Office acoustics and green building trends - can they play nice together? CCR ASSOCIATES' own Charles Roy was recently quoted by an article in Buildings magazine regarding this topic:
Both the design of an office space and its materials should be carefully considered to address the ABCs (absorb, block, and cover) of acoustics; this has proven effective for ensuring speech privacy for years. According to Charles C. Roy, president, CCR Associates LLC, an Essex, CT-based acoustical consulting firm, "… the absorption (ceilings, furniture, and carpet), blocking (walls, furniture, and ceilings) and covering of sound (controlling the ambient background with soundmasking) are critical components in addressing office acoustics. In general, when one segment or another is ignored, the cumulative outcome for speech privacy will be less than when all are addressed equally."...
LEED and other green building techniques can, without foresight, have a detrimental effect on office acoustics. However, so can many other building practices, green or not. With proper design and attentiveness to the ABCs, green offices can indeed "play nice" with acoustics.
November 17, 2009
July 28, 2009
Setting the Stage for Speech Privacy
It pays to keep a common sense approach to office acoustics. There are numerous practical and economical ways to cut down on unwanted noise transmission that are not only highly effective, but necessary first steps towards building a desirable acoustic environment. Remediation strategies such as electronic sound masking can only be effective if the underlying structural environment is relatively sound.
As acoustical consultants, CCR ASSOCIATES is frequently called in to assess ongoing acoustical problems in currently occupied office space. Once on site, it often becomes apparent that many acoustical problems are due to structural/design problems in the office, and that these design problems must be resolved before one can accurately assess the potential effectiveness of sound masking. Wall and ceiling voids, open air grills, low/no cubicle walls, poorly sealing doors and windows, poorly designed workstations, etc. are all very common. Common sense dictates that sound will transmit through openings, and that these openings should be sealed, if possible.
The chart above demonstrates how important it is to fix any underlying structural acoustical problems before attempting further remediation. Until an office reaches a Privacy Index of 60 or above, little acoustical benefit can be gained from sound masking or other electronic acoustical remediation. Above 60, increases in PI through sound masking or other means are considerably more effective.
As acoustical consultants, CCR ASSOCIATES is frequently called in to assess ongoing acoustical problems in currently occupied office space. Once on site, it often becomes apparent that many acoustical problems are due to structural/design problems in the office, and that these design problems must be resolved before one can accurately assess the potential effectiveness of sound masking. Wall and ceiling voids, open air grills, low/no cubicle walls, poorly sealing doors and windows, poorly designed workstations, etc. are all very common. Common sense dictates that sound will transmit through openings, and that these openings should be sealed, if possible.
The chart above demonstrates how important it is to fix any underlying structural acoustical problems before attempting further remediation. Until an office reaches a Privacy Index of 60 or above, little acoustical benefit can be gained from sound masking or other electronic acoustical remediation. Above 60, increases in PI through sound masking or other means are considerably more effective.
June 18, 2009
Noise Cancellation vs. Sound Masking
Though the terms are often used interchangeably, noise cancellation and sound masking utilize different technologies and are used for different purposes.
Technically speaking, it is nearly impossible to truly "cancel" noise in a typical human environment, due to the highly variable and dynamic nature of most living and working space. However, you can come close if you are able to isolate and control the noise from the greater environment. Headphones are frequently used for this purpose. Settings in which the ambient sound frequencies are relatively static and easily predicted, such as on an airplane, or close to a particular machine, are appropriate for noise cancellation technology. Noise canceling headphones or speakers assess the current ambient sounds, and generate a tone with the inverse wavelength, which in effect cancels out all sounds of the targeted wavelength.
Homes, offices, stores, and most other human environments display a highly dynamic range of sound frequencies, making it very difficult and costly to monitor and cancel frequencies in the manner of typical noise cancellation technology. Also, it is beyond the scope of most if not all existing noise cancellation technologies to differentiate between undesirable background noise (chatter), and useful human vocalization (desirable communication). It would clearly be unhelpful to cancel or otherwise scatter all human speech in a home or office.
Sound masking masks (as the name implies) rather than cancels sounds. You have probably experienced the effects of sound masking in your home when you stand at the kitchen sink with the water running, and try to talk with someone across the room. The sound of the running water makes it difficult to clearly understand the person talking. Once you turn the tap off, you can once again hear the conversation clearly. Running water masks human speech very well, without distracting or annoying the listener, because it creates a random, yet relatively uniform sound, within a specific frequency spectrum.
To be effective, sound masking systems must generate sound that is both random and within a specific range of frequency and decibels. Typical humans will actively listen to sounds that form a recognizable pattern, like music or speech, but will tune out sounds that they can't make sense of, like static (unless the sound becomes too loud). In an office, sound masking works by injecting a random, low-level background noise that correlates in frequency to typical human speech, making it difficult to understand conversations outside of the listener's immediate area. Care must be taken to insure that both the decibel level and frequency of the sound masking system is appropriate for the environment. If the sound masking is set too loud, or at the wrong frequency, occupants may have a negative response.
To set the sound masking to the appropriate levels, the office must first be assessed for it's existing acoustical qualities, which include the size of the office, the physical materials of the office (walls, ceilings, doors, partitions, etc.), the furniture in the office, the number of occupants and their normal functions (customer service, engineers, managers, etc.), typical background noise levels in the office (HVAC, copiers, computers, etc.), and purpose of the office space (quiet work area, team work area, call center, meeting room, etc.). Depending on the circumstances, the system can be tuned for greater speech privacy (for example, a work area that requires mental concentration with little distraction) or lesser speech privacy (for example, a collaborative work area, where employees hold informal meetings as well as work independently).
Technically speaking, it is nearly impossible to truly "cancel" noise in a typical human environment, due to the highly variable and dynamic nature of most living and working space. However, you can come close if you are able to isolate and control the noise from the greater environment. Headphones are frequently used for this purpose. Settings in which the ambient sound frequencies are relatively static and easily predicted, such as on an airplane, or close to a particular machine, are appropriate for noise cancellation technology. Noise canceling headphones or speakers assess the current ambient sounds, and generate a tone with the inverse wavelength, which in effect cancels out all sounds of the targeted wavelength.
Homes, offices, stores, and most other human environments display a highly dynamic range of sound frequencies, making it very difficult and costly to monitor and cancel frequencies in the manner of typical noise cancellation technology. Also, it is beyond the scope of most if not all existing noise cancellation technologies to differentiate between undesirable background noise (chatter), and useful human vocalization (desirable communication). It would clearly be unhelpful to cancel or otherwise scatter all human speech in a home or office.Sound masking masks (as the name implies) rather than cancels sounds. You have probably experienced the effects of sound masking in your home when you stand at the kitchen sink with the water running, and try to talk with someone across the room. The sound of the running water makes it difficult to clearly understand the person talking. Once you turn the tap off, you can once again hear the conversation clearly. Running water masks human speech very well, without distracting or annoying the listener, because it creates a random, yet relatively uniform sound, within a specific frequency spectrum.
To be effective, sound masking systems must generate sound that is both random and within a specific range of frequency and decibels. Typical humans will actively listen to sounds that form a recognizable pattern, like music or speech, but will tune out sounds that they can't make sense of, like static (unless the sound becomes too loud). In an office, sound masking works by injecting a random, low-level background noise that correlates in frequency to typical human speech, making it difficult to understand conversations outside of the listener's immediate area. Care must be taken to insure that both the decibel level and frequency of the sound masking system is appropriate for the environment. If the sound masking is set too loud, or at the wrong frequency, occupants may have a negative response.
To set the sound masking to the appropriate levels, the office must first be assessed for it's existing acoustical qualities, which include the size of the office, the physical materials of the office (walls, ceilings, doors, partitions, etc.), the furniture in the office, the number of occupants and their normal functions (customer service, engineers, managers, etc.), typical background noise levels in the office (HVAC, copiers, computers, etc.), and purpose of the office space (quiet work area, team work area, call center, meeting room, etc.). Depending on the circumstances, the system can be tuned for greater speech privacy (for example, a work area that requires mental concentration with little distraction) or lesser speech privacy (for example, a collaborative work area, where employees hold informal meetings as well as work independently).
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