Tuesday, November 12, 2019

Understanding STC & FSTC Ratings

Here at SoundAway, we're in the business of sound. More precisely, we deal with sound isolation and changing sound quality in specific spaces to best suit your needs. That space may be a large auditorium or concert hall where sounds need to be contoured to reach each individual section of the space, or a small piano practice room where sounds need to be attenuated to a volume low enough so as not to disturb individuals practicing in adjacent areas.

Sound Vibrations
Sound vibrations decrease in volume as they travel through the air, as is demonstrated by yelling to someone standing a block away from you and someone else 10 feet away. The closer to the sound source, the louder it seems.

In addition to volume reduction caused by increased distance, you can also affect sound loudness by introducing a physical barrier to block the sound. This barrier could be a wall, a door, a window or some type of panel. Each of these barriers will have a different effect on the sound it’s blocking, depending on the sound-blocking ability.

Human sensitivity to changes in sound intensity levels is also worth considering. Measurement of sensitivity to differences in the rate of change of auditory signal parameters is complex and must take into account duration, extent of change, and velocity of the changing sound. Here is what you can typically expect:
1 dB / generally not perceptible
3 dB / just perceptible
5 dB / clearly noticeable
10 dB / twice as loud (or half as loud if it describes drop in sound level)
20 dB four times as loud

There are Two Measurement Units of Airborne Noise:
  1. Sound Transmission Class (STC) – associated with tests carried out within a controlled laboratory environment. Laboratory tests results are generally higher than those performed in the field.
  2. Field Transmission class (FSTC) – associated with tests carried out in the field. This allows for more of a real-life measurement that factors in things such as background noise levels, surface areas, environmental factors, etc.
Requirements of the National Building Code allow for a minimum acoustic rating of FSTC 50. At this level, the soundproofing is acceptable but you may still be able to hear a neighbor who snores loudly. FSTC 55 is a bit more comfortable and the desired acoustic comfort is around FSTC 60.

Classification / STC / FSTC
Minimum code / 50 / 45
Minimum quality / 55 / 50
Medium quality / 60 / 55
High quality / 65 / 60

STC Ratings
In the soundproofing industry, the ability of a barrier such as a wall or a door to reduce sound volume from one side of the barrier to the other is measured by a standard called STC, which stands for sound transmission class. This is a standard used primarily in the U.S. to rate partitions in a building as to their sound-attenuating capability. These partitions include interior and exterior walls, doors, windows, floors and ceilings. STC ratings provide you with an approximate idea of how much airborne sound a particular barrier such as an interior wall could stop. Simply stated, sound volume ratings in decibels (dB), measuring how loud a sound is, are recorded on both sides of the barrier being tested.

If the noise you're measuring is 90 dB, which is the volume of a typical police car siren, and the barrier decreases the sound to 70 dB on the other side of the barrier, you're said to have a 20 dB transmission loss. Note that if the test tone used in the above example is altered in pitch (frequency or Hz), the resulting transmission loss figure may be totally different.

STC ratings, introduced in 1961 as a means for comparing various types of barriers (wall, window, door, floor and ceiling assemblies), are often used to compare different products from competing manufacturers. STC is determined by taking transmission loss figures at 16 standard frequencies falling between 125 Hz and 4000 Hz. The results are plotted on a graph to form a curve, and this curve is compared with standard STC curves the industry has adopted.

STC Examples - Expected Field Results
45 / Normal voice not audible, raised voice plainly audible
50 / Loud voice understandable, raised voice not audible
55 / Shouting voice understandable, loud voice plainly audible
60 / Shouting playing audible, loud voice audible
65 / Shouting audible, loud voice not audible
70 / Very loud music understandable
75 / Very loud music plainly audible
80 / Very loud music audible

Note: The International Building Code requires a minimum of STC 50 for floors, ceilings and walls in new construction.

Shortcomings of STC Ratings
Typically, STC ratings numbers run between 27 and 72. The higher the number, the better the soundproofing capability of the barrier tested. It is important to note that STC Ratings are measured on a logarithmic scale: the values are not linear. Therefore, sound measuring at 50 decibels is not twice as loud as a 25-decibel sound. Here are some useful examples:

STC 27 – Single-pane window glass
STC 46 – 1/2” drywall glued to a 6” concrete block and painted on both sides
STC 72 – 8” painted concrete block wall with 1/2” drywall on both sides, installed on independent steel studs, with insulation in all cavities

One of the problems that exists with accurate STC ratings is that frequencies below 125 dB are not considered. Unfortunately, many sound-isolation problems come from noise sources that are below this 125 dB threshold. This includes most sounds emanating from home theaters; noise from heavy equipment, airplanes and trucks; musical instruments such as guitars, bass guitars and drums; and certain industrial equipment. For this reason, it's a mistake to rely solely on STC ratings to determine sound isolation capabilities, especially where low-frequency sounds are involved.

Monday, November 11, 2019

Understanding IIC Ratings

Impact insulation class (IIC) ratings represent a standard used in the building trade to designate the capability of a floor/ceiling assembly in a multistory building to attenuate sounds transmitting from one level to the next level below. Whenever something that produces sound occurs on an upper floor, whether that be a footfall hitting the floor, an object dropping or furniture being moved about, the amount of noise that's transmitted to the room below, called impact sound transmission, can be measured on a sound scale developed for this purpose.

The IIC was developed by ATSM International (formerly the American Society for Testing and Materials) using ATSM Method E989, incorporating a five-hammer tapping machine that's specified in ATSM Method E492. The five hammers on the tapping machine are placed in a line, and during testing, each hammer is lifted and then dropped in sequence, causing a total of 20 impacts per second hitting the floor. A sound level meter is placed in the room below to measure the difference between the initial sound, the frequency and force of which is known, and the resulting sound below. An industry standard is used to determine the sound reduction, or transmission loss, in dB (decibels).

Impact Sound Transmission
Unwanted sound vibrations transmitted through floor/ceiling assemblies are annoying, and assemblies that can reduce or eliminate these noise levels are highly desirable. These impact sound transmissions are attenuated, or lessened, by a variety of different flooring materials and floor coverings. Consider the difference in noise transmission to the room below if you have a bare hardwood floor or a floor covered in a thick carpet on top of a quality pad. The difference is significant.

Each of these floors and floor covering types have an IIC rating, typically falling somewhere between 25 and 85+. Higher numbers signify better noise reduction. IIC 50 would be considered the least amount of acceptable impact sound transmission between occupied floors and would be unsatisfactory to many occupying the lower floor. IIC 60 is considered medium noise reduction, and IIC 65 would likely be an acceptable noise reduction level for most lower-level occupants.

Determining IIC
In testing a sample floor/ceiling assembly in the laboratory using a five-hammer tapping machine, sounds are generated at 16 standard frequencies between 100 Hz and 3150 Hz. Results from each tap get plotted on a graph, each point depending on the amount of lost impact sound from each tap. The resulting graph is then compared to a standard reference graph to determine the IIC rating.
This testing, done in a laboratory on a single sample section of a floor/ceiling assembly, is the least accurate of two methods for determining a specific IIC rating. A more accurate and realistic rating is obtained through a testing method occurring in an actual building after installation of the floors. When testing is conducted under these real-world conditions, a total IIC value is obtained:
  • Floor covering
  • Subfloor
  • Underlayment
  • Floor joists
  • Lower room ceiling
  • Sealants and adhesives used for installation
  • Sound-deadening materials such as insulation and resilient channels

This method of testing is known as the field impact insulation class (FIIC).

Cushioning the Blow
Quite simply, one of the easiest and most effective ways of reducing impact sound transmission is by “cushioning the blow.” Adding a thick carpet with a high-quality carpet pad is extremely effective in lessening impact sound transmission and improving a floor's IIC rating.

Floors made from resilient materials such as rubber, cork or vinyl can also provide a slight improvement in sound reduction. Floating floors, such as a wood finished floor sitting on a resilient underlayment can also provide a higher IIC rating value. On the other hand, a concrete floor covered directly with a non-resilient material such as wood, tile or stone has a low IIC due to the fact that there is no “give” in this type of flooring system.

Additionally, since the current IIC rating system only tests sounds within a range of 125 Hz to 3150 Hz, which is approximately the sound range of the human voice, noises existing below 125 Hz, such as those that may be heard when someone is walking above on a floor with a lightweight joist system, may be audible. Noises made by people walking on a floor with a loose joist construction are also not accurately accounted for by standard IIC testing.

Thursday, October 17, 2019

How to Install Whisperwave Clouds & Baffles

The Whisperwave line includes some of the best sound absorbing hanging baffles and clouds on the market. Featuring an s-shaped design that is visually appealing and with options available in colors from earth-toned to bright and vibrant, these products are an obvious choice. Install in industrial facilities, auditoriums, high-ceiling office, classrooms, or any space that is in need of noise control. For those in need of a bit of guidance, we have outlined a step-by-step guide to walk you through it.

Make Sure You Have the Proper Hanging Materials.
Our Whisperwave Clouds and Baffles come with the needed stainless-steel corkscrews for wire suspension (smaller clouds, four per 2’ x 4’, and larger clouds, six per 48” x 96”) but they will arrive separately. Ensure you have these corkscrews on hand or purchase them before installing the product.
For Vertical Suspended Baffles, place the suspension points where necessary on your Whisperwave Baffle. Insert (two per baffle) the corkscrew by pressing down firmly and turning clockwise until the top of the coil is completely seated alongside the top of the baffle. Then suspend the baffle using hanging wires and anchors. Voila, you’re done!

Horizontal Suspended Whsiperwave Clouds take a little bit more effort to install. Our anchor placement guide comes in handy:
The placement of the corkscrews on your horizontal panel depends on the size of your cloud.

To find the approximate distance away from the sides to install the corkscrew hangers, multiply the width and length by 0.20, similar to how you would find the diagonal length of a square.

For example, for 4’ x 8’ Whisperwave Clouds, to set the corkscrew hangers, you’ll want to have 3 corkscrews along the horizontal side of the baffle, 1 in the middle approximately 8 inches from the edge and approximately 11.3” from the corners.

For 2’ x 4’ Whisperwave Clouds, set the corkscrew hangers 4.75” away from the sides and 9.5” in the front and back of the cloud. Be sure to keep all hanging wires plumb to ensure the best results for your baffling.

Thursday, May 23, 2019

Acoustic Paneling Options for Restaurants

If you own a restaurant, your key goals are to provide customers with great food and a great dining experience. This goes beyond delicious ingredients, great customer service and a clean dining area; the sound and ambience of your restaurant can play a big role in a patron’s decision to frequent your business. Think back to the times you ate at a restaurant that was so noisy you had to shout to talk with your friends. Did you want to go back there and eat again? Luckily, there are several ways to control the noise in your restaurant to provide a top-quality experience for your customers.

Wall/Ceiling Paneling
Fabric-wrapped acoustic panels, such as those we carry from Ambience, are a great choice for sound absorption that stays in line with your dining room’s color scheme and design. Every panel is wrapped in high-quality textured fabric and can be paired with any number of Guilford of Maine acoustic fabrics, and FR701 is one of our most popular options. Standard sizes of 2’ x 2’ or 2’ x 4’ are common for most restaurateurs' needs, but we can customize these panels up to 5’ x 10’ in size.

If your walls aren’t a viable option for acoustic paneling, ceiling-mounted panels are a great alternative. Clean, simple and fire-resistant, ceiling panels can blend right in for an out of sight, out of mind design that reduces reverberation and overall noise levels. Most customers won’t even notice them!

Ceiling Clouds
A cloud-style ceiling panel incorporates design to a dining space while adding plenty of function. Arrange them in your own patterns around chandeliers and ceiling fans, or line them up and space them evenly over large open areas with communal dining seating. Panels can be mounted easily to a ceiling with hooks and cables and provide a unique visual component to an otherwise unused, undecorated space.

Baffles or Waves
We’ve written previous posts about utilizing Rondo baffles or Whisperwave products when you’re interested in a unique, eye-catching panel design for your space, and the same holds true for restaurants. They’re a great choice for layered sound reduction and can be mounted at various heights for a stylish, asymmetric look depending on your space.

Outfitting your restaurant with sound reduction panels is as much functional as it is about design. To make sure you’re choosing paneling that’s right for your space, contact the SoundAway team and discuss your options with an acoustical analysis. We’re happy to quote you on a variety of projects that scale to your needs!

Thursday, April 25, 2019

When Rondo Sound Baffles Are the Perfect Choice

When space is limited and you need sound-absorbing technology that isn’t visually distracting but has some architectural style, SONEXⓇ Rondo sound baffles are an excellent solution. Available in a variety of colors and configurable vertically or horizontally, Rondo sound baffles are great for large interior areas due to their ability to prevent noise buildup.

SoundAway’s client base regularly utilizes Rondo baffles for spaces such as indoor pools, music rooms, open floor plan offices, reception areas and much more. These baffles are specifically designed to lower reverberation while allowing crisp sound to naturally carry over large spaces as intended. Arrange them vertically from the ceiling of a multipurpose conference room, hand them from light fixtures, or fix them in a unique, artistic pattern to add to the room’s design. They can also be installed horizontally like a string of beads that hug the ceiling, staying out of sight and blending into the room’s architecture.

Rondo sound baffles are made of premium Class 1 fire-rated Willtec melamine foam, which has a low-density, open-cell structure to comply with fire-resistance and heat-shielding standards without adding too much weight to your rafters or ceiling frame. They pass UL 181 Section 11 standards for microbial growth and have a fungal resistance rating of #0 per ASTM G21, which is what makes these baffles an excellent choice for indoor pools or gyms. Each baffle is 6” in diameter by 24” in length and comes with corkscrew hangers for easy installation.

When your space calls for efficient and stylish sound-reduction panels that don’t provide a visual distraction or take up much physical space, consider Rondo sound baffles from SoundAway.com. We’re happy to answer any questions you may have to help you choose the best baffles for your sound-absorption project!

Wednesday, March 27, 2019

Whisperwave Your Project From Top to Bottom

When it comes to controlling the acoustics in a common workspace, it's important to consider style as much as function. A standard rectangular acoustical panel might not fit with a modern office space design, and sizing options could be limited. Or maybe the space in question is a modern music venue. These spaces want to be as comfortably stylish as they are functional. In either of these instances, Whisperwave™ panels are a fantastic option.

Imagine you manage facilities at a hip, modern office with exposed rafters and you have large, open meeting spaces where sound can carry. Putting up walls can ruin the office atmosphere your company wants to create, but you have to do something to reduce noise while keeping the aesthetics of your space. Ceiling clouds are a perfect solution! Hung parallel to the floor or ceiling, these curved acoustical panels are made from Class A fire-rated melamine foam and are incredibly lightweight. Their curved style gives them a modern look, and they can be mounted at various heights for an asymmetric vibe or incorporated into an existing design. If you have limited ceiling space to work with but need more noise and reverberation reduction, ceiling baffles are ideal. Hung perpendicular to the floor, these baffles can be staggered at various heights to create a layered wall of soundproofing between spaces with 12” ribbon baffles and 24” standard baffles available. Baffles are ideal for high ceilings or spaces where one needs to limit blocking of light or fire sprinklers.

After you’ve tackled sound carrying up toward the ceiling, it’s important to address your space’s walls. Whisperwave™ offers a line of ribbon-styled wall panels that can be mounted directly to the wall for a stylish and practical way to address noise. Use them in recording studios or create a feature wall out of the panels for a unique design aesthetic. They are lightweight, easy to install and look great in a modern setting.

We offer this fantastic line in natural white, natural gray and standard or premium HPC colors, and we’re excited to discuss how these great products can be incorporated into your reverb reduction project. Contact us with questions or concerns, or get a quick quote so you can upgrade your room’s design and cut down on noise at the same time. We think you’ll love the modern look, easy maintenance and practicality that Whisperwave™ can offer!

Wednesday, February 27, 2019

Soundproofing Your Studio Doors & Windows

Whether it’s a recording studio that needs complete soundproofing or a home theater or study where ideal acoustics are preferred, controlling the noise coming into a room is as important as controlling the noise you produce. Plenty of attention is given to a studio’s walls, but it’s also important to pay attention to windows and doors. Why place so much emphasis on a studio’s doors and windows?

It’s a common misconception that air and sound travel the same way. While a small gap or crack around a window might leak out just a small amount of air, the amount of sound emitted is exponentially higher. In fact, a small gap in your door or window can reduce your soundproofing effectiveness by upwards of 50 percent! There are plenty of DIY remedies to consider, but installing professionally engineered doors and windows goes a long way to reaching your soundproofing needs.

QuietSpec studio doors are an ideal single-leaf option for STC- and OTIC-rated acoustic doors. They’re engineered with a customized, high-mass, viscoelastic damping core and finished off in a clean birch that can be stained or painted as desired. Different heights and widths are available, as are core thicknesses depending on your needs. Acoustic-rated thresholds are included as well, giving you complete soundproofing from top to bottom. We ship these state-of-the-art soundproof doors in just four weeks after receipt of order, which is an average of three times faster than our competitors!

What about windows picking up ambient noise from the outdoors or other areas of a building? Quiescent soundproof windows are an STC-rated custom solution designed to fit and function with any wall thickness. Made with an anodized aluminum frame, these acoustical windows are suitable for interior or exterior use with angled or vertical options and laminated panes for 45 - 56 STC configurations. While every soundproofing space is unique, our team of experts can customize and ship these soundproof studio windows in as little as 5-6 weeks after receipt of order!


When it comes to soundproofing a studio, home theater or quiet space, just as much attention should be given to doors and windows as is given to walls, floors and ceilings. With proper consideration and customization, you can make sure your doors and windows are keeping sound from penetrating or escaping and working properly for your space. If you have any questions or concerns about which door and window soundproofing options are best for your space, contact us at 866-768-6381 to speak with our soundproofing professionals. You can also leave us comments on this post and we’ll be happy to assist!