Identifying the characteristics of the recording environment

Establishing the physical space in which your recording activities will occur is a critical first step in building your voiceover recording capabilities.

The physical environment in which the actual recording process takes place can range from a simple office or home environment to a soundproof studio environment with a voice isolation booth. For most applications of digital voiceover narration, it is usually not necessary to record in a completely soundproof environment, however, the quality of the final product will be adversely impacted by the presence of excessive ambient sound within the recording environment.

Identifying this element of your recording setup will help you determine the level of audio quality that you can expect to achieve (when recording within that space), identify any limitations within the space, select the appropriate audio equipment, and identify other issues that can impact the recording space and equipment setup.

For example, if you are planning to record at your cubicle desk in a busy office, spending large sums of money on highly-sensitive professional microphones and processing is likely a waste of money, unless you want to clearly hear the sounds of computer fans and telephone conversations taking place within the adjoining office on your recordings.

In this section, we will take a brief look at some of the factors to consider when evaluating the environment in which you will be capturing your audio recordings, identifying any limitations, and suggesting enhancements to the recording environment to help you to optimize the quality of your recordings.

Portable recording systems vs. a static recording location

Sony_PCMD50_Portable_Recorder

Example of a professional field recorder with integrated microphones

One initial determination regarding your recording environment is whether you will be using a dedicated recording environment vs. moving your recording activities to one or more locations.

If your recording location will move, or is located within a multi-use space where you will need to bring in your recording equipment for each session, you should plan on a recording setup that is relatively portable.

Compact digital audio “field recorder” style recording devices come in various configurations. These devices typically come with attached high quality microphones, and the ability to plug in standard professional microphones. One equipment option for maximum location flexibility is to use a self-contained portable recording system. Portable systems designed for music recording often have capabilities to simultaneously record multiple tracks and include an integrated mixer.  This type of audio recording equipment can be moved between various locations within your office or home, or to remote locations, and used to capture interviews or voice performances via an attached microphone.

Other types of portable digital audio recorders are designed for recording multitrack music performances, and include multiple microphone inputs, mixers and on-board editing capabilities.

The use of a portable audio recording method gives you maximum flexibility in selecting your recording location. You can move to quiet areas of your office or home to record your segments. Or you can set up an area to have the right conditions for when you record, and move your equipment to and from this location for your recording sessions.

These types of portable systems can capture high quality audio, but usually have limited or no editing capabilities, and usually require use of a separate computer to edit and finalize the audio files. You will learn more above these devices in a later section that focuses on equipment.

A variation on this approach is to use a notebook computer with headphones and a USB microphone (or portable external USB/Firewire audio interface and external microphones), and move the notebook-based setup to the room in which you plan to capture the audio. Or you could set up a desktop PC on a wheeled cart that you can move to the recording location within a specific building on an as-needed basis. 

Compare the portable approach with a static setup, in which you have a desk, a computer and monitor, and any outboard processing equipment, set up in a manner that will allow you to record your audio segments in that specific location. This type of setup can allow you to optimize your space and equipment setup in a manner that will produce the highest quality recordings.

Selecting an appropriate location for recording

Any location that you will consistently use for your recording activities should have appropriate conditions for recording high quality sound.

A location with minimal ambient sounds is most desirable. It is best to select a location that has minimal sounds or noises from conversations, phones ringing, loudspeaker announcements, background music, doors opening and closing, elevators, computer fans, and other people-related activities.  Other sources of noise can include:

  • If you are recording at your home in a home office or spare room, pay attention to sounds from appliances such as refrigerators and washers/dryers, children playing, televisions, etc.
  • Sounds from heating/cooling (HVAC) systems may sound quiet under normal circumstances, but these sounds will typically be very noticeable in voice recordings captured using a sensitive microphone.
  • Sounds from persons walking or working on floors above or below your recording space may be noticeable on your recordings, especially audio recordings captured in home studios with wooden floors.
  • Outside noises can often be picked up by microphones when recording voiceover, such as street noise, aircraft flying overhead at lower altitudes, persons talking loudly as they walk past on an adjacent sidewalk, music from car stereos, and lawnmowers.

Keep in mind that noise levels can vary throughout the day, and by the days of the week. For example, deliveries for the retailer next door may result in loud backup beeps from a delivery truck in the mornings, or your children running around in the upper floors of your house can make the afternoons, evenings or weekends unsuitable as times to record. So try to become aware of how the noise situation changes based on the time of day and day of the week, and whether this is compatible with your planned times for recording.

The amount of ambient noise from heating and cooling systems may also vary throughout year. When evaluating a space, think about the impacts of cold winters and hot summers, and how these will impact the amount of ambient noise from your HVAC system within the space.

Noises from the street and aircraft passing overhead may vary throughout the day, getting more prominent during rush hour, and dropping off at night. So your home office that is too noisy during the day may be fine for making recording in the evenings

The easiest way to evaluate the level of ambient sounds within a room is to sit and listen during the time periods when you would be using the room for recording. If you have access to audio recording equipment, try recording someone doing a test voiceover segment, then continue recording at the same level for another minute or two without anyone speaking, and then with and carefully review the recording to see how prominent these noises appear. Listen to the segments of room-only sound to get a clear idea of what noises are being picked up, and then listen to the voiceover test to see if you can hear the background noises under your recorded voiceover.

The result of your review of potential recording spaces may cause you to exclude some locations or specific rooms from consideration as a recording environment. These will be the rooms with major noise issues that you cannot minimize or overcome.

Some noises may be under your control, such as being able to shut off the HVAC system or dishwasher while you are recording, or having the family stay out of the living room while you are recording in the basement office below. Since you will generally have control over when you record and how long each session will take, being able to “turn off” offending noises for a 30 minute recording session can be a reasonable solution to a specific noise issue.

Other less prominent noise issues can often be addressed via some simple methods of acoustic sound deadening or isolation treatment, such as installing sound absorbing foams, heavy curtains over windows, or other approaches.

For example, the noise from the computer fan can be reduced by moving the computer to another area and using extended length cables for the keyboard, mouse and monitor. Or you can cover your computer CPU case with a heavy rug or foam isolation, making sure to leave an opening for the cooling fan air. You may also be able to install a low noise fan as well to reduce these noises.

How does the room itself “sound”?

Once you have identified potential spaces that have noise characteristics that are suitable for you to record sound, you should get an idea of how your voice performance will sound within the space. This means how the surfaces within the room, such as ceilings, floors and furniture, reflect sounds within the room and the length of time it takes for those reflections to diminish to silence (called “reverberation” and “decay”).

The most familiar example of reverberation is the sound enhancement we perceive when talking or singing inside of a tiled shower stall or bathroom. Reverberation is different from an echo, in that you hear an echo as a distinct reflection of the original sound, while reverberation sounds more like a continued sustain of the original sound during which the sound waves reflect and combine to create a slower decay of the sound energy.

This type of reverberation is often considered desirable when used to enhance the sound of a vocal performance. However, for a voiceover performance, it is not usually a desirable enhancement. In most cases for both vocals and voiceover, it is preferable to record a performance without any noticeable “colorization” by reverberation, and then later add synthetic reverberation effects during editing and mixing in a manner that allows the editor the maximum amount of control over the specific characteristics of the effects.

Why is this important for a voiceover performance?  When you set up a microphone within a room space, it picks up the direct sound from the performer, but also picks up reflections of this sound, depending on the levels of reflection and reverberation within the room. If the room surfaces create a high amount of reflections, the reverberations can continue for a noticeable period (i.e., have a long “decay” time).

Reverberation and refection are not necessarily an entirely negative colorization of the sound. Performance spaces are specifically designed to control these reflections to create a pleasing sound decay within the room. The key issue to consider within your voiceover recording space is whether these reflections are excessive and noticeable, creating undesirable sound colorization that will reduce the quality of your voice recordings.

Room

Reflection and reverberation are frequency dependent – that is, different types of surfaces in various rooms will reflect and reverberate sounds at higher or lower frequencies at different levels (or amplitudes). This is due to the size and shape of reflective surfaces in the room, and the reflective qualities of the materials of which of these services are composed. This means that areas of a rooms may have increased reverberation of some frequencies while allowing others to diminish. For example, wall placement may cause low frequencies to sound “boomy” in some locations, while other rooms may only reflect high frequency sounds.

Each type of room will have its own acoustic characteristics. For example, a standard office with drywall walls and suspended ceilings will be less reflective than a hard masonry wall. Small rooms typically produce more prominent reverberation of voices than large rooms because the level of energy in a voice sound is usually not strong enough to reach the far wall at a level that will create a noticeable reflection, or the larger rooms will have furnishings that absorb excessive sound energy.

Rooms with parallel reflective walls will create more reverberation than rooms with walls placed at angles, because the parallel walls will allow the sound to bounce multiple times between each wall, and these reflections will combine to build at some frequencies and cancel out other frequencies. Sometimes this effect creates a standing wave, in which reflections combine at specific resonant frequency. You can identify a standing wave in a reflective room by clapping once loudly, and listening for a ringing sound.

The furniture in the room will also impact the amount of reverberation. Padded fabrics, such as sofas or thick curtains, will not reflect sound, and usually absorb sound waves in a desirable manner. Many manufacturers produce foam soundproofing panels that are placed on the walls to absorb sound and reduce reflections in the same manner.

Reverberation and reflections also become an issue when selecting the proper placement of loudspeakers that you will use when editing your audio files. You need to strive to achieve a sound from your loudspeakers that you use to edit and process your recordings that is as accurate as possible, uncolored by the room space, so that your recordings will sound the way you want when played back through other audio systems. For example, placing loudspeakers in the corner of a room in a manner that results in an increase in the perceived volume of the lower frequencies elements of your recording can prompt the sound editor to reduce the volume of these frequencies by using equalization during editing. This can make the resulting edited recordings sound too “thin” on other systems, because the playback system used during editing providing an inaccurate, “colorized” playback of the sound.

Listening to the room

A number of professional tools are available to analyze the reverberation and other acoustic characteristics within a room. These typically consist of a very sensitive microphone, connected to a software-based instrument that includes a loudspeaker that generates sound at various frequencies and amplitudes.  The device then analyzes the reflections of these generated sounds and identifies the resulting level of reverberation and decay at various frequencies within the room. These tools provide an objective sand accurate profile of a room’s acoustic characteristics, and are used by professionals when designing recording or performance spaces.

However, for a basic voiceover recording space, the easiest method to evaluate reflectivity and reverberation within a room is to move about the room while speaking and making other sounds, and listening to any reverberation that is present within the space, or using a recording device to capture the room sounds for later examination. Try clapping your hands to make a loud sharp sound, and listen for how the reverberation decays over time. Then speak loudly in a low and then higher pitch voice, and see if you can hear a sustained reverberation. If you happen to have audio recording capabilities, record these sounds within the room to evaluate later. This simple approach will likely give you a sufficient understanding of how the characteristics of the room space will colorize voice recordings.

Controlling problem sounds within a room

If your assessment of the acoustics within a room suggests that you will experience undesirable levels of reflection and reverberation while recording or editing your performances, you can take steps to reduce these undesirable effects to an acceptable level.

Acoustic treatments used to address these types of issues can range from low-cost home-grown solutions to expensive commercial professional acoustic controls. For example, professional dedicated production facilities often spend substantial funds to design an optimal acoustic space for performance and recording. This includes specifying wall angles, using a mix of specific materials for walls and other surfaces, and including installing sophisticated sound absorption design elements within the space. Persons recording in smaller home studios with smaller budgets can hang thick blankets on the walls to minimize reverberations and reflections, or place sound absorbing foam panels on portions of the walls.

The approach that you finally select will be based on your budget, the effectiveness of the treatments, and the need for a professional appearance to reassure clients.  But keep in mind that smaller scale recording efforts can often adequately control unruly sounding rooms by using a mix of lower cost and/or home-grown acoustic treatment solutions.
Many professional recording facilities use full or partial audio isolation booths designed to block infiltration of external sounds, while deadening reflections within the booth. Both permanent and portable versions of these types of sound isolation booths are available, with varying levels of sound isolation, and offer a quick solution for problem spaces. Booths can be placed within a building to provide a self-contained space that isolates the performer from outside noises, with non-reflective interior surfaces specifically intended for recording voiceover or vocal performances.

Absorb 2

absorb_1

Examples of desktop partial isolation enclosure (left) and standing isolation panels (right). Images courtesy of ClearSonic Manufacturing.

Prices for sound isolation enclosures can range from $1000 to $5000 or more, depending on the level of isolation they provide. Booths typically require a dedicated location within your facility where the booth will be placed or installed. Booths are the best solution when faced with a noisy recording environment, and/or a room with other undesirable acoustic issues. However, in many cases, an acceptable level of quality can often be achieved without spending thousands of dollars on a professional level sound isolation booth.

Controlling reflections and reverberation within the room can often be accomplished via proper placement of sound reflecting and absorbing materials within the room. Professional commercial studios use a mixture of surfaces, some reflective, and some absorbing, throughout a room.  Surfaces can consist of smooth wood and rough stone, specially constructed sound absorbing panels and “traps” that are designed to absorb sounds within specific frequency ranges, and other soft materials that absorb or disperse sound. Surfaces are often oriented at specific angles in an effort to disperse sound reflections in a more random manner to produces less prominent room ambiance, and reduce problems associated with resonant reflections with an excessively long decay.

 

foam.jpg

Sound absorbing foam on walls within the recording area

studio 1.jpg

 

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Examples of professional recording spaces
utilizing a range of surfaces for acoustic control

Examples of acoustic treatments that can be appropriate for voiceover studios include:

  • foam 2Commercial sound absorbing foam panels are available from a number of manufacturers in a wide range of configurations to match the room sizes and layouts to solve the particular acoustic problem you need to address. These panels can be placed at strategic locations throughout the room to deaden or reduce the reflections from that position or capture specific problem frequencies. Perform an Internet search for “Auralex,” “Sonex,” or “sound absorbing panels” for examples of products and prices.
  • Room furnishings, such as sofas, curtains, cloth wall hangings and other elements, can be specifically selected and positioned to help reduce problem reflectivity within a space.
  • Blankets or other fabric wall decorations can be hung on the walls for a low budget acoustic treatment solution. Wall hangings can also be used to cover unsightly foams or other absorbing materials to improve the overall appearance of the acoustic treatments.

For home and office recording setups with budget constraints, or rooms that serve multiple purposes that prevent the configuration and installation of permanent acoustic treatments, an acoustic approach using this type of “soft” interior decorating of this type can often provide acceptable results at a low cost that are also visually attractive.

Prior to committing funds to deaden the ambiance in a room, perform some test recordings at various locations around the room to see if some areas that are usable as recording locations have more suitable ambiance characteristics than other areas. The geometry of the room (angles of the surfaces and distances from surfaces) will make a difference in the amount and characteristics of the ambiance that will appear on your recordings. For example, recording in a corner with hard walls can increase the level of reflections, and areas with hard flooring instead of carpet will usually sound livelier. So if you have flexibility in your recording location within a space, first examine the various areas of the room to see if it makes a difference on your test recordings.

Ambiance control enclosures

Smaller recording setups often use smaller sound absorbing panels placed behind or around the microphone, or place the microphone inside of a box-style sound absorbing device. These box-style devices will isolate some of the room ambience, but will not be completely effective due to the directionality of the microphone.  A cardioid microphone is most sensitive in the direction it is pointed, which in this case is outside of the isolated area in order to capture the speaker’s voice, resulting in the microphone still picking up ambience and other sounds coming from that direction.

Mic and absorbtion

Noise absorbing enclosure used to
reduce sound reflections

 

It is also important to keep in mind that the prominence of some undesirable noises or room sounds can be reduced via audio processing that occurs later in the production process.

For example, equalization can reduce the prominence of the specific frequencies where reverberation occurs within your room to a limited degree.

Noise gates are hardware or software processing functions that reduce the perceived noise levels by rapidly shutting off the microphone sound during the pauses between your statements, which has the effect of making the room appear to sound silent. The room noises and ambience are still recorded along with your voice, but the higher volume level of your voice usually covers up much of the room ambience and noise in a manner that can often conceal minor to moderate ambience and noise issues (you will learn about equalization and noise gates in a later chapter of this book).

Automated noise control software functions (either as part of the recording software, or as plug-in added features) are specifically designed to analyze the ambience and noise characteristics present within the recording and reduce the prominence of these aspects of the recorded sound while retaining the voice recording. However, it is always best practice to configure your room in a manner that produces the best environment for recording, and not depend on “fixing it in the mix” during later stages of production.

Another option if your room is too “lively” is to select a less sensitive microphone for voiceover recording. Sensitive condenser microphones will pick up more room ambience than a dynamic microphone, so selecting a dynamic microphone that is placed close to the performer may be another potential workaround when you cannot adequately control ambience and noise within the recording space. You will learn about microphone selection is a later chapter of this book.

Room ambience can impact the accuracy of your loudspeakers when monitoring playback of recordings

As noted earlier, excessive room ambience can also impact the quality of your audio system playback through your loudspeakers, usually referred to as “monitors” within an audio studio. The playback of your recordings through the monitors will usually be at a higher volume than your spoken voice, and the character of this sound will be affected by the reflective characteristics of your room, often by emphasizing some frequencies over others. The impact of these acoustic issues will change your perception of the sound from the monitors, and can cause you to make adjustments to the sound to compensate (usually changing equalization), which will cause your final edited recordings to sound different on other systems or through headphones. While this is generally more of an issue when recording and mixing (editing) musical recordings, it can impact the process for editing a voiceover recording to a limited degree. So it is usually important to be aware of these issues and take a few steps to minimize colorization of your sound during playback and editing.

Some examples of acoustic problem areas when dealing with monitors include:

  • “Boominess,” or reflectionsthat serve to enhance the lower frequency bass response of your loudspeakers. This can typically occur when your speakers are located too close to a wall or corner of the room.
  • Mid- and high-frequency reflectionsfrom the walls and ceiling within the room. As sound bounces around the room some frequency ranges can be augmented while others can be canceled out. For example, a voice may sound muddy or harsh depending on what playback frequencies are increased or decreased by the impact of room ambience on the sound produced by the loudspeakers.

So as you plan out your room acoustic treatments, keep in mind that you may need to include some specific treatment approaches to address your loudspeaker playback performance. “Boominess” can often be addressed by placing some thick sound absorbing foam behind the loudspeakers, between the speakers and the wall, or placing thick wedge-shaped sound absorbing foam pieces in the corners. Mid- and high-frequency reflections problems can likely be addressed through general acoustic absorption and diffusion treatments placed on side and rear walls. Or you can try moving your monitors (and desktop that you use for editing) to different locations throughout the room to find the location that is best suited for monitoring loudspeaker placement.

Or if all else fails, you can always use professional-quality headphones during the editing process to remove the impact of room ambience colorization of your playback, but this may become uncomfortable during longer editing sessions.

But keep in mind that this problem is typically more of an issue with systems used to edit music recordings, because music producers listen to their programs at a higher volume level, and the musical programs themselves have many more complex elements that need to be adjusted and carefully balanced (i.e., various instruments and voices) during the editing and mixing process. Editing a single voiceover track is less complex, and therefore less affected by room ambiance and loudspeaker placement. And in most cases, you will also typically not play back your voiceover at a volume level where this will become a major issue.

 

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