Sheriff’s Office – Sound Masking

The Pinellas County’s Sheriff’s Office was struggling with a number of noise complaints. Among other things, they were concerned with the sound privacy in interview rooms, to ensure that interviews were conducted in a confidential manner.

So they contacted Commercial Acoustics. After an initial site visit, we prepared a solution that would provide significant speech privacy without the need for a major construction budget. By pairing sound masking speaker systems with additional soundproofing wall membranes, we were able to increase the STC of the walls while also masking background noise.

The combination of the two approaches yielded impressive results: primarily, that officers no longer needed to worry about being overheard while they worked (and were not distracted by other conversations). While the sound masking system was installed, tuned, and implemented in a single day, the soundproofing membrane for the walls required an additional several weeks to complete each of the 10 interview rooms. This is a level of soundproofing that many law enforcement agencies do not require, but which provides superior soundproofing for a wide array of applications.

For many clients, the benefit of sound-masking cannot be over-stressed. The highly-tuned speakers provide an exceptional ability to mask background noise, and thereby reduce the “dynamic range” that so many office employees find extremely distracting. The speakers are hidden from view, concealed behind the ACT. They do not interfere with voice recordings, and actually enhance the speech privacy over phone conversations. Affordably priced, at approximately $1.00-$2.50/square foot, it can make the difference between a noisy workspace and an acoustically-treated office.

Lake House Acoustical Treatment

At the Lake House room in a luxury, master-planned community in Lake Nona, Florida, an unexpected issue arose.

The aesthetics of the room were impeccable. The room was adorned floor to ceiling windows along the walls, and custom chandeliers in the center. The hardwood floor was especially unique – charred in an oven for hours, then sand blasted to remove the marks – it felt more like tile than traditional hardwood. All of the mechanical devices were run by a single, wall-mounted flat-screen device, including the projector, room divider, and air conditioning.

However, regardless of the premium finishes and expensive electronics, one problem remained identified. With all of these hard surfaces, the reverberation time in the space was surprisingly long. While local residents use the room for meetings or yoga classes, it became very difficult to communicate with the echo that they experienced. A phenomenon known as “speech intelligibility”, this is a common issue experienced in gyms, auditoriums, and restaurants.

Unwanted reverberation or echo occurs when areas have large volumes and smooth, hard surfaces that reflect the sound back inward. When this happens, humans hear reflected noises as new words are being spoken, and have a difficult time identifying exactly what is being said.

The solution is to add soft, acoustical materials into the space, allowing the sound to be absorbed into its porous mass. The sound is then transformed into thermal energy and dissipated into the environment. The amount of absorption needed in a space is determined by the specific geometry and materials contained within.

For the Lake House, our production team custom-fabricated 100 2’ Wide x 4’ Long x 2” Thick Acoustical Panels, fabric-covered in the desired texture and color. Within 2 weeks the panels were delivered to site, and installed into the corrugated metal deck of the large room. Testing before and after the installation confirmed a drastic reduction in reverberation, from 1.5 seconds to 0.58 seconds.

This reduction resulted in a significant improvement in the perceived acoustic environment in the space. When previously conversation was strained, it was now smooth and neighbors had little difficulty understanding instructions and dialog.

Overall, the project took 3 weeks to complete, and the turn-key solution was provided at under $11,000.

Wall Blokker vs Acoustically Enhanced Gypsum Board

Acoustically enhanced gypsum board, such as Quiet Rock or SoundBreak, is commonly used in the construction of high STC (sound transmission class) wall and ceiling assemblies. It contains a viscoelastic gel layer in the center which is sandwiched between two thin drywall layers. Uses include but are not limited to educational, healthcare, commercial and multifamily projects.

While they are ideal if space constraints are critical, there are other products that achieve a higher STC at a fraction of the cost if small footprint concessions can be made.

Soundbreak and QuietRock Alternatives

SoundBreak and Quiet Rock drywall does have its pros. They get hung like traditional drywall for a ‘fool-proof’ installation every time unlike resilient channel which has very challenging installation requirements. The material cost however is 5x more expensive than traditional drywall, and due to the core density, the weight of the product often causes increased labor costs from contractors. Whereas acoustical drywall is approximately 2 lbs per square foot, many EVA membranes are approximately 1 lb per square foot, and therefore much more easily maneuvered at height.

When analyzing cost and effectiveness, a strong VE (cost-saving value engineering) option for this product is a soundproofing membrane which would get hung on metal or wood studs underneath traditional drywall. Instead of paying a premium for a gel barrier within the drywall, installing both pieces separately will save substantial cost. The Wall Blokker soundproofing membrane combined with traditional 5/8” drywall will outperform acoustically-enhanced drywall by 3-5 STC points on the same assembly, roughly saving $1.70/sf vs. Sound Break XP. See data below:

Residence Inn Highway Soundproofing

A Residence Inn location was having problems with their guests complaining about highway noise in their rooms. The hotel had not done any acoustical testing nor treatment in the past, so it was not surprising that car noise would enter the rooms and disturb guests. This is often an overlooked problem by many hotels, including ones that are high-end. Since there are not many acoustical consultants offering either proper testing nor proper materials, most hotel managers are forced to tell their guests there is nothing that can be done to reduce noise in their room. However, there are simple solutions that are not only effective but also affordable for all types of hotels.

When we arrived at the location, we asked what rooms had the most noise complaints. We made our way to that area and started testing the acoustics. After we tested the sound coming into the room, we made our final analysis and came up with a solution for our client.

We realized the main problem for this hotel was the sound leaking through the windows. Our team recommended they hang soundproofing curtains over their windows to seal any noise “leaking” through cracks or small openings in the windows. Soundproofing curtains are made up of MLV (mass-loaded vinyl) which is designed to block unwanted noise by up to 75%.

After installing the soundproofing curtains, the noise coming in from the highway as well as noise complaints from guests were significantly reduced. By teaming with the client’s engineering and maintenance team, we were able to deliver a cost-effective solution within budget that has solved the majority of noise complaints that the hotel previously encountered.

 

Soundproof Your Smart Home

As the amount of technology and automation grows in new “Smart Homes” across America, there is another silent, growing problem – soundproofing. These homes are outfitted with 7.1 speaker systems, entertainment centers, in-home theaters, and even music studios. However, all of this technology integration can create a noisy environment that installation firms don’t always know how to address.

In these cases, a systematic approach to acoustics and soundproofing should be considered. Often-times there are 1-2 “critical” areas in the home that must be addressed above all others. Whether it is the source room (outlined above), receiving room (such as a Home Office or Master Bedroom), or flanking paths (outlets, ducts, etc.), the designer should consider the cost and schedule impacts of improving the STC or IIC ratings of the systems.

All acoustical designs begin with the Source-Path-Receiver approach to determine how best to treat the problem. It can be very cost-effective to soundproof a theater room with soundproofing membranes, for instance, but a shared ducting system between the two may limit the effectiveness of this approach. By beginning with a general approach, the designer may find multiple solutions, then down-select to the one that is most cost-effective.

Options available to designers include:

  • Improving STC performance of walls – all walls do not need to be treated equally. If the theater and master bedroom are completely isolated, then utilize more cost-effective approaches in other locations.
    • Staggered or double-stud walls
    • Soundproofing Membranes
    • Fiberglass or Mineral Wool insulation
    • Locating buffer areas (closets, pantries) around louder areas (AC units)
  • Improving IIC performance of floors
    • Using higher-IIC top floors, especially plush carpet
    • Using underlayments, especially under poor performers, such as hardwood or tile
    • Resiliently-mounted ceilings where possible
  • Treating Flanking Paths – perhaps most critical, especially in smart homes
    • Caulk all wall penetrations (ducting, pipes, etc.)
    • Use putty pads and caulk heavily around outlets on critical partitions
    • Use solid core doors with tight seals around the threshold and jamb
    • Use branch ducting that separates vents going to and from studios or other loud locations to other critical locations in the home

An experienced soundproofing designer and installation team will consider all soundproofing options, and implement the one that is most cost-effective and beneficial to the home owner.

Soundproofing a Smart Home

A new-construction custom home was being completed in Tampa, FL in February 2017. Outfitted with some of the most recent technology, the owner was concerned about excessive noise from the playroom and entertainment room upstairs, as well as insulating the Master Bedroom downstairs. The framing was made of 6” wood studs, with ceilings at 12’ and an isolated Master Bed-Bath suite.

After an initial site visit, we determined the ideal approach of implementing a soundproofing membrane directly to the studs downstairs, and completely isolating the master bedroom suite. Upstairs, the Wall Blokker PRO was utilized in the entertainment and playrooms to ensure the speaker system would not disrupt activity in other portions of the home. Our approach was consistent with general guidelines to soundproofing a smart home.

While the initial discussions also included membrane in a side room, we decided to remove the STC product at that location due to the flanking paths available in the doorways (a critical weak-link often overlooked in the soundproofing schema).

The smart home owner was also interested in soundproofing the 2nd story flooring system, since the footfall of children and visitors had been easily audible in previous homes. This was addressed by adding the Floor Blokker membrane directly to the plywood sub-floor upstairs, which was then covered with a hardwood top floor. While a resiliently-mounted ceiling was not installed downstairs, the membrane was still able to increase the estimated IIC in the system from the low-30s to approximately 45.

Overall, STC and IIC ratings for the home were improved at the most critical locations (and removed in locations where improvement was not necessary). Our team installed both flooring and wall applications in a single day, and returned the following day to Quality Check and ensure all installations met our strict standards.

Clean outlet cuts were made, wall-floor intersections caulked, and a debrief with the contractor performed to ensure proper installation of drywall and ultimately, superior performance of the system.

A soundproofing project of this magnitude should typically run about $3,000-$7,000, depending on the size of the home and number of floors. Since premium soundproofing membranes weigh approximately 1 pound per square foot, the logistics of moving large quantities up flights of stairs becomes time-consuming. Furthermore, wall heights and floor footprint must be taken into account to determine the required number of cuts and splices. Hiring an experienced team to design, install and/or inspect the soundproofing work makes the difference between a moderate improvement in sound attenuation and a major breakthrough!

Central Florida Hospital – Sound Study

Solving Hospital Noise Complaints

The management from a hospital in central Florida requested an assessment and potential solutions to improve their sound rating scores in their facility. Specifically, the intent was to study and improve the HCAHPS question of whether patients find their environment “Always Quiet at Night”, and the corresponding improvement in patient care quality.

Commercial Acoustics planned and executed an acoustic study on premises, and completed related research, to outline an appropriate mitigation plan for the hospital noise levels. All measurements in this sound study were completed with a Class 1 Sound Pressure Level (SPL) meter and included time- and spatial-logged data to determine exactly when and where the various noise sources are occurring. Furthermore, all events were classified by type, and any anomalies were noted.

By addressing the leading causes of sound and implementing a Noise Reduction Program, the hospital is on its way to delivering exemplary patient care in regards to sleep (in addition to other patient satisfaction metrics).

This is a problem that many, if not all, hospitals face – yet few address it comprehensively. A sound study is critical to isolate the source of each of the noise issues, then they are prioritized and mitigated individually. Many of the issues are addressed via behavioral change, while others may require architectural modifications. By implementing a mixed-approach, most hospitals may expect to achieve significant results within the first 3-6 months of a Noise Reduction effort.

Luxury Theater Soundproofing

Theater Soundproofing

One of the most ideal uses for soundproofing membranes is when low-frequency reduction is critical to the performance of a system. This is especially true with entertainment and industrial venues, where low-frequency noise is generated from equipment and amplified speakers.

A recent case study with a luxury cinema in Dallas, Texas serves as a prime example. The client required an STC of 65 for the wall performance, but more importantly, needed attenuation above 20 dB in the 50-80Hz range. This is difficult, if not impossible, to achieve with conventional methods, including multiple layers of drywall on double metal-stud walls.

With gypsum-only assemblies an STC of 65 may be reached, but the attenuation (transmission loss) at 50 Hz is often around 8-12 dBs. Furthermore, this data point is not factored into STC performance, since STC only incorporates performance between 100-4000Hz.

Instead, we worked with the client’s architect to implement a hybrid solution with 1 layer of drywall on each side, and 1 layer of membrane applied directly to the studs behind the drywall. We used the INSUL software to model the system, and determined that this should provide a significant improvement in the low-frequency and broadband attenuation characteristics for the wall.

Once confirmed, we scheduled a test with Riverbank Acoustical Labs to run a custom test for this system, and received the results within 2 weeks. As expected, attenuation at the critical lower frequencies was 60-70% higher than the gypsum-only design. This is primarily due to the resonance of the wall, as the membranes provide a damping of the system while gypsum transmits sound energy through multiple layers if directly attached.

33 foot rolls were custom-produced and delivered to the job site to optimize the installation and maximize schedule recovery. Each roll was hoisted on the scissor lift and attached via 4 screws along the header track of the stud system. The lift was then lowered while the roll unspooled from the lift bar. This allowed the membrane to be installed at 3-4 times the rate of standard drywall.

The results were excellent – our client received a benefit in each of the cost-schedule-technical legs of the typical construction triad.

Cost: Significantly reduced drywall labor out-paced the increased cost of the soundproofing polymer membrane. Furthermore, the lighter-weight wall allowed further stud spacing, saving further material and labor costs.

Schedule: Since the drywall construction was on the critical path, it was essential to reduce it where possible. The membrane installed in each auditorium in less than 1 day, compared to 2 days for drywall. This allowed significant schedule recovery on the project that had been affected by inclimate weather.

Technical: Low-frequency attenuation was improved by 60-70%, especially in the “problem range” from 50-200 Hz. Furthermore, the STC was improved by 3 points overall.

Exterior Noise Control – Tampa Yacht Club

Yacht Club Acoustic Model

The Tampa Yacht and Country Club was struggling with an exterior noise issue. While it is a beautiful venue with a history of hosting elegant events, this also led to large wedding parties that sometimes were louder than local neighbors appreciated.

While the club (TYCC for short) hosted parties for years with little issue, a changing noise ordinance code in the City of Tampa was on a collision course for the Board of Directors. The traditional code required dBA and dBC thresholds at the property line, while the new code added in another requirement; that the noise was not “plainly audible” 100 ft from the property line. This code change significantly increased the concern for violations, so they contacted Commercial Acoustics to help.

The club had a challenge from the start, since their outdoor patio was a preferred venue, with unique tiled floors and open lawn. When the band set up here, there was excellent line-of-sight to all of the guests, but no borders or perimeters to attenuate the noise prior to reaching the property line.

An initial assessment was performed to quantify the existing noise levels, which occasionally peaked over 55dBA at the property line at night. Note that these measurements are made as 10-second averages, so that peak noise impulses do not automatically constitute a violation. Over the course of the evening, as the guests grew louder and the band amplified their music further, the noise issues sometimes grew worse.

Yacht Club Acoustic Model
Tampa Yacht Club Acoustic Model

It was clear that the club needed a 10dB reduction at the property line to minimize risk of aggravating nearby residents. Our operations team found a number of suitable locations to support sound-reflecting membranes on a nearby fence as well as supported directly from the overhanging tent. Meanwhile, our lead consultant modeled the effectiveness of this approach, and determined the expected sound levels at the property line after implementation.

Following a morning install (just before a wedding), the results were measured that evening, and found to reduce the noise levels by 15dB directly behind the venue, and 12dB at the property line. The Blokker panels were also hidden behind decorative sheer curtains so that guests weren’t even aware they were there.

Fence Blokker Panels
Fence Blokker Panels
Acoustic Measurements
Acoustic Measurements at Property Line

Further operational suggestions were made to club management, including loudspeaker control processes and re-orienting the stage.

The TYCC executed the option to purchase the membranes after the initial rental period, and have used them in the field since with excellent results.

The issue that the Tampa Yacht and Country Club faced were not at all unusual from what many of our clients deal with – unexpected noise problems that arise with unique constraints, and that often require unique, but cost-effective, solutions.

Historic Fenway Hotel

Fenway Hotel Soundproofing

Initially opened in the 1920s, the Fenway hotel is due to be reopened later this year as a boutique hotel. While the transformation included cosmetic and functional upgrades, there was one portion of the hotel renovation that called for soundproofing expertise – the noise transfer between rooms.

Construction technology has come a long way in the past century, and with it have come benefits of additional privacy and comfort. Adding sound-blocking layers in a historic hotel, with limited space already, proved to be a real challenge. As we’ve discussed in previous articles, resilient channel can be a feasible solution on wood stud construction (which includes the Fenway), but in this case, the architecture firm couldn’t afford the extra several inches per room (not to mention the installation concerns).

The construction consisted of 2”x6” stud walls with immediately adjacent rooms, leaving limited options. Our team of acoustical consultants reviewed the geometries and target STCs, and provided our solution – Wall Blokker PRO on each side of the assembly, with Floor Blokker on the wood joist flooring systems. Within weeks, our team installed the solution and tested it for effectiveness. While the confined space limited the STC performance, we were able to surpass an STC of 50 at a cost-effective price.

The Fenway is a new type of clientele that is relying on Commercial Acoustics to provide a soundproofing solution on budget, within schedule, and to soundproofing levels that were previously unavailable with conventional construction techniques.