3 Recording Sounds

In chapter 2 we discussed how library sounds can be under copyright, and can also become overused and recognized by audiences. When we can, it is always best to use our own recorded sounds rather than those of a sound library. Of course, sometimes sound libraries are necessary, because we don’t often have the access, time, or budget to go record the cockpit of a B52 bomber, a Japanese Shinkansen bullet train, or a lion’s roar, and so on. But if we are serious about sound design, we should start recording and collecting our own sounds into our own sound library. Part of that comes down to not wanting to duplicate what’s already out there, and part of it is about having an original sound that is ours, so that we own the copyright and have control over how it gets used. In this chapter, we’ll begin exploring recorded sound, looking at some basic aspects of microphones, the associated tools, and recording techniques. Like listening, the more we practice, the better we will get at recording sound, and the more comfortable we will get with the equipment involved.

3.1 Audio Slating

When we record sound, it’s important to slate our audio. An audio slate is equivalent to the slate used in film production, which you’ve probably seen: someone scribbles some notes on a clapperboard and yells, “Take one!” and snaps the clapper, also known as a slate. The audio slate isn’t on a clapperboard but is just us speaking some notes into the microphone at the start of a recording, and is designed to give us some basic information: time of day, and date; temperature and wind conditions (if outside); location; subject being recorded; recording gear used. In other words, any information we may need later to identify or share the file. Without slating, we might forget which of the sounds was which bird or which car engine we recorded, or what the sound itself was. Going back to files months or years later, having the information about the sound file can be really helpful.

Be sure to also leave two seconds at the start and end of the recording; you can cut this down later if needed, but it gives you some room for fade-ins and outs. If we’re recording with a video camera or multiple microphones, it helps to slate the multiple recording devices with a hand clap if we’re not using a clapperboard, to help with synchronization across devices later, although auto-sync is getting much better. If we can’t slate the sound at the beginning because we whipped out the recorder at the last second to catch a fleeting moment, then slate at the end of the file before hitting “stop”—this is called tail slating. At the tail end, we might also want to note things that happened during the recording (for instance, “airplane flew overhead half way into that, rendering it useless. Delete this file”). These notes help us quickly navigate useful or useless files when we come to organize our files later.

For example, we might slate a field recording like this:

February 14, 2019, 9:45 a.m. Clear, sunny day, with snow and ice on the ground. Backyard of my house recording the cheerful male cardinal that comes to sing in my blue spruce tree, approximately 10 m from my house where I’m standing inside the doorway out of the wind. Using a Sennheiser MKH-416 shotgun mic on the H4N recorder.

Imagine if we didn’t know what a cardinal sounded like, but knew what one looked like, and we were collecting a lot of bird sounds that day. Going back six months later and trying to figure out which one of thirty files recorded that day was the cardinal sound might be useless. Likewise, what if we’re recording a bunch of sounds with several different microphones, and we really loved one, but couldn’t remember which mic we used to go record similar sounds with? We’d have to repeat the whole recording again. Slating also helps with naming the files later, with cataloging the files in our own library, and with sharing them with others. It may seem like a fiddle at first, but your future self will thank you.

3.2 Stereo or Mono Recording?

You’ve probably come across the terms mono and stereo on music recordings (or “monaural”/“monophonic” and “stereophonic”). Back in the early twentieth century, mono files were the norm, because the earlier record players had a single speaker. Mono sound was originally designed to play the sound through that one speaker, and records until the 1950s were recorded in mono. By the late 1950s and early 1960s, recording technology and home consumer audio products had advanced, and people started using two channels, mapped to two speakers to play sound—stereo. Each speaker would have a different channel—a different track played to that one speaker. Bands started to play with stereo techniques, which enabled them to create a sense of space in the recording by panning a sound to one side (adjusting the recording so that, for instance, the lead guitar would be heard in the left speaker, while the bass guitar might be in the right). Stereo came to be associated with “quality,” and mono was phased out by the late 1960s.

Many people believe “more is better” in most aspects of their lives, and while stereo enhances the playback of many types of sounds, when it comes to recording sound, stereo is not always better than mono. Unless we are recording a wide space, recording with stereo microphones, or the sound is moving, stereo is often unnecessary, since we will likely have the same sound in both the left and right channels. In that case, we are just doubling the file size by duplicating the same signal, taking up more room on our recorder’s flash card than necessary. We are effectively creating not stereo, but dual-mono. Most one-shot effects in sound libraries, and most vocals for dialogue are recorded in mono because there is no need for stereo. For many purposes, if we need a stereo file, we can resample our file later to split the mono signal into two and digitally alter the stereo position (we’ll come back to this later). On the other hand, recording ambience—where we need a sense of space—or recording something that is moving is often done in stereo. For this reason, a recording device will give us the choice to switch between mono and stereo. Stereo recording requires two microphones, or a specially designed stereo mic, since we need to capture two separate channels; most of the recording we’ll focus on will be mono.

3.3 Microphones and Microphone Selection

There are many different types of microphones, and they range in cost from a couple of dollars to many thousands of dollars. What difference does the microphone make? Quite a lot! Each type of mic has a different purpose, so we can’t really say which type of mic is “better” than another, only which is better for a specific purpose. There is so much to microphone selection and use that many books have been written about it. We will just cover the basics.

The first thing to understand is that microphones amplify sound in different ways in terms of the technology they use. A microphone is a transducer—it converts energy from one form to another, and the technology used to do that conversion determines the type of microphone it is. The most common microphones we encounter are probably dynamic or condenser microphones.

3.3.1 Dynamic Microphones

Dynamic microphones have a diaphragm with a long coil of wire wrapped around a magnet. Sound pressure moves the diaphragm, which moves the coil, causing an electrical current to flow. Dynamic microphones are quite rugged (they can take a bit of beating and be dropped on stage, for instance), usually comparatively affordable, and don’t require batteries or external power. They also tend to have a great signal-to-noise ratio. We can usually tell if a microphone needs external power by the presence of an on/off switch on the mic: if it has a switch, it usually doesn’t need external power. Dynamic mics can also be fairly resistant to environmental changes like temperature or humidity.

If we take a look at the frequency response charts of dynamic mics, though, we notice that they often have a boost in one specific range, and therefore are usually selected for a specific purpose based on this response. Dynamic mics are best for low- to mid-frequency sounds like drums, electric guitar, or vocals. We can also buy specialized kick drum mics, or bass mics, designed for low-frequency sounds. A popular example of a dynamic mic is the Shure SM57, which has a great response for vocals, and is very rugged (you may have seen artists throw them on stage, pick them up again and keep singing). They’re much better for recording very loud sounds (like gunshots and drums), as well as recording outdoors, because they’re pretty solid.

3.3.2 Condenser Microphones

The second most common microphone type used in professional recording is the condenser mic. These use a lightweight membrane with a capacitor on either side of it. Sound pressure on the membrane fluctuates the capacitor, creating an electrical signal. Condenser mics have a more uniform frequency response than dynamic mics, particularly in the high and low frequencies. They are great for getting detail in a sound, but are more delicate—a loud sound too close to the mic can blow the membrane and destroy the microphone. They are also prone to problems in high temperatures or high humidity, and they are generally more expensive. They may require external power sources, known as phantom power, which amplifies the weak voltage they output (more and more modern condensers have built-in power now, so you’ll have to figure out what you need by listening or looking at the manual). Condenser mics, because they can capture high-frequency sounds, work better on instruments that have high frequencies or lots of harmonics in higher frequencies, such as cymbals or acoustic guitar. The size of the diaphragm influences the frequency response. A large diaphragm is used for voice, for instance, while smaller diaphragms get a better response on the higher frequencies. A condenser microphone that is popular with professionals is the Neumann U87. It costs several thousand dollars, but you get what you pay for: the frequency response is nearly flat across the entire spectrum, making for a highly accurate recording.

Condenser and dynamic mics have different transient responses. Transient response refers to how quickly the mic responds to changes in the sound. Dynamic mics don’t respond as quickly, so their transient response isn’t as accurate as a condenser mic. Most people who work in sound gather a collection of microphones for recordings, because they each have their own unique characteristics. Small-diaphragm condenser microphones are an easy default while you get used to microphones, and are probably the most versatile mics. The mics on most handheld recorders are small-diaphragm condensers, because they are the most useful for a variety of types of recording.

3.3.3 Other Types of Microphones

The vast majority of microphones you will encounter in professional recording environments will be dynamic or condenser mics. We’ll be building and exploring other types of microphones below, but some other types of mics include:

Ribbon microphones: A thin strip or ribbon of aluminum or film is moved between two magnets by the vibration of sound. These are very delicate and very expensive, but modern technology is improving their durability and lowering their cost.

USB microphones: USB is becoming a more commonplace way to use microphones for podcasts or if you’re on a budget. Most USB microphones are small-diaphragm condenser microphones, like the Blue Yeti. They are designed to plug into a computer and record digitally, rather than for use with professional recorders.

Stereo microphones: Stereo microphones are dual microphones, designed to pick up two signals from the same sound at once from different directions—usually in what is known as an X/Y position. The angle between the microphones typically varies between about 90 to 135 degrees, with a wider angle corresponding to a wider stereo image.

Binaural microphones: These are dual mics designed to be worn on or in the ears. We’ll get into binaural sound in chapter 7, but for now, you’re unlikely to encounter them except in specialist circumstances. They are usually condenser mics.

Surround microphones: With new technologies, surround sound microphones have become available, such as Holophones, or the DPA d:mension 5100, a 5.1 surround mic (shaped like and called by some “the bicycle seat”). These are large capsules with an array of microphones inside the capsule that capture each direction. In this way, they’re designed to capture five separate sounds into five different microphones on location. Other approaches include double-mic approaches that use processors to segregate the signal. They are usually condenser mics.

Lavalier microphones: Lavalier (“lav”) and lapel mics are designed to be clipped onto the clothing—you will often see these on people being interviewed on television. While they are fine for voice on sets, they’re not usually used for other sounds, although they’re handy for some tasks where you need a small microphone.

Contact microphones: Contact mics consist of a piezoelectric disc that must be placed directly onto a vibrating surface (i.e. in contact with it). These can record some really interesting sounds. Hydrophones, underwater microphones, are usually built with piezo discs as well, with the addition of a transducer and some form of a container to protect the wiring from the water.

3.3.4 Polar Patterns

In addition to responding to frequencies differently, microphones also have directional properties. We’ll be dealing in more depth with directionality and spatial audio later, but for now, a basic understanding of how mics pick up sound is useful. The directionality of a microphone is described using what are known as polar patterns, or sometimes pick-up patterns, because they illustrate where the mic picks up sound. Polar patterns describe the directionality of a microphone on a sphere, but they’re often visualized in a two-dimensional circle.

Omnidirectional (or just omni, as in “all”) microphones pick up sound in all directions evenly. Assuming the microphone is at 0 degrees, an omni microphone’s polar pattern shows similar sensitivity in the 360° range. This means an omni mic isn’t aimed at a particular sound source—it will pick up sound all around it regardless. At higher frequencies omni mics can become directional, meaning that the sound will need to be in front and on axis (see below) to be picked up, so high-frequency sound arriving from behind the mic can sound a bit muddied or dull.

Unidirectional microphones will pick up most sound in one direction—for this reason, they’re usually just called directional mics. They may pick up some sound from other directions, but they are more sensitive to one particular direction. Cardioid (heart-shaped) patterns are the most common—with most sensitivity on axis (0°) and least to the sides, at 180°, but with a spread of about 130°. Unidirectional mics will pick up less of the ambient sound than omni mics. Shotgun microphones are commonly used in film and field recording to pick up a specific sound, as they are very unidirectional microphones. Even microphones that are called unidirectional are not completely unidirectional, though, and they will pick up some sound behind and/or to the sides. Shotgun mics are useful when we need to focus on one sound and filter out a lot of ambience—while an omni or cardioid mic might be useful, for instance, in picking up the ambience of a forest, a shotgun is useful for picking out a specific bird in that one tree, and focusing on that.

Bidirectional mics usually pick up in front and back, with less coverage at the sides. Supercardioid and hypercardioid patterns for instance will pick up sound in front about 115° for supercardioid and about 105° for hypercardioid, with varying degrees in the rear.

It’s important to remember that the polar patterns are described as they record in optimal conditions, and are determined in anechoic chambers (special rooms that have no reflections). Putting a microphone near a wall or floor will change the sound that gets picked up (we’ll talk about the environment and reflections in chapter 4). Some mics allow you to change the polar pattern at recording time. Others even allow you to change it afterward using software such as Sennheiser’s Ambeo Pattern for the MKH 800 Twin mic.

Exercise 3.1 Microphone Selection

If you have access to multiple microphones, try recording the same sound with different microphones to hear how they pick the sound up differently. What differences can you hear? Look up the microphone’s frequency response. Did the differences in what you hear align with the frequency response charts? Don’t forget to slate your audio!

Exercise 3.2 Build a Contact Mic

A contact microphone picks up vibrations through contact with objects—sounds transferred through solids, rather than air. A piezo is a metal disk with ceramic piezoelectric crystals in the middle. The vibration produces a buzzer sound, so you’ll find piezo speakers in all kinds of toys that make sound that you can hack.

Equipment
a piezo disc, sometimes called a “buzzer,” of about 27 to 30 mm
about 30cm of balanced microphone cable, e.g., Mogami W2582, or ¼″ guitar cable
a ¼″ in-line female mono jack (TS)
wire strippers/cutters, solder, and soldering iron

The piezo has two terminals: the inner terminal (the signal) and the outer metal disk (the ground), so we need to use a cable that has two conductors (e.g,. a microphone cable). Strip about 5cm off the end of the cable, which should reveal the two conductor wires inside. Separate the copper shield wires and the conductor wires (blue or red and clear). Twist the two separate groups of wires into separate bundles.

The sound signal will be weak, and so you’ll get a lot more high-frequency sound. Although you can record louder sounds with a contact mic, to get more delicate sounds and a balance of lower frequencies, you will need to purchase an amplifier/preamp.

Exercise 3.3 Use an Inductor Coil to Record Hidden Sound

Inductor coils convert electromagnetic radio waves into sound. We can quickly and easily build an inductor coil, or quite cheaply purchase them online as telephone pickets or “circuit sniffers.” These electromagnetic waves can be found in any electronic devices, from lights to remote controls. Inductor coils can even pick up electromagnetic radio waves from far away in space, such as meteors or the aurora borealis. The more powerful the inductor, the more they pick up waves.

3.4 Recording Accessories

Many microphone accessories are available for purchase to improve our recording quality. These include:

Boom pole: A boom pole is a pole designed to be held by the hands with a microphone at one end. Some boom poles are designed with the cable inside the pole to reduce the sound of the cable rubbing on the pole, but we can also strap the cable to the pole with tape, clips or elastic bands. The important thing to look for is one that is lightweight but sturdy, and you feel comfortable holding for some time. Some people prefer to wear gloves while holding the boom pole to reduce hand noise, so you may want to try out some gloves and see if you can still keep your grip.

Microphone stand: Mic stands are really useful when you are recording solo, since we need our hands free, so holding a boom often isn’t practical. Mic stands are usually some variety of tripod with a longer pole that can be positioned on top. The weight of the mic will alter the balance of the tripod, so be sure to check that it’s got a stable base, and is not going to drop the mic onto the ground once the mic is attached.

Shock mounts (figure 3.4): Shock mounts are designed to reduce handling noise and mechanical noise of microphone stands, and they usually suspend the microphone using elastic cords, and attach to the end of a boom pole or mic stand. Shock mounts come in a lot of shapes and varieties, for indoor or outdoor use. Most mics will come with their own fitted holder to attach to a microphone stand (and some will come with their own shock mount built into the holders). There are differences between American and European threading sizes, so you will need an adaptor to attach some of these to different-sized stands.

Windscreens: These come in many different types, from basic pop filters designed for indoor use to reduce popping on the plosives in speech, to windjammers, “dead cats”/wombats, “blimpies,” “zeppelins,” and “furries” put over the microphone unit for use in outdoor windy environments. Most microphones will come with a foam windscreen for very basic reduction of environmental noise. It’s good to have a collection as they have advantages and disadvantages in different environments.

Pads: You can purchase pads that will reduce the decibels picked up by a microphone in order to record in very loud spaces, or with very loud sounds. They fit on the end of the mic before the cable, to reduce the signal going into the cable.

Phantom power: As described above, some microphones require a phantom power setup. Some of these are battery operated, and some are built into professional recorders. It’s important to know if your mic needs power. Phantom power units can be attached to mics before they hit your recorder, but most recorders now have a built-in phantom power.

Preamps: Sometimes just called a “pre,” the preamp converts the weak output of some microphones into louder signals for recording. As with phantom power, you can buy external units, but many professional recording devices have built-in preamps that can be switched on or off.

Pop filter (figure 3.5): These are used for vocals. The screen is a simple barrier that scatters the puff of air caused by the plosives in our speech (“P” and “B” in particular). The pop screen should be about 10 cm from the mic.

Plugs and cables: Most professional mics have XLR plugs. We may need adaptors if our input takes ¼″ TS (tip sleeve) or TRS (tip ring sleeve), balanced or unbalanced phone cables, like headphone jacks. Others have USB adaptors. Knowing what our microphone cables are and what adaptors we need to connect to our recording device is important. The more adaptors we have to add, the more chance of there being interference or problems with the recording. Different types of line inputs have different requirements in terms of sensitivity. An external sound card, for inst ance, might have TS line inputs, which are usually for stereo recording and tend to require a signal boost of a preamp unless they have a built in preamp. Balanced cables have signals run along three wires: positive, negative, and ground. Balanced cables eliminate noise with noise cancellation. XLR and TRS cables are balanced. Unbalanced cables can add noise to a signal, so should be avoided for recording unless you are recording in very short distances (5 or 6 meters).

Recorder: Portable recorders are commonly used inside and outside the studio. Zoom and Tascam make some very popular, affordable recorders. Many will have built-in phantom power and preamps, can input XLR or ¼″ balanced or unbalanced cables, 1/8″ (3.5 mm) mic/line mini phone jack, mic and line-level signals (no external preamp required). Look for one that also has built-in mics you can use in a pinch. It’s also possible to purchase XLR adaptors for a smartphone and record onto the phone from a standard mic, and there are some mics designed with smartphone adaptors that can now fit onto the phone.

It’s best to purchase a dedicated recorder if you can afford one, because it will have all of the additional settings you may need, like phantom power and preamps, but a phone adaptor is handy for everyday travel purposes. Some expensive recorders also exist—like the Sound Devices 702. The Sound Devices is usually up and running within just a couple of seconds of it being turned on, whereas (in my experience) other pocket recorders the Zoom can sometimes take over two minutes to boot up and be ready. In addition, there are settings like time codes for film that can be used on the more expensive equipment, but for basic sound design purposes a portable recorder like the Zoom H4N is a perfect balance of affordability and capability. Be sure to check if you also need to purchase a memory card with your device.

3.5 Microphone Position

Where we place the microphone can significantly alter the sound that gets recorded. Of course, paying attention to the polar pattern is going to be relevant when we use a directional microphone—in that case, the axis or angle of the microphone is going to determine how much of the direct sound we pick up. How we hold the microphone is also going to influence the sound. As described above, most professional microphones are designed to be used with shock absorbers, which suspend the microphone with elastic cables to reduce the sound of handling. Where we put the microphone stand or boom pole is also going to influence the sound that gets picked up (e.g., the height of the microphone is going to pick up more footstep sounds if it’s close to the ground, and more breathing if it’s close to head height).

Side-address versus top-address: The position of the capsule inside the microphone will determine whether the mic should be pointed at the sound from the top or from the side. Hand-held mics (like those used on stage for voice) are top-address, meaning the capsule is at the top of the microphone, so the mic should be pointed at the sound with the top. Side-address mics have the capsules pointed at the side, so the side should be pointed at the sound source. Usually condensers are side-address, and dynamic mics are top-address, but not always. Consult the manual for the microphone to discover more about the mic.

Axis: Microphones are generally designed to record on-axis (that is, with the end pointed directly at a 0° angle toward the source), with the most accurate recording having the correct address pointing at the sound source. As the angle of the microphone toward or away from a sound changes, the frequency response of the sound that the mic picks up will change. The amplitude will drop, and high frequencies and harmonics will tend to get lost as you move off-axis, leading to a slightly “muddier” sound. On the other hand, if we’re recording certain sounds, like voice, being off-axis can reduce the pops, pick up more “room tone,” and lead to a warmer sound (figure 3.7).

Exercise 3.4 Off-Axis Recording

Try recording the same sound with the microphone positioned at different axes. What changes do you hear in the frequencies that get picked up and the amount of environmental sound?

Distance: The distance from the microphone to the sound source also influences the sound. The invention of the electric microphone led to a new style of singing in the 1940s, called crooning, exemplified by Billie Holiday, Bing Crosby, and others. The fact that the microphone could pick up more delicate sounds meant that singers could be much softer than previous recordings, and the mic picked up nonvocal emotional effects like breath, the tongue clicking on the teeth, and other sounds that previously couldn’t be heard in music recordings. These delicate sounds place us in a very intimate position relative to the singer, since to hear those types of sounds in “real life,” we’d have to be standing very close to the vocalist. Physical distance, then, can create a perceptual distance (we’ll come back to this below).

Ambient sound will be picked up by any microphone. How much ambience we want should be a factor in our selection of microphone, in addition to how close we place the microphone to the sound source. Directional microphones can be placed farther away from sound sources because they won’t pick up as much ambience as omni or bidirectional mics. An omni mic will need to be about twice as near to a sound source to reduce ambience. As a microphone is moved closer to the source, more of the direct source and less of the environmental sounds get picked up.

Proximity effect: As a microphone is moved closer to a source, the bass response will increase. If we place a directional microphone close to a source (i.e., about 30 cm), we will get a proximity effect of having emphasized low frequency (< 200 Hz) content. This can make a man’s voice sound rich and deep, but can impact speech intelligibility and can make low frequency content in nonvocal sounds sound a bit muddy, and can make some instruments (e.g., acoustic guitar) sound too “boomy.” The proximity effect is most apparent on a bidirectional microphone, and least (or not at all) on omni microphones.

Exercise 3.5 Proximity Effect

Record sounds at close proximity and then back off to a distance of more than 30 cm without adjusting the input gain. Can you hear a difference? What changes as the sound gets closer to the mic?

Feedback: Feedback loops are created when the microphone is too close to an amplifier/speaker monitor, or turned up too loudly, resulting in an increasing loop of loudness that gets amplified, creating a high-frequency ringing sound. Move away from the amplifier (and point the microphone away from the amp/monitor), move closer to the sound source, or turn down the microphone’s volume (or input gain—see below) to reduce feedback. Flatter response mics are less likely to cause feedback, and non-omni mics will reduce feedback noise. Feedback can be a wanted effect (the Beatles, for instance, probably used it first on “I Feel Fine” in 1964, and other bands have used it since), but usually it’s not wanted at recording time.

Phasing: When we are using two or more microphones, we can run into phasing problems. When the same sound arrives at two more mics at different times, because of the difference in arrival time, a destructive interference pattern can occur, causing a “whooshing” sound. You may have noticed this in a classroom if the instructor was wearing a lapel microphone and had the lectern microphone also turned on. As they move around the room, phasing effects may be picked up, as the time it takes for their voice to reach the amplifier varies between the two microphones, shifting one signal out of phase with the other. The destructive interference we discovered in chapter 2 can happen between just a few frequencies, and we may not notice at recording, but we may notice later that we’re missing out some frequencies because they’ve been canceled out by phasing issues (figure 3.9).

Phasing can also occur if we have a single microphone close to a reflective surface. The reflection and the direct sound occur at slightly different times, resulting in a phasing effect. If we need to put a microphone close to a surface, putting something soft on the surface will cut the reflections. We’ll take a look at intentional phasing in chapter 4, but usually it’s best not to introduce phasing at recording even if it is a desired effect.

Input gain: The gain is the volume of the input of the microphone. If we plug in headphones, gain is not the same as the volume we hear in our headphones: The volume knob adjusts the amplitude of what we hear, and the gain knob adjusts the amplitude of what is being recorded. We need to look at the meters on our recording device to determine the input volume. We typically want to record where the meters are all green just touching to the edge of the (usually yellow) warning (this may also be red). If it goes into the red it’s peaking, and the sound will clip. When we record at too high or “hot” an amplitude, the sound will distort and become “crunchy” sounding. This is known as clipping, as we learned in the previous chapter, and is very difficult to recover from. It’s important when we record not to clip the audio. Even if we want a distorted sound, it’s better not to record it clipped but instead to add distortion effects later onto a clean sound, so we can determine exactly how much distortion we want.

Volume meters are handy to track how hot the gain is. In Audacity, we can monitor before we start recording by right-clicking on the record level meter and then selecting “start monitoring” (figure 3.10). You’ll see a red-yellow-green bar appear. The right side of the bar is the current peak of the amplitude. You’ll also see a line that appears (which can be red, yellow, or green depending on the gain), which is the recent peak. Beyond that is the maximum peak, a blue bar that sets the maximum peak in that channel during the session—how high you’ve gone since starting. There is also a clipping indicator, a red bar to the right of the maximum peak that is highlighted if we have clipped part of our sample.

What is the best volume to record a sound? It can depend on what we’re recording, but generally, stay in the green: many people believe that a peak at –20 dB is the optimum recording level. As long as we know we’re not risking clipping, we can increase that. If we want an intimate sound but getting too close will cause the signal to clip even at a low gain, we can put a pad on the microphone to reduce the input gain into the recorder.

Exercise 3.6 Input Gain

Make some different sounds with a variety of objects at different distances, and see if you can guess what the best input gain is before you monitor the sound to check.

3.5.1 Stereo Recording

As described earlier, we tend to record spot sounds in mono, and ambience or sounds with some width or movement in stereo. Stereo recording involves two microphones: each mono signal from each mic is assigned to a channel (left or right) in the stereo file. We want to use stereo if we want a difference between the channels: a difference in timing or a difference in frequency. We want a time difference, for instance, if we want to record a helicopter flying from our right to the left. We may also want a difference in frequency: as we saw, changing the axis will change the frequencies that get picked up, so recording a sound with two different axes means we can bring out different aspects of that sound.

How we position the mics depends not only on what we want to pick up, but also on the polar pattern of the mic. I mentioned the X/Y position in discussing stereo mics above, but if we are using omni mics, we might want to position them in A/B position: side by side, at a width we decide to be as wide as we want (figure 3.12). The trouble with A/B positioning is that we can run into phase cancelation problems from the difference in timing between the two mics. The X/Y position uses directional microphones, and reduces phase cancelation, since the mics are positioned at the same point so that the sound arrives at the same time on both mics. Sometimes, if the sounds are mixed down to mono, we can run into phase cancelation, but it’s rare that we’d want to record in stereo and mix to mono.

Mid/side (or M/S) uses (usually) one cardioid or omni mic, and one bidirectional (figure 3.13) mic. The bidirectional mic is placed at a 90° angle from the source to record the “side,” and the other mic points at the source, and functions as the “mid” (figure 3.13). The stereo width can be adjusted to increase or decrease the spread between the two channels, allowing us more freedom than X/Y. The difficulty with mid/side stereo recording is how to mix the signals together—they need to be matrixed and decoded (the side signal is split into two separate channels and then merged again). Because of this difficulty, some recorders, like the Zoom H4N, have a built-in M/S decoder to make the process much easier.

3.5.2 Proxemics

As we saw above, recording distance is picked up by our brains and affects our perceptual distance to the sound. It’s possible to think of the distancing effect of microphones in terms of proxemics. Proxemics is the social construction of distance between people: we all have a distance that feels intimate, personal, social, or public depending on how well we know people. The more comfortable we are someone, the closer they can physically be to us without us feeling uncomfortable. Most of us have heard someone complain about someone invading their “personal space”: we can also invade their personal space perceptually with sound!

The intimate zone is, as the name suggests, for intimate contact or whispering: it’s from 0 to 46 cm (18 inches) from us. The personal zone is for people we’re comfortable around, but not intimate with (friends and family), and ranges from the intimate zone (46 cm) out to about 120 cm (4 feet): but this distance also depends on context. We may be fine with someone being a meter away from us in the queue at the grocery store, but when more room is available, as when we’re standing around outside, if someone enters that zone it may feel uncomfortable. We fully expect people to be in our personal or even intimate zone on a packed subway train, although most of us feel uncomfortable with strangers that close to us. The social zone is for people we know socially, but more on an acquaintance level, and ranges from the personal zone up to 3.7 meters (12 feet). Finally, there is the public zone, which is farther than about 3.7 meters from us (figure 3.14). These proxemic zones are not hard-and-fast rules, and vary by culture.

In film and television, camera angles are sometimes spoken of and used in terms of these proxemic zones (e.g., Ferguson and Ferguson 1978). For example, close-ups and extreme close-ups may draw our attention and place particular significance on an object or person by bringing us intimately close. Medium close-ups are in the personal zone, social distances are characterized by medium and full shots, and so on. The distance from the camera to the object creates a subjective perspective that mimics social and emotional distances. Similar effects can be created with sound recording. A microphone in the same apparent distances, or proxemic zones, as those described above can create a similar effect: closely miked sounds feel very intimate, and as the sense of space in the file (more environmental sound) increases, the perceptual distance to the sound changes, and with it our sense of where the sound is physically located. The microphone is only one aspect of this perception, though, and it can be altered with effects: for instance, adding reverberation (see chapter 4) to a closely miked subject can reduce the sense of intimacy.

Exercise 3.7 Proxemics in Music

Find some examples of music you listen with closely miked vocals or guitar. What impact does that have on you as a listener? How does it compare with other songs where the distance from the sound is farther?

Exercise 3.8 Recording Distance

Record a sound at several distances, adjusting the gain but increasing the distance from the microphone to sound source, starting in the intimate zone and then moving farther out. What are the changes you notice in the sound acoustically and perceptually?

Exercise 3.9 ASMR

You’re probably familiar with the ASMR YouTube trend, and if you’re not familiar, these are videos where recordings of quiet sound and whispered voice are very closely miked so as to induce an autonomous sensory meridian response, commonly known as tingles or chills. Intimate miking is just that—very intimate—and so it invokes a very intimate response from our bodies. Record your own ASMR session with closely miked sound effects. What type of mic did you choose, and why?

3.6 Creative Recording

The best way to get comfortable with new equipment is just to try it out in as many different situations as you can think of.

Exercise 3.10 Recording Your Daily Sound Listening Practice

Write your daily sound log. Record the sound at the same time. Then, turn up your recording and play it back: what sounds did you miss?

Exercise 3.11 Found Sound

Go to the hardware store. Find three things that make an interesting sound and buy them and record them. How many sounds can you get out of each object? Upload the sounds to freesound.org and get some feedback from users on your recording. Then repeat the exercise with garage sales (yard sales/car boot sales), a secondhand store, and a grocery store.

Exercise 3.12 Same Sound, Different Place

Record the same sound in different locations around your house and outside. What do you notice about how the sound changes?

Exercise 3.13 Moving Sound

Find a sound that is moving, such as a small creek or stream. Stand as close to the running water as possible and record the sound. Move four steps back and repeat. Kneel down and repeat again. Lie prone and repeat again, with the mic as close as possible to the sound. Play back and note your observations (adapted from Dorritie 2003).

Exercise 3.14 Repeat, Repeat, Repeat

Choose a common sound (e.g., a door closing). Record as many examples of that sound as you can in a one-hour timeframe. How many did you find? What is the greatest variation between two of those sounds?

Exercise 3.15 Creatively Making Sound (Partner Exercise)

We often use a variety of really creative approaches to making sounds. While the added visuals of movies and games helps the interpretation (which we’ll look at later), the sound itself can often evoke interesting results. Try to create a sound you can’t record outright (e.g., a leg breaking, a bullet flying past, a spaceship, etc.) by recording another sound in its place, and then have a partner guess what you are intending to use the sound for.

3.7 Prototyping Sounds

We often don’t have the materials at hand to describe a sound we want to use, so we might use our voice to mimic the sound we’re going for to share with someone or use as a temporary placeholder. This is sometimes called vocal sketching (see, e.g., Ekman and Rinott 2010). Learning how to prototype sounds verbally is a useful skill. Michael Winslow, sometimes called the “man of 10,000 sound effects,” is a human beatboxer who can make all kinds of sounds with his mouth—he is best known for his roles in some 1980s movies like Police Academy and Spaceballs. Sometimes, mouth sounds are used in the prototyping phase of design. Some games have even been made with all of their sound effects created by mouth, like Hidden Folks.

Exercise 3.16 Making a Sound with the Mouth

Imagine someone is shoveling different materials: snow, sand, gravel, coal. How does the sound change? Make the sounds with your mouth (adapted from Schafer 1992).

Exercise 3.17 Vocal Sketching

Try making a short composition using only mouth sounds.

Exercise 3.18 Vocal Sketching Part II (Partner Exercise)

Once you’ve recorded a sound composition, give it to a partner and have them find recorded sound effects not made with the mouth that match what you prototyped. Alternatively, find that sound yourself and see how close you came to it, then try to get closer.

Exercise 3.19 Record a Sound Poem

Sound poems poems that are meant to be read aloud, often containing nonsense words. Some examples are “Karawane” by the Dada artist Hugo Ball, or “Zang Tumb Tuuum” by the Italian futurist F. T. Marinetti. Find a sound poem and record it with your own vocalizations.

Reading and Listening Guide

Cathy Van Eck, Between Air and Electricity: Microphones and Loudspeakers as Musical Instruments (2017)

Van Eck takes us on a history of the use of microphones and speakers in music and as music, including some early experiments with surround sound, feedback, and other techniques that are commonplace today. A must-read for anyone interested in sound art, as well as sound in performance art and experimental music.

Steve McCaffery and bpNichol, eds., Sound Poetry: A Catalogue (1978)

You can find this book floating around on the internet. It’s a catalog from the Eleventh International Sound Poetry Festival held in Toronto in 1978. The introduction provides a useful overview of sound poetry in Dada and Futurist works and describes different genres of sound poetry, before the book presents some sound poems and writing about sound poetry.

There is a playlist of sound poems at studyingsound.org. You might also check YouTube for recordings: try Kurt Schwitters, Raoul Hausmann, and Jaap Blonk.

Karen Collins and Ruth Dockwray, “Sonic Proxemics and the Art of Persuasion: An Analytical Framework” (2015)

In this essay, Ruth Dockwray and I explore the role of sonic proxemics in public service announcements, and present a framework for the analysis of understanding the proxemics of sound as a rhetorical device in audiovisual media.

Gino Sigismondi, Tim Vear, and Rick Waller, Shure Microphone Techniques for Recording (2014)

This is an overview of different microphone types and techniques by manufacturer Shure. They’re obviously inclined to speak mostly about their own microphones, but there is a lot of useful information about the types of microphones and techniques for recording.