CTS-D 2
pressure; electromagnetic
A dynamic microphone is a [...]-sensitive microphone with a moving-coil design that transduces sound into electricity using [...] principles.
1
A gain of [...].0 refers to a matte white screen surface that does not absorb or channel light, is uniformly reflective, and can be seen from all directions.
reflective
A glass-beaded screen that has a gain reading of 1.3 or 1.5 is highly [...], less uniformly [...], and has more hot spotting.
10
A good clue that a device's level might be −[...] dBV is the use of the phono or RCA connector.
interfere
Moreover, when a projector is in the same space as its users, people such as presenters or instructors, especially, can [...] with the image by walking in front of the projected light (which, frankly, can also be annoying for the presenter).
16:9
high-definition (HD) video
1
0 dBV is equivalent to [...] volt.
775
0 dBu is equivalent to 0.[...] volts .
horizontally
Human vision is oriented [...].
94
One pascal is equal to [...] dB SPL.
90
Therefore, the total good viewing area is [...] degrees.
6
The "[...] dB down" point is typical for defining a loudspeaker's coverage pattern.
image
When designing a video system, your first task is to determine [...] specifications.
contrast ratios
7:1, 15:1, 50:1, 80:1
63 in (1594 mm)
A 16:9 screen will be installed in a lecture hall. The screen's diagonal is 72 in (1,829 mm). What is its width?
lavalier
A [...] (also called a lav or lapel microphone) is attached directly to clothing, such as a necktie or lapel (pictured in the following illustration).
10
A [...] dB change is required for listeners to perceive subjectively a sound that is twice or one-half as loud as it was before.
1
A [...] decibel (dB) change is the smallest perceptible change noticeable.
spot
A [...] meter (sometimes called a luminance meter) measures the light that is reflected off an object back to the meter and can vary based upon the attributes of the subject being measured.
shotgun
A [...] microphone is a long, cylindrical, highly sensitive, unidirectional microphone used to pick up sound from a great distance.
hot
A [...] spot is the part of a displayed image that is unevenly illuminated, usually appearing as a bright area in the center.
Display size
A conference room requires videoconferencing and AV presentation capabilities. Which design elements are defined by the architectural dimensions and orientation of the room?
resolution
A display device has a "native" [...], which is the [...] that is optimized for the display.
quantity; constant
A lumen is a measure of the light [...] emitted from a [...] light source across 1 square meter.
audience
A major part of designing an AV-enabled room is ensuring that an [...] can see what's presented while seated in the good viewing area.
1.0
A matte white screen surface has a gain of ___
screen
A projection [...] is a passive device and does not have the capacity to amplify or create brightness.
application
The choice to design a videowall is driven by the [...].
EAD
The farthest distance at which they can still communicate clearly is the [...].
10
Again, [...].78 lux is equal to 1 footcandle.
speech
Also note that your ears' sensitivity is where normal [...] frequencies are located, 500 to 4,000 Hz.
manufacturer
Always refer to the [...] of the screen to identify which side is designed to face the audience.
reflected
Ambient light that is not on-axis between the projector and viewer (light from exit signs, hallways, windows, etc.) is [...] away from the viewer.
optotype
An [...] is a character used to assess a person's visual acuity.
sensitivity
Another important performance criterion that characterizes a microphone is its [...] specification.
gain
As [...] increases, so does hot spotting.
10
As noted earlier, for a speech-only sound reinforcement system, [...] dB of headroom is appropriate.
drop
Designers should specify whether extra [...] is required to compensate for ceiling or projection height.
interference
Because mic level operates at only a few millivolts, it is prone to [...].
same
Because most front screens are matte white finish, it is fairly easy to assume that the ambient light reading near the screen location will be nearly the [...] as a measurement of black at the screen.
contrast
Because projected images are often the centerpiece of AV systems, the image [...] ratio is one of the most important criteria.
lamp
Because the light is spread across the screen, you need to consolidate the light to the projector [...].
Examine the AV designs of other facilities
Benchmarking is a process by which AV designers and clients:
The area a person needs to turn around without disturbing other people
Circulation space is ___
4:3, 16:9
Common video aspect ratios
30 degrees
In a sightline study, you can determine the minimum distance between the nearest viewer and a display by drawing a sightline from the top of the projected image to the eye of the closest viewer at what angle?
acrylic
Diffusion screen material for rear projection is usually rigid [...], glass, or vinyl fabric.
resolution; acuity
Displays are characterized by [...]; the human eye is characterized by [...].
lens; screen
Distance is the distance from the front of the [...] to the closest point on the [...].
21
Each 32 by 24 in (813 × 610 mm) screen is 800 by 600 pixels and displays [...] rows of information.
line
Electrical signal level The goal is to have a [...]-level signal after the preamplification.
45
Figure 5-9 A good viewing area is [...] degrees off-axis in either direction.
direct
Footcandle (fc) is also a unit of measurement for [...] light.
20
For a music reinforcement system, as much as [...] dB of headroom is needed to avoid clipping musical peaks.
10; 20
For a speech application, the recommended value is [...] dB; for program audio, it's as much as [...] dB.
60; 65
For a typical speech reinforcement system, that level is around [...] to [...] dB SPL.
illuminance
For designers, [...] is expressed as IL-luminance or Incident Light-Luminance.
95
For example, a change from 85 dB SPL to [...] dB SPL is perceived to be twice as loud.
75; 11
For example, if a line of text is 3 in ([...] mm) high, the maximum viewing distance for this font is about 37.5 feet (about [...].5 meters).
4
For example, the log of 10,000 is [...], and the log of 0.0001 is −[...].
brightness
For example, when shining a flashlight on a wall, the reflected spot is not of uniform [...].
00002
For sound pressure, the reference level is the threshold of human hearing at 1 kHz, 0.[...] Pa.
10
For speech applications, [...] dB is considered adequate.
8; inspect
For the viewing task ratio, which is based on levels of detail, use a factor of [...] when viewers will observe content (general viewing), use 6 when viewers will [...] content with clues (reading with clues), and use 4 when the viewers will [...] content without clues ([...]ion).
unit
For this reason, the decibel is dimensionless and cannot be properly called a [...].
Text height × 150 = maximum distance from the screen
Formula for determining whether onscreen text is legible.
less
Front projection is also [...] costly and easier to install than rear projection.
potential; acoustic
Gain before feedback is frequently referred to as [...] [...] gain, which you will learn about later in this chapter.
design
Gain before feedback is largely a [...] issue.
task
Generally, the lux measurement is taken at a [...] area, which could be a video screen, note-taking location, or reading area.
screen
Hot spotting is caused by the properties of the [...] surface.
front; off
Hot spotting is one of the trade-[...]s for screen gain in [...]-projection screens and some rear-projection screens and is most noticeable when viewing a projected image [...]-axis.
36 point
If a font height is 2 in (50 mm), the screen height is 60 in (1,525 mm), and screen resolution is 1080 pixels high, what is the font size in pixels?
back
If a projector is mounted at a height equal to the top center of the screen, the light would be directed [...] at the audience in a downward direction.
stretch
If a source image is a different height or width than the display, the display's scaler may [...] the image or create unsightly borders.
great
If the difference between black and white is not [...] enough, the resulting images are difficult to see and text is difficult to read.
behind
If there is an obstruction in the center, such as a table, designers should use the first available position [...] the obstruction.
113.6 to 1022.7 lux
If you have a projector that is 2500 ANSI lumens on a 5.5 m 2 standard matte white screen, what should be the limits of the task lighting? Note that the projector specification is derated by 25 percent.
23; 316
In a professional audio system, line level is about 1.[...] volts (+4 dBu); consumer line level is 0.[...] V (−10 dBV).
candela
In fact, you can use the [...] to measure the amount of light that is reflected off any surface.
less
In general, front projection requires [...] floor space than rear projection because the projector is often placed in the audience area.
brightness
Luminance is the quantitative measure of the [...] of a light source or illuminated surface, measured in candelas per meter squared (cd/m2).
metric
Lux is usually associated with [...] measurements.
decibel
In other words, a [...] is a measurement of how much change a person will actually perceive as a linear value changes.
10
In technical terms, a decibel is a base-[...] logarithmic ratio between two values.
contrast
In the AV industry, the level of [...] between black and white in a displayed image is critical.
luminance
In video, [...] (Y) is the monochromatic, or black and white, picture information.
60
InfoComm states no less than 1× the screen width, which closely matches your eyes' viewing angle (approximately [...] degrees for color discrimination), is too close.
circles
It is a flat glass or acrylic lens in which the curvature of a normal lens surface has been collapsed, creating concentric [...] on the lens surface.
passes
It is a transmissive system, in which light [...] through the screen toward the viewer.
headroom
It is important to have enough [...] to handle momentary performance boosts.
omnidirectional
It is important to keep in mind that the PAG formula assumes you're using an [...] microphone and loudspeaker.
45
It is typically defined as any point within [...] degrees to the left or right from the straight-on axis (see Figure 5-9).
lighting
Keep in mind that the luminance for a camera is not the same as for [...].
50
Lamp life is defined as the time it takes for a lamp to reach [...] percent of its initial light output.
0
Line level on the other hand, should be between [...] and +4 dBu for pro audio. • The consumer audio level is −1[...] dBV ([...].316 V).
brightness
Luminance is the photometric quantity most closely associated with a person's perception of [...].
1
Meanwhile, dBV indicates that the reference level is a voltage of [...] V.
low
Mic level is a [...]-level signal— only a few millivolts (abbreviated as mV to express one-thousandth of a volt).
50; dBu
Microphone level, which is typically measured in [...], should be −60 to −[...] [...], well below the zero reference of 0.775 volts for the [...].
70; 75
Normal face-to-face speech communication is about 60 to 65 dB SPL, but most speech reinforcement systems operate between [...] and [...] dB SPL.
throw
Notice that the screen width stays the same, but the [...] ratio determines how far away the projector is from the screen.
lux
One [...] is equal to 1 lumen per square meter, or 0.093 footcandles.
flat
One of the advantages of a videowall designed to incorporate [...]-panel monitors, for example, is that it requires less physical space than a videowall that incorporates projection technology or video cubes, which are often deeper than [...] panels.
polar
One of the characteristics to consider when selecting a microphone is its [...] response or pickup pattern.
lamp
Operating hour figures are not displayed because each [...] is specified differently.
Lower than their standard line of sight
People view objects more comfortably when the objects are located ___
4; 775; 23
Pro-audio line level is often expressed as +[...] dBu, which expresses a voltage above the 0.[...] reference point, or 1.[...] volts.
acuity; output
Put another way, visual [...] is what an individual set of eyes can see, but screen resolution is what an electronic display can [...].
translucent
Rear-screen projection describes a presentation system in which the image is projected from behind and through a [...] screen, toward the audience on the opposite side.
ambient
Reducing [...] light at the screen location is the most important element of creating a good contrast ratio for the projected image.
one
Remember that the sum of the parts will need to appear as [...] display when all is said and d[...], so the reds on [...] screen need to match the reds on another.
angular
Resolution acuity is measured in terms of the smallest [...] separation between two stimuli that can still be seen as separate.
loudness
SPL is expressed in decibels to correlate with the human perception of changes in [...].
brighter
Screen gain is the ability of a screen to redirect projected light to make the image appear [...] within the viewer area.
headroom
System [...] is the difference between the audio system's typical operation level and the maximum level the system can attain.
Technology managers
Technical end users are sometimes referred to as:
A
The [...]-weighting, therefore, is useful in low-listening-level situations, roughly 20 to 55 dB SPL.
lumens
The amount of light energy delivered to the screen is measured in [...].
hot
The brightest area in that spot is the [...] spot.
316
The consumer line level is often expressed as −10 dBV, or [...] millivolts.
luminance; darkest
The contrast ratio of a display system is the ratio of the [...] of the brightest color (white) to that of the [...] color (black).
ambient
The contrast ratio of a front-projection system is largely dependent on the AV designer's ability to control [...] light in a space, but the brightness of the projector and the screen material are also important.
12
The font height is [...] mm, and the pixel count is [...].
D0
The formula for NAG is as follows: NAG = 20log([...]/EAD)
ImageHeight / Distance from the farthest viewer to the image = 1 / Viewing task ratio (distance)
The formula for determining image height based on a viewing task:
Distance = Screen width of the projected image * Throw ratio
The formula for estimating throw distance from the front of the lens to the closest point on the screen:
Lumens = Ambient light level * Required contrast ratio * Screen area * Gain of the screen (assume a screen gain of 1 unless otherwise noted) / Projector derating value (assume a derating value of 0.75 unless otherwise noted)
The formula for required projector brightness is:
Task LightUpper = [(Lumens / Area of the screen) * Screen gain * (1 - projector derating percentage)] * 3
The formulas for task-light upper levels
angle
The light is reflected at the same [...], it strikes the screen but on the other side of the screen's axis.
10
The logarithm of a number is how many times the number [...] must be multiplied by itself to get a certain value.
45
The maximum acceptable viewing angle is [...] degrees from the far edge of the screen.
Fresnel
The most common is a two-lens system, in which the lens that faces the projector is a [...] lens.
decibel
The most common unit of measurement for sound is the [...].
three
The objective is to have a task-light level that is in a range of plus or minus [...] times the white level, in lux.
Snellen
The perception of five out of six letters (or a similar ratio) is called the [...] fraction.
vertical
The second lens, molded to the other side of the acetate or to another sheet, is a [...] lenticular lens.
Farthest viewer distance = Image height * Viewing task
The simple image height formula wheel
28 feet
The total length of a measurement from a U.S. customary scaled drawing of 1/8 inch is 3.5 inches. What is the length of the real object?
5 meters
The total length of a measurement from a metric (SI) scaled drawing of 1:50 is 100 mm. What is the actual length?
background
The viewer is able to recognize the images on a screen and can separate text or the main image from the [...] under typical lighting conditions for the viewing environment.
mismatch
The worst-case scenario is a [...] between a screen and projector and a [...] from image to projector.
resolution
There are several different kinds of acuity, including [...] acuity, which is the ability to detect that there are two stimuli, rather than one, in a visual field.
light; darker
This is because a white screen can only get brighter when [...] is applied, but the screen can never become [...].
sensitivity
This rating is called a [...] specification, and it defines the loudspeaker's acoustic output signal level, given a reference input level.
clues
This viewing task—a combination of words and images—is known as reading with [...].
close
To do this, you need to know the position of the audience, and the first question you need to ask is, "How [...] is too [...]?
15
Typically, a [...] dB S/N ratio may suffice in situations where considerable noise is expected, such as live sports where there are spectators.
rougher
Typically, the projector side is smooth and clear, while the audience side is [...].
smallest
Usually—but not always—recognition acuity is measured in terms of the angular dimension of the [...] target that can be discriminated.
acuity
Visual [...] is an eye's ability to discern fine details.
screen
With front projection, the image is viewed from the same side of the [...] as the projector's location.
Identifying the intended use of a space
What is the primary goal of a needs analysis?
5 footcandles (50 lux)
What is the recommended (highest) ambient lighting level illuminating a front-projection screen within a videoconferencing space?
Detail drawing
What type of drawing would you use to find out exactly how the projector should be mounted to the ceiling?
ambient
When calculating projector brightness, your black level is a measurement of the [...] light at the screen.
sensitive
When choosing a loudspeaker, you must verify that the loudspeaker is [...] enough to boost the sound signal with enough.
10 to 20 degrees
When considering viewers' visual field along a horizontal plane, people can recognize words, fine details, and color at what angle from the standard line of sight?
color
When designing a videowall, it is important to specify displays that can be [...] matched in applications where one or few images will span multiple screens.
height
When determining text size, your design goal is to create a text [...] that is easy to read and won't cause eye strain or fatigue.
loudspeakers
When distributing [...], the goal is to place them in a strategic pattern to create a uniform sound source.
brightness
When someone is seated within the good viewing area, a screen should provide uniform [...] over the entire image area, with no dim areas or hot spots.
bright
When you select a projector, you need to make sure the one you choose is [...] enough for your viewing environment.
high
Where ambient light is too great and can't be adequately controlled using curtains or other solutions, a [...]-gain screen is often used.
OFOI (which means "owner furnish, owner installed")
Which abbreviation on a drawing tells you that you will not need to install a specific display screen?
Providing a sloped or tiered-seating layout
Which can be used to improve sightlines in an auditorium?
C
You may then choose a [...]-weighted filter (indicated by the line marked "[...]" in Figure 6-3), whose curve is far less steep.
fill
Your goal is to have an image [...] the entire screen surface.
Recognition
[...] acuity is the ability to identify correctly a visual target.
Lux
[...] is a contraction of the words luminance and flux.
Illuminance
[...] is light that falls on a surface, measured in footcandles (fc) or lux (lx).
EPR
[...] is the amount of electrical power required at the loudspeaker.
Headroom
[...] is the difference in dB SPL between the peak and average-level performance of an audio system.
Lumens
[...] is the most common measurement term used for describing light output from a projector or lightbulb.
Wref
[...] is the wattage reference value; assume a [...] of 1, unless otherwise noted.
Line
[...] level is the strength of a regular audio signal and is used for all routing and processing between components.
Aspect
[...] ratio is expressed as two whole numbers, separated by a colon (for example, 16:9), or by the decimal equivalent of the implied division (for example, 1.77).
Throw
[...] ratio is the ratio of throw distance to image width.
Sound
[...] reinforcement is the combination of microphones, audio mixers, signal processors, power amplifiers, and loudspeakers that are used to electronically amplify and distribute sound.
Screen
[...] width is the width of the projected image.
Rear
[...]-projection screens are delicate and must be protected if stored onsite while a space is being completed.
Signal; noise
[...]-to-[...] ratio is the ratio, measured in decibels, between the audio (or video) signal and the [...] accompanying the signal.
50:1
contrast ratio for analytical decision making
15:1
contrast ratio for basic decision making
80:1
contrast ratio for full-motion video (home theater)
7:1
contrast ratio for passive viewing
4:3
standard-definition (SD) video
