Making Audiovisual Systems Easy to Use

As technology evolves it seems that it becomes harder to operate and control. Manufacturers are giving us features and options that while useful at some level are not needed most of the time. Control systems are what make systems easier to use.

Complicated Systems
In the project described below the control system was what allowed the Clerk of the Board to run the meeting from a parliamentarian point of view and from a presentation point of view. To run the meeting three people had the ability to control items; the Clerk, the production operator in the control room, and the Chair of the session. All of these individuals had a touch sensitive control panel located at their seat. The Clerk and the Production Operator had the same controls. They typically would use the control system to:

– Power the system on and off
– Select the proper meeting set up; the system could be used for meetings from 7 to 39 depending on the governing body that was using the facility.
– Board Member’s Page with list of Board Member’s associated with their seat at the dais. The clerk has the ability to edit/add/remove names for board members. Once set these board member names will be stored for future use. The Clerk has the ability to mark a board member absent or non-voting for that session. Once set the board member assignments will be used for subsequent voting and vote tallying pages.
– Display control with controls to turn on/off the video projection equipment and determine what source is displayed on the Video Projection Screens.
– Lighting and volume control. – Audio and Video conference system control.
– Presenter Timer controls the public speaker’s allotted time and allotted warning time in one-minute increments. The Clerk and Session Chairperson have the ability to stop/start/pause the allotted time. These timer settings control 3 lights at the podium to alert the presenter of their status.
– The voting module uses the currently selected Board member’s page along with columns for their vote. When the Clerk initiates voting this tally area will indicate voting is occurring and will provides indication which member has cast their vote. It does not show their actual vote until the clerk selects the Vote Tally button. At that point the actual votes will be displayed by the member’s name on all of the video projectors and monitors.
– Speaker Queue Page with buttons indicating who has selected their request to speak button and the order in which that was selected. The Clerk or the Session Chairperson has the ability to select the next speaker which will un-mute their microphone or to directly select anyone on the list which will cause their name to move to the top of the list and un-mute their microphone.

The Chair of the Session has the following limited control.
– Speaker Queue Page.
– The volume and mute controls for each board member’s microphone.
– The chairperson has the ability to pass the chair position to any other member at the dais at which point their panel will assume the chair functions and the previous Chair’s panel will revert to a regular member panel, the Chair’s panel functions can only be passed, they cannot be taken. When the system is turned on a selected default position is selected as chair.

All in all a complicated system that could only be handled with a custom programmed control system.

Simple Systems
 At the other end of the spectrum we are seeing simplified systems of push buttons on a wall panel in many higher education and some corporate training rooms. The wall panel sends the commands to the display device to select the source, raise and lower the volume, dim the lights, lower the projection screen, etc. at a fraction of the cost that existed a few years ago.

The Solution
The common point to both extremes is to have a clear understanding of what needs to be controlled, select the correct system either complicated or simple, but most importantly clearly label buttons with words and terms that the end user understands.

As technology evolves it seems that it becomes harder to operate and control. Manufacturers are giving us features and options that while useful at some level are not needed most of the time. Control systems are what make systems easier to use. Complicated Systems In the project described below the control system was what allowed… Read more »

Noise Criteria (NC) vs. Room Criteria (RC)

Quite often we are asked why does Thorburn Associates Inc. use Noise Criteria (NC) as opposed to Room Criteria (RC) during our mechanical system noise calculations. Both NC and RC are measures of mechanical system noise in a room. Noise Criteria curves were defined in 1957, by Leo Beranek of the Boston based Acoustical Consulting firm of BBN. Room Criteria curves were first proposed by Warren Blazier for the American Society of Heating Refrigeration and Air-Conditioning Engineers (ASHRAE) in 1981.

Both sets of Criteria plot the noise level measured in a room against a set of curves across the different standard octave bands that are used in our acoustical work. For Noise Criteria we plot the octave band sound pressure levels in 8 bands and then select the highest curve that is crossed to come up with a single number to report. The Noise Criteria curve very closely resembles equal loudness curves that correspond to our sensitivity to higher frequency tones and our lack of sensitivity to lower frequency tones.

For Room Criteria we plot the sound pressure levels in the same 8 bands, and we also look at the curve, but now we must add a subjective decision to the curve to report the level. The RC curve is a straight line with a slope of 5 decibels per octave (in English, it does not correspond to how we hear).

So the short answer to the original question is – we use NC whenever we can because it does not require a “subjective” decision and it corresponds more closely to how a person hears.

Quite often we are asked why does Thorburn Associates Inc. use Noise Criteria (NC) as opposed to Room Criteria (RC) during our mechanical system noise calculations. Both NC and RC are measures of mechanical system noise in a room. Noise Criteria curves were defined in 1957, by Leo Beranek of the Boston based Acoustical Consulting… Read more »

Loudspeaker Technology

Over the past few years, thanks to digital signal processing, audio designers have been able to develop arrays of loudspeakers. By grouping loudspeaker boxes with special signal processing the coverage area can be changed and controlled. This type of design can help minimize reflections off of walls at a concert or to direct sound to a specific point in a stadium for sporting events. The drawback is that these arrays are very large and do not easily fit into rooms smaller than 5000 seats or so. Recently, loudspeaker manufacturer EAW has released the new Digitally Steerable Array, or DSA™ Series designed for use in small to mid-sized permanent installation applications. The DSA Series permits the steering and aiming of a loudspeaker’s output and adapts it to applications where a column array loudspeaker design would be beneficial.

In a DSA Series loudspeaker, each driver enjoys its own individual amplification and digital signal processing (DSP) that is controlled using EAW’s DSA Pilot software program. Users can vary the vertical coverage pattern from 15 to 120 degrees wide as well as aim the coverage ±30 degrees. Each DSA loudspeaker delivers a fixed horizontal coverage pattern of 120 degrees. This wide-angled coverage allows for wide horizontal spacing between DSA modules in an installation.

In addition, the DSA loudspeaker has internal power amplification and 16 channels of complex digital signal processing that includes delay, equalization and limiting. Users only need to connect AC power, audio signal, and network communication cables. While it is not something we will use in every job, it is a product that definitely fills a niche when space is at an absolute premium.

Over the past few years, thanks to digital signal processing, audio designers have been able to develop arrays of loudspeakers. By grouping loudspeaker boxes with special signal processing the coverage area can be changed and controlled. This type of design can help minimize reflections off of walls at a concert or to direct sound to… Read more »

UNCA Highsmith Student Center

University of North Carolina – Asheville, Highsmith Student Center, Asheville, NC
Architect: Lee Nichols Clark Patterson

Located in Asheville, NC is the new 73,920 square foot Student Center for the University of North Carolina – Asheville. The project is a renovation and expansion of the old student center originally built in the early 1980s. The new design is very open, with high ceilings, and is filled with natural light. Most of the rooms are open to the structure above, to a height of up to 30 feet in divisible meeting rooms and lounges. The expanded student center will house offices for the student government, bookstore, food court, pub, post office, and university newspaper to name a few. The project is expected to be completed by the summer of 2004.

Thorburn Associates is pleased to be providing audiovisual consulting and wireless network infrastructure for this “bar raising” project. Key spaces include a meeting room divisible into 4 separate rooms; 3 additional stand alone meeting rooms; 2 conference rooms; a Pub for live performances (small ensembles, stand-up comedy and open microphone style acts) and a Multipurpose room equipped with a 7.1 surround sound system. Throughout the facility a digital bulletin signage system will be utilized.

University of North Carolina – Asheville, Highsmith Student Center, Asheville, NC Architect: Lee Nichols Clark Patterson Located in Asheville, NC is the new 73,920 square foot Student Center for the University of North Carolina – Asheville. The project is a renovation and expansion of the old student center originally built in the early 1980s. The… Read more »

Presenting the Perfect Picture

Think about the last time you were at a presentation where it was difficult to see the images being displayed. While there was nothing wrong with the presentation equipment or the quality of the installation, something was still not quite right. That something detracted from the presenter’s ability to communicate their message. When we are asked to look at spaces with this problem, we find it is almost always the size of the image on the projection screen. The ability to see the presenter and their material is critical for a successful presentation environment. This includes addressing the size of the image on the projection screen or monitor, proper viewing angles, and careful planning and design of the display location.

Image Size

The most common problem here is that the image is too small. The standard rule of thumb for sizing images is the four six eight (4-6-8) rule. This means the furthest viewer should be no more than 4, 6, or 8 times the image height away, depending on the material being viewed. Conversely, if you know the furthest viewer is 60 feet from the image then the screen should be 15, 10 or 7.5 feet high respectively based on the 4-6-8 rule.

The 4 factor is used when we need to inspect the image, such as a CAD drawing or a fine detailed map that requires close inspection. The 6 factor is used for reading or detailed viewing, such as spreadsheets or text with images. This is the most common size for presentation environments. The 8 factor is used for general viewing, watching a movie or images with few words. The 4-6-8 rule is derived from studies showing the minimum symbol height (i.e. text) the human eye can resolve along with a factor to account for viewers of varying visual acuity and varying viewing angles. No matter what the material, if you are doing a presentation, the 4-6-8 rule can be applied. Once the image height is known, the aspect ratio determines the screen width. There are many different aspect ratios for displays, the two most common aspect ratios we find are for video and HDTV. For traditional video displays, the aspect ratio is 4:3 (i.e. 4 units wide by 3 units high or 1.33); for HDTV displays, the aspect ratio is 16:9 (i.e. 16 units wide by 9 units high or 1.78). So the 10 foot high image mentioned earlier would be 13.3 feet wide for a traditional video display and 17.8 feet wide for an HDTV display.

Viewing Angle

The preferred viewing angle has the audience no more than 45 degrees to each side of the center of the image, or within a 90 degree “viewing cone” centered on the image. This cone can be expanded to 45 degrees off the edge of the image for acceptable viewing areas. Using the aspect ratio above, you now know the width of the image and can determine the acceptable viewing area. So between the 4-6-8 rule and the viewing cone we have established that the acceptable and preferred viewing areas in any room have a direct relationship to the size of the image.

Screen Location

We know how large the image should be but how big should the screen be? How high should it be off the floor? How far below the ceiling? Well, all of this depends on what or who may be blocking your view. If a short viewer can be seated behind a tall person, we have to either raise the screen, staggering the seating, or if in an auditorium, slope the floor. When you arrange the seats to create a greater distance between the viewer and the head directly in front of the viewer, you can lower the minimum height of the projection screen. Using a sectional drawing with tops of heads and eye locations drawn in (average top of head at four feet and eye at 3 feet 6 inches), you can quickly determine how high the projection screen needs to be off the floor to allow everyone a good view of the screen. In the end the solution will be a compromise, but we have found for most spaces the bottom of the screen is at 42 inches above the floor, and the top of the screen is no closer than 6 inches to the ceiling.

Ultimately there is no perfect solution to every presentation environment. But it is important to think about the presentation space and create a design that allows everyone to see and hear the presenter and their material with the least amount of difficulty. Combining a well-planned room with a good technical design equals a great presentation environment every time.

 

Think about the last time you were at a presentation where it was difficult to see the images being displayed. While there was nothing wrong with the presentation equipment or the quality of the installation, something was still not quite right. That something detracted from the presenter’s ability to communicate their message. When we are… Read more »

Speech Privacy Within Hospitals Meeting the New HIPAA Standards

Confidentiality between a patient and the health provider is one of the basic principles of modern health care. Without confidentiality, the effectiveness of the health care system decreases, due to patient fear of having their medical records revealed and possibly used against them.

In 1996, Congress passed the Health Insurance Portability and Accountability Act (HIPAA) with the final wording of the Act being approved last year. The Act is designed to increase the patient’s privacy and ease of obtaining their medical records. The US Department of Health and Human Services is responsible for regulating the Act. Violations of the Act can be punished by fines and/or criminal sanctions as well as be subject to civil lawsuits.

Meeting the HIPAA Standards requires specialized computer systems and staff training, among other changes to the hospital operations to protect the patient’s medical records. It also places additional consideration on the architectural design of the medical facility. There is now a legal obligation to provide speech privacy between the patient and the health care provider, especially in key areas, such as in Treatment/Exam rooms, and in Admission areas.

Speech privacy between two spaces can be measured using methodologies such as the Articulation Index (AI). The AI is a measure of speech intelligibility, with a value from 0 to 1. A “1” indicates perfect speech intelligibility, while a “0” indicates perfect speech privacy. Typically, AI ratings of 0.2 or less are appropriate for medical system speech privacy.

Providing “confidential” speech privacy in medical environments demands that careful attention be paid to many aspects of the design. The common walls between patient consultation areas and the rest of the hospital must be constructed to sufficiently reduce sound transfer between the spaces. Plumbing and electrical penetrations in the common walls can reduce the sound isolation and must be addressed. Suitable doors must be selected and properly gasketed. The HVAC system must also be designed to prevent cross-talk and other ductwork related noise transfer problems.

In addition to good sound isolation between areas, the background noise must also be of an appropriate level – too quiet, and sounds from one space will be more easily heard; too loud, and people will raise their voices during conversation. When the background noise level is too low, a sound masking system can be installed to create a higher level of inoffensive background noise. This, in fact, was a solution Thorburn Associates employed on a recent counseling center project in which the counseling room common walls were not full height.

Thorburn Associates is currently working on several medical facilities and has a wealth of experience dealing with speech privacy issues. Please feel free to contact us(link to contact page) with any questions you may have.

The HIPAA Standards may be viewed at: http://aspe.hhs.gov/admnsimp/index.shtml.

Confidentiality between a patient and the health provider is one of the basic principles of modern health care. Without confidentiality, the effectiveness of the health care system decreases, due to patient fear of having their medical records revealed and possibly used against them. In 1996, Congress passed the Health Insurance Portability and Accountability Act (HIPAA)… Read more »

Acoustics and LEED / Sustainable Building

As many of you know, the LEED (Leadership in Energy and Environmental Design) Green Building Rating System is a voluntary, consensus-based national standard for developing high-performance, sustainable buildings. It emphasizes state of the art strategies for five broad categories: sustainable site planning; safeguarding water and water efficiency; energy efficiency and renewable energy; conservation of materials and resources; and indoor environmental quality.

The last category, indoor environmental quality, is where Thorburn Associates comes into the picture. As an experienced design and engineering firm with several LEED projects completed, we can help the design team develop acoustic and audiovisual designs and choose products and materials to support sustainable design and LEED certification. Some of our recently completed projects include the following:
certification
Hewlett Foundation Headquarters, Menlo Park, CA Architect: Hawley Peterson & Snyder Architects

Located in Menlo Park, CA, is the new 48,000 sf headquarters for the William and Flora Hewlett Foundation. The success of the sustainable strategies used in the overall project earned it the first LEED v2.0 Gold rating in California and the fifth in the nation.

Thorburn Associates provided both acoustical and audiovisual consulting. Key components include six strategically placed conference rooms, each with videoconference capabilities; two meeting rooms for large presentations and community-wide meetings combinable into one larger room; and a centrally located boardroom. Open office areas, entry courtyard, and the exterior breakout patio all contribute to the open, interactive design, but makes the under floor air distribution system and the wall, floor, and ceiling acoustical treatments that much more important.

SUGEN Building #3, South San Francisco, CA Architect: DES Architects + Engineers

Located in South San Francisco, CA, this Biotech Laboratory Facility includes laboratory and support areas, and all building systems in 67,674 sq. ft. The design team incorporated materials into the interior design that include wall insulation made from recycled natural fibers, particleboard substrates made from straw, and renewable materials such as linoleum flooring.

As part of its LEED Gold certification, the design team incorporated 3 additional elements as new ways of incorporating environmental consciousness into building design: First, this building incorporates a LEEDCI display to promote education about sustainable building practices. Second, although the standard LEED credit does not include lab casework, this building has lab casework made from 100% FSC certified wood. As a third measure the building also has an HVAC system with an estimated energy savings of 46% above code requirements! The energy efficiency helps to reduce the self-generated noise of the system.

Thorburn Associates provided acoustical consulting for sound isolation and mechanical noise/vibration control as well as the design of audiovisual systems for the cafetorium, boardroom, and conference rooms. Key components include portable camera, speech reinforcement for the presenter, videotape playback, video conferencing, and computer graphics displays.

 

As many of you know, the LEED (Leadership in Energy and Environmental Design) Green Building Rating System is a voluntary, consensus-based national standard for developing high-performance, sustainable buildings. It emphasizes state of the art strategies for five broad categories: sustainable site planning; safeguarding water and water efficiency; energy efficiency and renewable energy; conservation of materials… Read more »

ADA and Audiovisual Systems

Every time a sound or speech reinforcement system is designed and installed a hearing assistance system must also be included. ADA Section III-7.5180 Assembly Areas requires:

  • Fixed seating assembly areas that accommodate 50 or more people OR have audio-amplification systems must have a permanently installed assistive learning system.
  • Other assembly areas (not covered in above) must have a permanent system OR an adequate number of electrical outlets or other wiring to support a portable system.
  • A special sign is required which indicates the availability of the system. The minimum number of receivers must be equal to 4% of the total number of seats, but never less than two.
  • The exception is that this does not apply to systems used exclusively for paging, or background music, or a combination of these two uses.

The bottom line, as put by the America Speech-Language-Hearings Association’s response to the ADA was “Ask people about their needs, show respect and sensitivity, use what works (not necessarily what is most expensive), and use your resources creatively and effectively.”

 

Every time a sound or speech reinforcement system is designed and installed a hearing assistance system must also be included. ADA Section III-7.5180 Assembly Areas requires: Fixed seating assembly areas that accommodate 50 or more people OR have audio-amplification systems must have a permanently installed assistive learning system. Other assembly areas (not covered in above)… Read more »

Classroom Acoustics

More than three-quarters of the teachers in a recent poll gave the acoustics in their classrooms a failing grade. The problem is most commonly a “signal to noise” ratio issue, which results in poor speech intelligibility. In general terms – the room is too noisy and it takes a long time for sound to decay within the room. Studies by Maxwell and Evans (1997) have shown that students in schools with high background noise levels tested lower than students in schools with lower background noise levels.

Recently, the American National Standards Institute (ANSI) approved a new set of recommended acoustical specifications for schools (ANSI S12.60-2002). “The criteria, requirements, and guidelines of this Standard are keyed to the acoustical qualities needed to achieve a high degree of speech intelligibility in learning spaces,” according to Paul Schomer, standards director for the Acoustical Society of America (ASA), which publishes the “Classroom Acoustics Design Guide” (2000).

“If followed, this Standard removes acoustical barriers to learning,” he says. “It provides equal access to education for a sizable minority of school children in the United States who may have mild-to-moderate hearing, learning, or attention deficits, suffer frequent ear infections, have limited English language skills, or may otherwise suffer from a substandard acoustical environment. For teachers, working in a classroom that conforms to this Standard can reduce or eliminate voice strain and reduce stress.”

The new ANSI Standard covers:

– Background noise from both inside and outside the building

– Sound transmission of walls, floors, ceilings, and doors

– Impact insulation of floor-ceiling assemblies above core learning spaces

– Reverberation times or the length of time for sound to decay.

BACKGROUND NOISE
The quieter a room is, the lower its background noise level, enhancing speech intelligibility and raising the room’s “signal to noise” ratio. In the case of a teacher in a classroom, “signal” means speech and “noise” is the base noise level in the classroom without the teacher speaking. Noise is measured in Room Criteria (RC) or Noise Criteria (NC) values, which are commonly used to describe the noise from HVAC systems. The primary difference between the NC and RC curves is that the RC curves are more stringent in the low (rumbling) and high (hissy) frequencies.

When documenting the noise level in a room from the mechanical systems, all sources must be considered: How much noise is being transmitted though the wall or roof from the air conditioner unit itself? How much noise travels from the unit down the ductwork to the diffusers? Do the air diffusers create their own noise due to the airflow/air turbulence as air passes thorough the grill? And finally, how is the unit mounted to the structure and is it properly vibration isolated?

Mounting units over or in hallways, and then ducting the air into the classrooms, can resolve many of these acoustical issues. This helps to attenuate the noise from the unit. Silencers or mufflers can be installed in the duct run and acoustical lining can be added to further reduce the noise. If air quality is a concern, one may wish to install AP/Armaflex (manufactured by Armacell), instead of traditional acoustical duct lining.

SOUND ISOLATION
Unlike noise coming from within a building, exterior noise sources are measured by the A and C weighted decibel (dBA/dBC) system. The A-weighted decibel is filtered to respond to the way we hear, while Cweighting is closer to a true flat response. According to the Standard, the building shell should control outside noise sources to levels of 35 dBA. If the exterior C-weighted sound level is more than 45 decibels above the A-weighted sound levels, the Standard requires additional acoustical mitigations, for example at schools near airports, major rail lines, or roads with a high volume of truck traffic.

Sound Isolation or Noise Reduction between classrooms is an issue that must also be addressed. In general we have found that walls should have a minimum Sound Transmission Class (STC) of 50 as has been supported by the ANSI Classroom Acoustics Standard. When addressing sound isolation between rooms it is very important to look at all of the pathways for sound to enter the room: doors, windows, penetrations of the walls by ducts, pipes and conduits, and holes made in walls by recessed electrical panels and fire extinguisher cabinets. These can all significantly reduce the Noise Reduction properties of the partition.

REVERBERATION TIME
Another section of the Standard for Acoustical Design of Classrooms covers the build-up of noise in the room itself. This is typically measured in Reverberation Time (RT60), or the length of time it takes for sound to decay 60 decibels or to one millionth of its initial level. Reverberation can be reduced by installing sound absorbing panels or an acoustical tile ceiling system. A major design challenge in
classrooms concerns the need for wall-mounted writing surfaces to be abuse resistant while also non-reflective of sound.

The suggested Reverberation Times for classrooms are based on classroom size:
Less than 10,000 cu. ft. – 0.6 seconds

10,000 to 20,000 cu. ft. – 0.7 seconds

More than 20,000 cu. ft. – consult an expert

In addition to these specifications, the Reverberation Time for distance learning rooms should be less than 0.5 seconds, with no discrete echoes.

As school districts begin to adopt this standard, architects and engineers will need to address these issues just as they do for egress and heating and cooling building codes. While primarily directed at K-12 schools in the United States, the new Standard also could be applied internationally and at the college level. ANSI S12.60-2002 (Acoustical Performance Criteria, Design Requirements, and Guidelines for Schools Standard) is 50 pages long. The entire document can be downloaded for $35 from the ANSI web store http://webstore.ansi.org.

This is an abridged version of the “Classroom Acoustics ANSI Standard” article that Steve Thorburn Authored for Archi-Tech magazine in their July/August 2003 issue.

More than three-quarters of the teachers in a recent poll gave the acoustics in their classrooms a failing grade. The problem is most commonly a “signal to noise” ratio issue, which results in poor speech intelligibility. In general terms – the room is too noisy and it takes a long time for sound to decay… Read more »

New Advances in Video Conferencing Technology H.264

A new video conferencing standard, H.264, delivers twice the video quality currently experienced in video conferencing meetings. H.264 provides a far more efficient mechanism for compressing and decompressing motion video. This mechanism or algorithm requires significantly less bandwidth to transmit a motion image than has previously been possible. For videoconferencing, H.264 requires only 50% of the previously required bandwidth to provide the same quality of image. This means that if current bandwidth is maintained, substantially higher video quality will be achieved or we can cut our telecommunications costs in half or by two thirds and maintain our current level of quality!

If you are using IP (internet protocol) based video conferencing in a large campus environment then H.264 will reduce the total network traffic, freeing up bandwidth for either additional meetings or other uses.

So what does all of this mean to us … if you or your client is going to invest in video conferencing equipment make sure that the system is H.264 compliant. While conferencing systems that support H.264 will communicate to older systems you will not see the benefit of the faster algorithm until both “ends” of the conference use H.264 compatible units.

A new video conferencing standard, H.264, delivers twice the video quality currently experienced in video conferencing meetings. H.264 provides a far more efficient mechanism for compressing and decompressing motion video. This mechanism or algorithm requires significantly less bandwidth to transmit a motion image than has previously been possible. For videoconferencing, H.264 requires only 50% of… Read more »