amount of high-impact information, such as in high impact training environments or sophisticated lectures with information intensive presentation slides, the retention of the information presented to a foreign language audience is significantly enhanced when the audience is not distracted by competing audio feeds (such as V/O) or graphic localization (subtitles). Dubbing makes the content look like it is native to the audience’s ear.

Sync Sound
There are two large categories of sound: synchronous and nonsynchronous. These two categories define all possible film sounds.
Synchronous sound includes all noises whose origins can be seen on-screen: in a "two-shot" conversation between two lovers you simultaneously see their lips flapping and hear the words they speak. In a barroom brawl you see and hear the chair crash over the cowboy's head. Synchronous sound can be either ambient (sound recorded during the filming of a sequence and retained in the final cut) or a sound effect, the product of a Foley or ADR (Automated Dialog Replacement) technicians. In other words, that dialogue you hear could have been live, or it could have been dubbed if the filmmakers were not satisfied with the sound on-screen.
Non-synchronous sound is any noise whose origin you can't see: that gunshot in the dark that almost hits the hero; the train whistle offscreen signifying that the two lovers must break their embrace as one leaves. Non-synchronous sound can also be ambient: While we watch children at play, a mother calls them home just offscreen. More frequently, however, nonsynchronous sound is the product of postproduction technicians determining the emotional and intellectual impact of a certain scene through sound. At the simplest level, music is used to determine how the audience's response to a particular moment.

Background Music
The function of music in the movies is a very wide field. Music can serve several purposes that are either important on the emotional side of the movie or help/enhance the storytelling. It is not only helpful but essential for any director/producer to keep the music in mind when planning/shooting the movie. For example collages that practically don’t work at all without film music can have a fantastic effect later with the appropriate music.
Role of Background Music in films
Setting the tone: Music sets the tone for a movie. It gives the audience an idea about the genre, level of intensity and the kind of movie it is. Even though it’s a subconscious effect this happens quite fast. Dialogue and video create two inputs; music creates a third input in the mind of the audience which helps them to think and interpret the scenes in a certain way. Sometimes this is made obvious and other times it is subtle.
Contrary thoughts: It is possible to create music contrary to the scene, which gives the audience a different perspective. This is often used in plots which have a twist. For example, imagine that a villain character is actually a hero and the film maker wants to convey that towards the end of the story. Music can help by creating a perspective from the audience’s point of view rather than revealing the character’s actual personality in the beginning.
Another example could be to use music for creating a false sense of anticipation and then backing off. This tricks the audience into thinking that something is going to happen, but it actually doesn’t.
Thematic Development: There is also scope for thematic development, as in it is possible to use a couple of musical themes and then develop them as the story progresses. Composers may use a variety of techniques to develop a musical theme, like increasing the size of the orchestration, developing the melody of the theme as the story progresses, etc.
Character themes: Character themes help the audience to understand and connect the dots as far as the plot is concerned. For example, if there’s a bad guy in the story and we have his character theme, every time he is about to come if that music is played, the audience gets a hint that something bad is going to happen.
Custom Sound Pallet: Analogues to musical thematic development, is the development of the soundscape for the movie. The pallet of sound used in a movie can be the collective decision of the director, producer and music director. Creating a unique blend of instruments and sounds give the film an aural personality. Its not always necessary to use new sounds/instruments for every project, but just by using the same sounds/instruments in a different way each time gives depth in the soundscape and makes it unique to that particular project. This has a subconscious effect on the audience and helps them to relate to the story better.
Perception of time: Pacing of the story and screenplay may be slow or fast depending on the director’s vision and film making technique used. The role of music here is to create movement and alter the apparent pacing of the video cuts. The perception of time can be manipulated by varying the tempo of the music according to the intensity of the scene. If this is not done effectively the story may appear to be draggy/sped up without it being able to retain the attention of the audience.
Dynamics: Every good film has dynamics. There are scenes which are lighter and scenes which are more intense. Music can emphasize on the gravity of the situations to the right extent. Sometimes even silence acts a powerful tool to help create dynamics. When there is no music, attention shifts to the Foley. Interplay between sound and music helps in creating an immersive experience where the audience is pulled into the story.
Expressing emotions: Music can do a lot more than just make you feel happy or sad. It can make you think and feel in a certain way about the characters, their dialogues and the storyline. This helps the audience relate to the characters better and it also subconsciously creates a perspective about the movie. The right music can help to accentuate emotions or create contrast. For example, if you have a more or less neutral scene with an expressionless guy looking out of his apartment’s window, the music can provide a hint about what the man is feeling or thinking.
Gluing scenes together: Films often have montages that help to tell parts of the story. These can be interpreted in various ways, so music gives the audience a better idea of how these scenes connect with each other and with the story.
Music helps to smoothen the video edit and blend scenes together to make the story flow better. However, its easy to lose the connectivity between scenes if the music is more contrasting than it should be.
Time period, Culture and Location: Music can also be used to enhance the characteristics of a location or time period. For example, if the movie is set in the 15th century and based in India, the music can help create the vibe of that era and location by clever use of traditional Indian folk instruments and musical styles influenced by the culture of that time period.
Mickey-mousing: This is an old school idea that dates back to the time when music was first introduced in film scoring. In this technique, anything happening on screen is coupled with a similar impact in the music. This is largely used in Charlie Chaplin’s movies, Tom and Jerry and Disney movies for kids. It makes the actions on screen appear more obvious so it is widely used in the comedy genre. You could think of this being more like musical sound effects.