Sound Issues fall into a few basic categories. By correctly defining and categorizing your sound problem or concern, you can effectively design a treatment for the space without spending money on unnecessary mitigation approaches that do not yield results.
Contact Us About Your Sound Issues
Checklist to Determine Noise Issue and Treatment Options:
- What is the main problem or concern?
- Echo & Reverberation : Is it too noisy to clearly understand someone? This is common in larger rooms, hard-surface walls and floor types (such as tile and glass).
- Sound Absorption should be used to reduce reverberation.
- Transmission: Is the concern coming from a room/area other than the one you are in? This could include neighbors walking around upstairs, or listening to the TV too loud next door.
- Soundproofing Methods should be used to increase STC or IIC
- Vibration Isolation may be needed to reduce structure-borne transmission
- Speech Privacy/Distraction within an Open Space: Is it “too quiet” at times in your space, making everything else easier to hear?
- Sound Masking should be considered to add ambient background noise to improve speech privacy.
- Other: Are you designing or building a unique structure, or dealing with exterior or industrial noise issues?
- Consider bringing on acoustic consultant to provide custom solution and best design practices, or perform field testing to better define the problem.
- Echo & Reverberation : Is it too noisy to clearly understand someone? This is common in larger rooms, hard-surface walls and floor types (such as tile and glass).
- How to Treat the Issue? Source-Path-Receiver: Every acoustic problem may be broken down into 3 segments. This is the source, from which the sound or vibration emanates, the path along which it travels, and the receiver that is affected by the noise source.
- Source: This may be human speech, music & television, or vibrating equipment, among other sources.
- Path: wall, floor, or exterior path where the sound propagates (or travels)
- Receiver: Adjacencies and sensitivities, such as sleeping tenants and next-door neighbors, focused office workers, or a spa sharing the demising wall
- What is the Construction Stage? A number of options are available in Schematic and Detailed Design that are no longer feasible after Occupancy or during Retrofits.
Operational vs. Architectural Solutions
Many solutions will include a blend of Operational and Architectural approaches. With the growing inventory of multi-use developments as well as crossfit gyms and other noise-generating tenants in shopping centers (next to spas, restaurants, and offices), there is a reasonable expectation of a blended approach for acoustic mitigation.
While an STC of 45 may be appropriate for adjacent office spaces, a new Fitness or Music tenant may move in causing significant strain. Therefore, designing and building STC 55+ may be appropriate for many demising walls with uncertain future tenant occupancy. However, this may still be insufficient for extremely loud noise levels. In those cases, maximum noise levels should be written into the lease agreement to ensure that noise complaints are minimized.
Designing and building all demising walls to an STC 65+ would likely be untenable and not cost-effective. Therefore, by increasing the target STC to 55 and by adding noise restrictions into tenant contracts, property managers and developers can use a blended approach which that reduce noise issues without a significant cost.
| Rather than building an STC 65 wall for each partition, sometimes it’s just easier to turn down the speakers. |
*Side Note: enforcing Maximum Noise Levels can be difficult, since the equipment needed to accurately measure and time-average noise is expensive. However, a consultant may be brought out to site one time after commissioning of the speaker systems to set max sound levels. The sound control panel should then be photographed and control panel settings labeled or marked. The control panel should then be locked in a closet or cabinet to prevent adjustments. If noise complaints begin, the panel may be inspected to ensure no changes have occurred.
Overview of Treatment Methods
Soundproofing
Soundproofing means reducing and preventing unwanted noise from traveling between point A and point B. When reducing airborne noise it is measured in STC (Sound Transmission Class), and when reducing footfall or other structure-borne noises it is measured in IIC (Impact Insulation Class).
| Walls have an STC Rating only, while floors have STC and IIC Ratings. |
Methods and systems that are effective at soundproofing airborne noises are not necessarily effective at reducing structural vibrations. For instance, carpeting on heavy pads is extremely effective at reducing footfall noise from being heard below, but will make minimal, if any, difference at reducing the sound of a TV or stereo. On the other hand, concrete decks often have very high STC performance, but because they transmit vibration so well, are often not sufficient for footfall reduction without a resiliently-mounted ceiling or sound mat.
Soundproofing is NOT the ability to reduce noise within a space or lower reverberation. Often-times we see clients installing Homasote or other sound mats on their walls and ceilings to reduce echo – while these products are effective at damping structural vibrations, they are even less effective than standard drywall at absorbing airborne noise.
Products designed for soundproofing are generally dense, hard materials that reflect sound. Many of them also have an element of elasticity, designed to dampen vibration. Another subset of soundproofing materials are designed to create air gaps and provide similar resilient offsets from stiff, rigid materials that prevents structure-borne transmission of sound.
| A common mistake we find is that restaurant owners and other end users will try to use absorption panels to reduce the amount of sound this is being transmitted to adjacent spaces. In this case, the sound must be Blocked, rather than Absorbed, since there will be minimal improvement by adding acoustic panels into the space. |
Sound Absorption
Sound Absorption increases the sound quality in a space by:
- Primarily, reducing echo and reverberation, and
- Secondarily, with some limitations, reducing the dBA level within the space.
Absorption may be a critical consideration for restaurants, churches, and auditoriums where speech intelligibility and crispness are important features.
Absorption does NOT reduce sound transmission from space-to-space. We often see nightclub or bar owners invest in panels to reduce the sound heard by neighbors upstairs or across the street, with no benefit.
Products designed for absorption are generally soft and porous, allowing sound waves and air particles to become “trapped” within the material.
Sound Masking
Sound masking involves adding constant, relatively low-volume background noise into a space in order to reduce sound distractions and improve speech privacy.
Sound masking differs from acoustic treatment or soundproofing products, since it is designed to add noise into a space, rather than diminish it.
| Open offices are often best treated with sound masking. Adding acoustic panels into a bullpen area does not reduce noise between cubicles. Likewise, simply laying fiberglass batt on top of ceiling grids does not prevent flanking around a wall – sound masking is much more effective at covering the adjacent conversations. |
When balanced, tuned, and commissioned properly, staff and visitors should not actively notice the sound masking system. However, the number of distractions per hour drops dramatically, and speech privacy is greatly enhanced so that nearby personnel cannot hear private conversations.
Improperly balanced systems may be too low to appropriately mask faraway conversations or distractions, or if improperly tuned the system may be too “hissy” and annoy personnel. Sound masking systems should be installed, balanced, and tuned by experienced acoustical personnel, not solely by low voltage contractors with expertise in communications systems.
