To sufficiently reproduce the experience of a live, in-person, face-to-face meeting, you must design the environment where you install the TelePresence systems to provide a near-perfect replication of lighting, sound, and ambiance. Careful adherence to the design principles and specifications provided here can result in an experience that is so lifelike, realistic, and free from technological distractions that participants can focus 100 percent of their attention on the people they meet with and the meeting content, and experience most of the same emotional and psychological interactions that occur when people meet face-to-face.
Proper design of a TelePresence environment involves a number of different aspects, each of which by itself is critical to the experience, and some aspects are inter-related and can influence each other. For example, even if the network performs perfectly, an improperly lit room can lead to grainy and pixilated video quality. As another example, if the acoustical behavior of the room, such as the amount of ambient noise and reverberation within the environment, is not controlled, the quality of the audio might sound muffled, reverberant, and even choppy, and the audio detection algorithms used to facilitate switching in multipoint meetings could fail, resulting in false switching to a participant who is not speaking, or a failure to switch to a participant who is speaking. Many of the audio and video issues that at first glance might seem to be attributed to system hardware and software quality or network performance can actually be the result of an improperly designed room environment.
Although the examples that illustrate the principles discussed in this chapter are specific to Cisco TelePresence CTS-3000 and CTS-1000 model systems, most of these principles are adaptive and can be applied to any TelePresence system, regardless of the size, shape, number of screens and cameras, or vendor. As the market introduces new systems, you need to focus on the principles discussed in this chapter and how you can apply them to each type of system.
This chapter covers the following topics:
- Room Dimensions, Shape, and Orientation: Discusses the physical size, shape, and orientation of the room and the location of doors, windows, columns, and furniture within the room.
- Wall, Floor and Ceiling Surfaces: Discusses the recommended colors, patterns, and materials of wall, floor, and ceiling surfaces within the room.
- Lighting and Illumination: Discusses overall illumination considerations and specific lighting requirements and recommendations.
- Acoustics: Discusses the concepts of sound reproduction and the effects of ambient noise and reverberation within the environment and how they are measured.
- HVAC: Discusses the heating, ventilation, and air conditioning (HVAC) requirements and the recommended types and locations of air-conditioning registers within the room.
- Power Requirements: Discusses power consumption requirements for the equipment and participants and the recommended types and locations of electrical receptacles within the room.
- Network Connectivity: Discusses the network connectivity required within the room for the equipment and the participants and the recommended ways to provide network access to the participants.
Room Dimensions, Shape, and Orientation
The primary criteria for selecting a room is to find one that meets the recommended width, depth, and height requirements and is free from obstructions such as pillars and columns. The dimensions also play a critical role in how much lighting is required, how the room appears visually on the screen, and the acoustic properties of the room.
The following sections provide details on each aspect of room dimensions, including width, depth, height, angles, and shapes, such as curved or concaved walls and asymmetric geometries, protruding entrances and vestibules, and the orientation of the TelePresence within the room.
The room needs to be wide enough to comfortably fit the TelePresence system and any peripherals that might be located on its left or right sides, with enough extra space on each side for service personnel to access the back of the system to service it. You might also want extra space for furniture, such as cabinets, coffee tables, couches, sofas, or storage space for extra chairs.
Determining Room Width
To begin, find the width of the TelePresence system itself and add at least 1 foot (30.48 centimeters) on each side to enable service personnel to access the sides and back of the system. The Cisco TelePresence CTS-3000, for example, measures precisely 18-feet (5.486-meters) wide. Adding 1 foot (30.48 centimeters) of access space on each side brings the minimum width to 20 feet (6.096 meters). Figure 8-1 illustrates the minimum room width of a CTS-3000.
Figure 8-1 CTS-3000 minimum room width
The CTS-1000 measures precisely 5.11-feet (1.557-meters) wide. Adding one foot (30.48 centimeters) of access space on each side brings the minimum width to 7.11 feet (2.167 meters). Figure 8-2 illustrates the minimum room width of a CTS-1000.
Figure 8-2 CTS-1000 minimum room width
Factoring in Peripherals
The second step is to factor in any additional peripherals such as auxiliary data displays or document cameras that might be located on the left or right sides of the system. Both the CTS-3000 and CTS-1000 systems support the use of auxiliary LCD displays and document cameras for use with the Auto Collaborate feature. You can often find these optional peripherals on the left or right sides of the system to obtain the total width of the system. Following are some specific examples to illustrate how to approach these considerations.
LCD displays come in different sizes and can be mounted to the ceiling above the TelePresence system; mounted to the wall on the left or right sides of the system; mounted to a vertical stand with a base located to the right or left sides of the system; or placed on a piece of furniture such as a cabinet or cart to the right or left sides of the system. The section "Height Requirements," covers ceiling-mounted scenarios in greater detail. This current section focuses on left- and right-side mounting options. Consider the example of a customer who wants to install a 52-inch (132.08 centimeter) Sharp 525U LCD on the left side of the CTS-3000. The 52 inches is the diagonal measurement of the display. The actual width of this particular display is 49.4 inches (125.476 centimeters). The bezel of the display might be a few inches away from the edge of the TelePresence system and might be mounted on a stand that has a slightly wider base than the actual width of the display. The recommendation in this example would be to round up 6 inches to 12 inches (15.24 centimeters to 30.48 centimeters) to allow for flexibility in the exact placement of the display. Figure 8-3 illustrates this arrangement.
Figure 8-3 CTS-3000 with optional auxiliary LCD display on left side
Document cameras can be mounted within the ceiling or located on a flat surface such as a cabinet or table on the left or right sides of the TelePresence system. For the CTS-3000, the optimal solution is to ceiling-mount the document camera above the table where the participants sit. However, on a CTS-1000 it is popular to use a desktop document camera located off to one side or the other. The Wolfvision VZ-9plus Desktop Visualizer, for example, measures 12.6-inches (32.004-centimeters) wide and would likely be located on a cabinet or table surface at least a few inches larger than the actual base of the visualizer. Figure 8-4 illustrates this arrangement, where the cabinet that the WolfVision camera is sitting on measures 2–feet (60.96-centimeters) in width.
Figure 8-4 CTS-1000 with optional desktop document camera on right side
Factoring in Additional Participants
The third step is to add enough space for participants sitting on the left or right sides of the TelePresence system. This does not apply to the CTS-3000 model system, but on the CTS-1000 it might come into play depending on the orientation of the system within the room. Figure 8-5 illustrates a CTS-1000 with additional seating on the left and right sides of the table.
Figure 8-5 Example of CTS-1000 seating arrangement
The chairs depicted as silhouetted would not be used during an active TelePresence meeting but could be located within the room like this to maximize seating capacity when using the room for non-TelePresence meetings. Interior Design standards specify recommended measurements for the distance from the edge of the table to the back of the participant's chair and from the back of the participant's chair to the wall behind them. These are referred to as the sitting zone and circulation zone, respectively. The recommended sitting zone is 2 feet (60.96 centimeters), and the recommended circulation zone is 3 feet (91.44 centimeters). The circulation zone provides enough distance for people to get in and out of their chairs and for others to circulate behind a seated participant and accounts for wheelchair accessibility. The third measurement to take into consideration is elbow room. Each chair position needs a minimum of 3 feet (91.44 centimeters) of width. For this reason, the recommended table width for a CTS-1000 room is 6 feet (1.828 meters) to comfortably accommodate two participants seated at the table. To accommodate the extra chairs on each side of the table, you need an additional 5 feet (1.524 meters) on both sides of the table, for a total width of 16 feet (4.876 meters).
Factoring in Additional Furniture
The fourth step is to add enough space for any additional furniture, such as cabinetry that might be located along the walls on the left or right sides of the room, extra chairs that might be placed on the side of the room, and so on. Figure 8-6 illustrates a CTS-3000 with cabinets located on the left side of the room and extra chairs stored on the right side of the room.
Figure 8-6 Example of CTS-3000 with cabinets and extra chairs
Understanding Maximum Width Constraints
Now that you are aware of the minimum and recommended width requirements, you need to understand why Cisco specifies a maximum width. In the case of width, the maximum recommendation comes primarily from the acoustic effects of reverberation within the room. When the width of the room is significantly wider than the recommended value, sound traveling through the air might take longer to reflect off of the walls, resulting in high levels of reverberation. Mitigating reverberation caused by excessively wide rooms can occur a number of different ways. Of course, you can always build false walls on the left or right sides to reduce the width of the room, but this is not always necessary. You can usually achieve the desired results simply by placing furniture within the room such as overstuffed chairs or couches, or covering portions of the walls in acoustically dampening materials such as fabrics or oil paintings. The section "Acoustics," later in the chapter, covers reverberation in more detail.
The other negative effect of excessively wide rooms is the amount of light needed to sufficiently cover the entire room in even, well-distributed light. Avoid dark areas and shadows, even if they are not within the view of the cameras. The wider the room, the more light fixtures you need to blanket the room in light. The section "Lighting and Illumination," later in the chapter, covers lighting in greater detail.
Width Requirements Summary
Based on all of the information covered in this section, Table 8-1 summarizes the minimum, recommended, and maximum width requirements for the CTS-3000 and CTS-1000 model systems.
Table 8-1. Minimum, Recommended, and Maximum Room Width for CTS-1000 and CTS-3000
20 feet (6.096 meters)
22 feet (6.7056 meters)
31 feet (9.448 meters)
7.11 feet (2.167 meters)
12 feet (3.657 meters)
20 feet (6.096 meters)
The room should be deep enough to comfortably fit the TelePresence system, with enough extra space behind the participants for people to walk to and from their seats. You might also want extra space for furniture, such as cabinets and sofas, or for extra chairs behind the primary participants.
Determining Room Depth
To begin, find the depth of the TelePresence system and add at least 5 feet (1.524 meters) past the edge of the table to allow for minimum seating and circulation zones. The CTS-3000, for example, measures precisely 10.07 feet (3.069 meters) from the back of the light façade structure to the edge of the table, and recommended specifications dictate that it be installed at least 12 inches (30.48 centimeters) away from the wall to allow service personnel to access the back of the system. Adding 5 feet (1.524 meters) beyond the table edge for the participant's chairs and a circulation zone behind them brings the minimum depth to 16 feet (4.876 meters). Figure 8-7 illustrates the minimum room depth of a CTS-3000.
Figure 8-7 CTS-3000 minimum room depth
The CTS-1000 is a little different because it does not include an integrated table, so the customer must supply a table and must understand how far away the table should be placed from the system. The system itself measures precisely 9 inches (22.86-centimeters) deep and is bolted flush to the wall. But the distance from the camera to the edge of the table is a critical measurement because the camera on the CTS-1000 has a fixed focal length and depth of field. If the participants sit too close to the system, they will appear out of focus, and the vertical angle of the camera to their faces will be skewed, resulting in a distorted view. Likewise, if they sit too far away from the system, they will also be out of focus and will appear smaller than life size. The distance from the camera to the edge of the table should be precisely 8.5 feet (2.59 meters). Adding 5 feet (1.524 meters) beyond the table edge for the participants' chairs and a circulation zone behind them brings the minimum depth to 14.25 feet (4.343 meters). Figure 8-8 illustrates the minimum room depth of a CTS-1000.
Figure 8-8 CTS-1000 minimum room depth
It is common for customers to want to sacrifice the service access zone behind the system or the circulation zone behind the participants' chairs to fit the system into a room that is slightly smaller than the minimum measurements previously specified. For example, many customers have asked if the CTS-3000 can be made to fit within a room that is only 14-feet (4.267 meters) deep, or a CTS-1000 into a room that is only 10-feet (3.048 meters) deep. However, you need to understand several critical aspects that should dissuade you from doing this.
Camera Focal Length and Depth of Field Considerations
First, the focal length and depth of field of the cameras on the CTS-3000 and CTS-1000 model systems are precisely designed to capture a subject that is 8.5 feet to 14.5 feet (2.59 to 4.419 meters) away from the camera. When the wall is too close behind the seated participants, it has two negative side effects:
- The participants appear "painted" onto the wall behind them because you have no depth between them and the wall.
- The wall appears to be "crawling" because it's so close to the camera that it is within the depth of field, and the pattern of the wall surface is visible on camera. Even relatively smooth wall surfaces such as painted gypsum drywall exhibit this behavior.
In addition to these two visual side effects, the walls become marred and scratched over time from participants bumping the backs of their chairs up against them.
Camera Vertical Viewing Angle Considerations
Second, the vertical angle of the camera's field of view is designed to be precisely 7 degrees above the participants' eyes (give or take a degree or two to accommodate different people's heights when seated). This provides optimal vertical eye gaze alignment. On the CTS-3000, it is not possible to sit too close to the camera because it comes with an integrated table, but on the CTS-1000, if the participants sit too close to the system, they appear out of focus and too low on the screen. The natural inclination is for the installer to adjust the vertical angle of the camera slightly downward and pull the focus as far in as it will go to get the participants within the camera's field of view. By angling the camera down, however, you distort the angle of the camera to the subject resulting in a "downward" appearance of the participant on screen and a misalignment of the vertical eye gaze. Figure 8-9 illustrates this concept.
Figure 8-9 CTS-1000 minimum distance from camera
Factoring in Additional Furniture, Seating Capacity, and Wall Adornments Behind the Participants
Now that you understand the absolute minimum depth requirements, consider the space required for optional furniture, extra seating, and wall adornments in the back of the room behind the primary participants. It is highly desirable that customers consider doing this because placing adornments and furniture behind the participants creates a sensation of "depth" on the screen and makes the participants and their environment look as lifelike as possible. You might want to place cabinetry or artwork on the back wall, some couches or overstuffed chairs for decorative purposes, or a combination of both. Figure 8-10 illustrates these concepts.
Figure 8-10 CTS-3000 with cabinet and chairs along back wall
Understanding Maximum Depth Constraints
The last thing to consider is the maximum room depth. As with the maximum width discussed previously, the maximum depth requirement is due primarily to lighting and acoustic considerations, although the lighting consideration is even more severe in this case because the back wall is within the view of the cameras, making shadows and dark areas even more pronounced and undesirable. In addition, objects further than 15 feet (4.572 meters) or so away from the cameras will become increasingly out of focus. Therefore, although it is desirable to have slightly more than the minimum depth to allow for the placement of furniture and artwork to create the sensation of depth in the image, if the room is too deep, this will backfire on you because the objects on the back wall will be completely out of focus.
Depth Requirements Summary
Based on all the preceding information, Table 8-2 summarizes the minimum, recommended, and maximum depth requirements for the CTS-3000 and CTS-1000 model systems.
Table 8-2. Minimum, Recommended, and Maximum Room Depth
16 feet (4.876 meters)
20 feet (6.096 meters)
23 feet (7.01 meters)
14.5 feet (4.419 meters)
16 feet (4.876 meters)
20 feet (6.096 meters)
The ceiling height of the room should be high enough to comfortably fit the TelePresence system and any peripherals that might be located above the system and be within local construction codes for fire suppression systems, suspended light fixtures, and so on. These codes vary by location and the age of the building, but in general, a minimum ceiling height of 8 feet (2.438 meters) is necessary for a TelePresence system.
Determining Room Height
To begin, find the height of the TelePresence system. The CTS-3000, for example, measures precisely 6.76-feet (2.060-meters) high. The CTS-1000 measures precisely 6.48-feet (1.975-meters) high.
Vertical Clearance Considerations for Light Fixtures and Fire Suppression Systems
However, the height of the system is not the critical factor that determines the minimum ceiling height. What's more important are the light fixtures and fire suppression systems. Suspended light fixtures require a minimum vertical clearance from the top of the fixture to the ceiling from which it hangs to achieve optimal reflectivity of the light bouncing off the ceiling, and a minimum vertical clearance from the bottom of the fixture to the tops of people's heads. Even recessed light fixtures have a minimum vertical clearance to throw the light out at the correct angle to provide the optimal coverage pattern. If the ceiling is too low, even the most-expensive recessed light fixture cannot distribute the light properly. The section "Lighting and Illumination," later in the chapter, covers more about light fixtures. Likewise, fire suppression systems have regulations that determine the minimum vertical clearance from the sprinkler head to the equipment and people below it. Consult your local city or state ordinances to understand this better.
Factoring in Vertical Clearance for Peripherals
Second, additional peripherals such as auxiliary data displays or document cameras might be located in the ceiling or suspended from the ceiling. Both the CTS-3000 and CTS-1000 systems support the use of optional LCD displays that you can mount to the ceiling above the system or locate on the right or left sides of the system. If the LCD display is above the system, you need to allow sufficient space between the light façade structure of the system and the ceiling to accommodate the additional overhead display.
Consider the example of a customer who wants to install a 40-inch (101.6-centimeter) NEC 4010-BK LCD display mounted to the ceiling above the CTS-3000. The 40 inches is the diagonal measurement of the display. The actual height of this particular display is 24 inches (60.96 centimeters), and you might want to leave a couple of inches between the bottom bezel of the LCD display and the top edge of the TelePresence system to allow for flexibility in the exact vertical placement of the display. Figure 8-11 illustrates this arrangement.
Figure 8-11 CTS-3000 with optional auxiliary LCD display on top
However, note that in Figure 8-11, if you suspend light fixtures that hang down 24 inches (60.96 centimeters) below the ceiling, they might obstruct the participants' view of the overhead LCD display. Therefore, the ceiling must be high enough so that the angle of the participants' view of the LCD display clears the bottom of the light fixture by a comfortable number of inches (centimeters).
Document cameras, such as LCD displays, can also be mounted from, or within, the ceiling. You can install the Wolfvision VZ-32 Ceiling Visualizer, for example, within a plenum housing recessed within a dropped ceiling, or from a pole in situations where recessing it is not an option. In either case, the Wolfvision VZ-32 Ceiling Visualizer has a minimum height requirement to properly capture a document or other object located on the table surface of the TelePresence system. This is because you must install this particular camera at an 18-degree angle from the area of table it will be capturing. Figure 8-12 illustrates this arrangement.
Figure 8-12 CTS-3000 with optional wolfVision ceiling visualizer
Based on all the preceding information, the recommended ceiling height of a Cisco TelePresence CTS-3000 and CTS-1000 room is 10 to 12 feet (3.048 to 3.657 meters).
Understanding Maximum Height Constraints
The last thing to consider is the maximum ceiling height. Like the maximum width and depth discussed previously, the maximum height is primarily a function of lighting and acoustic considerations. Excessively high ceilings might make it extremely difficult to provide the correct amount of light throughout the room and might cause severe shadowing and dark areas, which must be avoided. Light fixtures take advantage of the reflective properties of the ceiling material (for example, the ceiling tiles of a dropped ceiling reflect light off their surface) to allow light emitted from the fixture to be spread evenly throughout the room. Likewise, the ceiling materials also reflect some percentage of sound. If the sound takes a long time to travel to and from the ceiling, it can result in high levels of reverberation within the room.
The most effective method of mitigating a ceiling that is too high is to install a dropped ceiling to reduce its height. However, if the ceiling is only a few feet too high, to mitigate lighting and acoustic issues, it might be adequate to simply use higher wattage bulbs in your light fixtures and use ceiling tiles that have a high Noise Reduction Coefficient (NRC) Rating to reduce reverberation. The sections "Lighting and Illumination" and "Acoustics" cover more about light fixtures and reverberation. You might need to consult a lighting expert to determine the most optimal type and quantity of light fixtures and bulb wattage required based on the height of your ceiling.
Height Requirements Summary
Based on all of the preceding information, Table 8-3 summarizes the minimum, recommended, and maximum height requirements for the CTS-3000 and CTS-1000 model systems.
Table 8-3. Minimum, Recommended, and Maximum Room Height
8 feet (2.438 meters)
10 feet (3.048 meters)
12 to 14 feet (3.657 to 4.267 meters)
Angles, Shape, and Orientation
Rooms are not always square or rectangular in shape, often have protruding entrances, vestibules, or columns, and the walls can be curved or concaved. Walls and ceilings can also be vertically or horizontally asymmetrical.
These types of geometric patterns can be good or bad, depending on the orientation of the TelePresence system within the room. Consider the three primary factors:
- How angles and shapes within the field of view of the camera appear on screen
- Whether obstructions, such as protruding entrances and columns, interfere with the location of the TelePresence system within the room
- How the acoustics might be affected by curved, concaved, or asymmetric wall and ceiling angles
Considering the Effects of Protruding Walls
Figure 8-13 CTS-3000 horizontal field of view
Figure 8-14 CTS-3000 vertical field of view
From a top-down perspective (horizontal field of view), the cameras capture a portion of the side walls and the entire back of the room. From the side perspective (vertical field of view), the cameras capture everything from just above the participants' heads all the way down to the baseboards and even the floor, depending on how far away the back wall is from the cameras. Refer back to the "Depth Requirements" section in this chapter for guidance on how deep the room should be.
The point of these illustrations is to highlight that everything within the camera's field of view will show up on screen. Vertical and horizontal lines and shapes on the walls and floor can appear on camera and be distracting; inverted corners can cause undesirable shadowing because light from the ceiling fixtures might not reach it; and protruding walls can interfere with the placement of the system.
For example, consider what would happen if a protruding wall or column were placed within the room. Figure 8-15 illustrates this arrangement.
Figure 8-15 CTS-3000 with protruding wall within the horizontal field of view
Not only would this protruding wall become an obstacle for the two participants seated on the right side of the system and interfere with the circulation zone behind them, but also the vertical edges of the wall would appear on camera and could be distracting. Most important, in this particular example, the corners where the back and side walls meet the protruding wall will likely be darker than the other wall surfaces because light from the ceiling fixtures will not illuminate them as well. Depending on the dimensions of the room, it might be possible to reorient the system to avoid this situation. Figure 8-16 illustrates one example of how this can be achieved, provided that the walls are wide enough the fit the system and depending on the location of the door.
Figure 8-16 CTS-3000 reoriented to eliminate protruding wall
This example arrangement sacrifices access to the back of the system from the left side of the system to place the system as close to the middle of the room as possible, but access is still available from the right side, so it might be the best compromise in this example. This arrangement also leaves no room on the left or right sides of the system for optional peripherals such as auxiliary LCD displays; however, if the ceiling is high enough, the customer might opt to mount the auxiliary LCD display from the ceiling above the system. Also, depending on the location of the door, this arrangement might not be possible at all, or the door would need to be moved to an alternative location. The customer must weigh the pros and cons of these trade-offs. The best solution might be to simply find a different room or investigate how much it would cost to have the protruding wall removed.
Considering the Effects of Curved and Concave Walls
Next, consider the effect of curved and concaved wall surfaces. Depending on their shape and the orientation of the system within the room, curved and concaved wall surfaces can produce unfavorable acoustic side effects because sound reverberating off their surfaces could converge at a certain place within the room. Figure 8-17 illustrates an example of this effect.
Figure 8-17 CTS-3000 with concaved wall surfaces
The arrows within the diagram illustrate how sound emanating from the system reflects off the walls in such a way that it converges in the center of the room. Reverberation levels in the center are higher than on the outsides, which can throw off the echo-cancellation algorithms of the system and cause a negative acoustic experience for the participants. Simple tactics for reducing this effect include placing furniture or hanging acoustic-dampening material, such as fabrics or oil paintings, on or near the back wall to either absorb the sound or cause it to reflect in a different direction. The section "Acoustics" later in the chapter, covers reverberation in greater detail.
Considering the Effects of Asymmetric Wall and Ceiling Angles
Finally, consider the effect of asymmetric wall and ceiling angles. Walls can be asymmetrical both vertically (the angle of the wall from floor to ceiling is not straight up and down) or horizontally (the length of the wall goes in toward the room or out away from the room at an angle). Ceilings can also be at asymmetrical angles. Figures 8-18 and 8-19 illustrate asymmetric wall surfaces from a top-down and side perspective.
Figure 8-18 CTS-3000 with horizontally asymmetric wall surfaces
Figure 8-19 CTS-3000 with vertically asymmetric wall surfaces
These types of geometries can actually have a positive effect on the acoustic properties of the room because sound emanating from the system reflects in different directions. However, the wall surfaces that appear within the camera's field of view might be at odd angles and end up being a distraction. You might also find it more difficult to achieve a consistent level of illumination along the wall surfaces because of the odd-shaped corners.
Doors and Windows
The primary goal is to keep all doors and windows outside of the view of the cameras. However, this is not always possible and should not be considered a strict requirement. Doors should ideally be located so as to maximize the circulation zone around participants' chairs and should not be located behind or on the sides of the system. Figure 8-20 illustrates the recommended door locations on a CTS-3000.
Figure 8-20 CTS-3000 recommended door locations
The ideal arrangement is to have a vestibule, although this is seldom feasible given standard conference room dimensions. Figure 8-21 illustrates an example vestibule arrangement.
Figure 8-21 CTS-3000 with vestibule entry way
Remember that any surface within the view of the cameras should be made of a material that looks good on camera and complements the décor of the room. Therefore, steel and wood grain doors should be avoided, particularly if they are within the view of the cameras. Painted surfaces free of any distracting textures are the best choice.
Door jambs should be sealed to block ambient sound from outside the room from leaking through the cracks in the door jamb or the space underneath the door. The section "Acoustics," later in the chapter, covers ambient noise in greater detail.
Cover windows, regardless of their location, to block out all sunlight and reduce acoustic reverberation. Windows that face the interior of the building and do not allow any sunlight into the room do not necessarily need to be covered, although you might still want to do so for purposes of acoustics and aesthetics. When windows are within the view of the cameras, special care needs to be taken to choose a window covering that looks good on camera. Horizontal and vertical blinds are not recommended. Loose, billowy drapes and curtains are also not the best choice. Drapes made from a straight or taut material are the most suitable and should ideally be a solid color, free of any distracting patterns or textures, look good on camera, and complement the décor of the room.