St. Andrew by the Bay – Custom HiPer® Impact Panels to absorb and diffuse sound!
Posted by Acoustics First in Absorption, Diffusion, Product Applications, Worship Facilities on April 10, 2024
St. Andrew by the Bay is a traditional worship facility with a focus on spoken word worship and congregational singing. The large volume and hard surfaces in this space are the physical features most at fault for excessive reverberation, comb filtering and distracting “slap” echoes (discrete sound reflections usually caused by a distant, reflective back-wall).
To correct the slap-back and curb excessive reverb without “over deadening” the space, we recommend distributing approx. 550 SQFT 1” HiPer® Impact absorber/diffuser panels throughout the rear wall areas (see attached layout). HiPer® Impact panels absorb low frequencies and diffuse high-frequencies, yielding a much more even room response. In addition to controlling bass buildup, the high-frequency scattering will help retain some “life” in the room for acoustic and choral performances.
Reverb Prediction – Historically, churches relied on an abundance of hard surfaces to propagate sound to the rear of the nave, so they benefited from very long reverb times (upwards of 4-5s). Modern sound systems allow for a much more focused sound and equitable listening environment , so these extreme reverb tails are no longer necessary and can actually degrade the experience of the congregation. Churches of this size with a sound system and traditional worship services should have a reverb time somewhere in the 1.5-2.25s range. We entered the sanctuary’s dimensions and construction materials into our acoustic calculator and made a prediction of reverb times before and after treatment.
From Lee Hartman & Sons who performed the install “Here are some photos of the finished panels at St. Andrew by the Bay. It turned out great and client is very happy. Many thanks to Cameron for the detailed layout.”
Before & After: Video Conference Room
Posted by Acoustics First in Absorption, Customer Feedback, Media Room, Multipurpose Rooms, Offices, Product Applications, Products, Teleconferencing, Video on March 6, 2024
AMC Technology is located in a 5,400 square-foot suite that features a large open office area, a break room as well as several conference rooms.
When Acoustics First® initially met with the AMC team, they had recently moved into the space and were experiencing a number of acoustic problems in the open office area. Although Acoustics First® originally provided recommendations to improve workstation isolation in the open office, once the employees settled into the space, call-clarity issues in the conference rooms had become the much larger concern.
Three of the conference rooms were rudimentarily treated with 1” sound absorbing panels. The other four conference rooms were not treated acoustically and had hard/reflective walls, floors and ceilings. These hard surfaces were most at fault for excessive reverberation, noise buildup and distracting flutter-echoes (“ringing” caused by parallel reflective surfaces). These conditions contributed to an acoustically uncomfortable environment in which speech was hard to understand and conference call clarity suffered.
AMC Technology’s CTO, Anthony Uliano, identified a few goals for potential acoustic remediation. Anthony often works remotely and will call into the conference rooms to talk with team members. The sound of these calls on his side was frequently distorted and individual team members were difficult to understand. Anthony was concerned that clients were experiencing the same intelligibility issues. The primary goal for acoustic treatment was to improve the clarity of conference calls by reducing echoes and excessive reverberation within each conference room. Anthony also mentioned that they were experiencing some isolation problems. Though not a high priority, steps to reduce sound transmission were detailed for future consideration.
Acoustics First® specified Sonora® wall and ceiling treatment within each conference room to control flutter echoes and reduce reverberation down to suitable levels for conference calls. The video below provides a great snapshot of how the room sounded before and after treatment. Each recording is done in the same room, with the same employee and sitting the same distance from the microphone. The end result is a much clearer and intelligible conversation.
Project: Dogfish Head Brewing & Eats + Reading a Spectrogram
Posted by Acoustics First in Absorption, Customer Feedback, Product Applications, Products, Restaurants on February 12, 2024
Dogfish Head Brewing & Eats is a brewery, restaurant and performance venue located in Rehoboth Beach, DE. This largely reflective space has a wood ceiling, an un-polished concrete floor and walls comprised of drywall, unfinished wood planks (over OSB) and glass. These hard surfaces promote reverberation and early reflections, resulting in a noisy and “muddy” sounding environment.
Acoustics First and Integrity Sound Solutions were brought in to provide solutions to remediate noise level and clarity issues.
The co-owners of Dogfish Head Brewing & Eats and their house engineer identified a few goals for acoustic treatment…
- Reduce “background” noise as levels in excess of 85dBa were common on busy nights. Under these conditions, the sound engineer would push the sound system above 95dBA to maintain music intelligibility. This results in an acoustically uncomfortable environment for patrons and wait staff (which in turn elevate their voices to be heard, further exacerbating noise level issues).
- Control excessive reverberation and latent reflections to improve live-music clarity.
- Minimize visually obtrusive acoustic treatment, particularly on the main wood ceiling.
Acoustics First recorded numerous sine sweeps using the house system (JBL line array and subs) and a calibrated Zoom H4 recorder as the receiver. The sweep was recorded from a number of positions (in front of stage, main dining area, in front of the bar and from the mezzanine level). The following charts are spectrograms of two of these sweeps. Spectrograms are a visual way of representing sound intensity (volume) across a range of frequencies. We can observe how energy levels compare between frequencies and see the response of the speakers and the room at these frequencies over time.
The spectrograms of the sine sweeps show that the house system is very good at producing the full spectrum of frequencies, which gave us more confidence in our analysis.
Reading the Spectrogram – The thickest sweep line (furthest right) is the direct speaker output and the thinner sweep lines are harmonic resonances of the speakers; you’ll notice these bands get further apart as we move up in frequency. The thickness of the sweep, showing sound intensity over time, represents the extent of early reflections. For example, a sweep recorded in an anechoic chamber would have very tight lines.
The first 6dB of early reflections are the most distracting because of their intensity. Reflections arrive slightly late, but at the same frequency, create a “smear” of sound. The faster they decay (<100ms) the more focus you have on the direct source. As you can see, low and mid frequencies stay extremely elevated for the entire 100ms, resulting in a muddy, undefined sound.
Reverberation Time – Measurement & Analysis:
Reverberation Time (RT60) is a metric that is defined as the time it takes for sound to decay 60 decibels (dB) in a room. This is a very important metric for medium-to-large room acoustics as it dictates how well a room will perform for speech and music applications. Generally, a large room with abundant hard surfaces will have a long reverb time. Surfaces that have sound absorptive qualities, like carpet and acoustic panels, reduce reverberation.
Bars/restaurants of this size with live music should have a reverberation time below 1.2s, ideally in the .6-.8s range for “high-intensity” performances, like Rock, Hip Hop or Electronic Dance Music.
We recorded a balloon pop and the subsequent reverb tail and calculated the reverb time based on the decay rate. The results were as follows.
RT60 measurement of 1.656s was recorded at the center of the room. Although this measurement is shorter than initially expected, it is still excessive given the use of the space.
Reverb Prediction:
We entered the dimensions, construction materials and furnishings of the restaurant into our acoustic calculator and made a prediction of reverb times before and after treatment. The modeled “existing” reverberation time and the measured RT60 results we took on-site were very close @ 2000Hz, which gives us confidence in the acoustical model. This means we can add acoustical treatment to the model and accurately predict the results before any changes are made to the actual room and it shows how much improvement you can expect from the recommended treatment.
As you can see, the treated result in the model is within our target RT60 (.6-1.2s) for amplified live-music, resulting in a more suitable performance environment. This treatment would also significantly reduce noise buildup (in a well-treated room, customers and staff will not feel like they have to shout to be heard), further helping control noise levels.
To minimize the amount of visually noticeable treatment, Acoustics First specified fabric wrapped Sonora Panels (http://acousticsfirst.com/sonora-wall-panels.htm) and factory-painted Tone Tiles panels ( https://www.acousticsfirst.com/acoustic-tone-tile-panels.htm) to match the exact wall color. Acoustics First also recommend Sonora Blackboard https://www.acousticsfirst.com/sonora-black-board.htm to “fit” within the metal beams.
Most of the sound absorptive treatment was broad-band in nature. However, Low-Frequency Control (LFC) panels were utilized on the stage wall (behind the line array) to combat the early bass reflections that degrade low-frequency definition. LFC panels are a specialized absorber that focuses squarely on attenuating low-frequencies, below 250 Hz. View our website for more information – https://www.acousticsfirst.com/sonora-lfc.htm
As you can see from the pictures, Integrity Sound Solutions did amazing job with the installation.
What does the client think? Per the co-owners “The sound quality is exponentially BETTER…. The stuff in the beams just disappears!”
Similar, Yet Different: Model C vs. Model D!
Posted by Acoustics First in Diffusion, Home Entertainment, Home Theater, Media Room, Multipurpose Rooms, Music Rehearsal Spaces, Music Tracking Room, Product Applications, Products, Recording Facilities, Recording Studio, Studio Control Room, Theater on January 5, 2024
In this installment of “Similar, Yet Different,” we take a good look at two very different looking diffusers in the 2’x2′ size… the classic ArtDiffusor® Model C and the organic, rippled ArtDiffusor® Model D – while there are some similarities, there are some key differences in how they look (obviously) and how they perform.
Quick Similarities.
The ArtDiffusor® Model C and Model D are both 2’x2′ diffusers which are made to be either wall mounted or installed in a standard drop-tile ceiling grid. They are both formed from a Class A fire-rated polymer in a single piece. Both are mathematical diffusers, which create their different physical features in a “form follows function” methodology. They also cover roughly the same frequency bands, with some minor variation in how they execute their control.
Difference in Math
The Model C is an interesting configuration. Often you will see quadratic residue diffusers with flat blocks or wells in a relatively standard quadratic cell formula configuration. The Model C runs in a much different alternating binary configuration. The basic idea is that cells are placed in a 45° array with each cell adjacency calculated as an alternating array of higher and lower cells starting in the middle and working in a pattern of alternating low/high cell clusters decreasing toward the edges of the diffuser. These diffusers also do not have flat tops on the blocks – they are angled at 10°. The orientation is then rotated in 90° steps in a pattern that maximizes the spatial redistribution of reflected sound. This was a vast design departure over the original quadratic design, and created a diffusion profile that was distinctly different.
The Model D was an even greater departure. It began with a Maximum Length Sequence (MLS) concept that first changed the varied straight channels into rings of different dimensions. These rings then broke from the MLS mold by getting varied height profiles based on the QRD sequence. As if having different size rings at different heights wasn’t enough… the randomness was further perpetuated through a Boolean process of assigning certain rings a random property that would either add or subtract height from any other ring that they crossed. Finally, the entire surface geometry was smoothed using a bicubic interpolation, creating the organic undulating surface which gracefully spans the entire profile.
What this difference in math does to the acoustic performance.
The Model C has a nice even diffusion profile through it’s primary working range. This is a product of the QRD design and binary distribution. The set size for the blocks guarantees a solid primary frequency range from about 1KHz to over 4Khz. This tunes the Model C squarely in the most sensitive bands of the human hearing range. Below this range the device becomes a bit of an absorber. Above this range and the performance becomes more effective at intervals, which can be seen in the areas of wide diffusion at 6KHz – 18 KHz. These repeating zones are common in “stepped” quadratic designs. Due to the heights of the well being at specific intervals, the intervals repeat at octaves of their effective bands.
The Model D doesn’t have the same stepping. The spline interpolation and the random Boolean shifts smooth the transition from one quadratic height to the next, and the MLS sequence causes a bit of a high-pass filter pushing the start of the primary range to around 2KHz – which is a little higher than the Model C. The main difference is that once the Model D starts it’s range it diffuses everything up to and over 20KHz without the banding that can happen in other quadratic designs.
Another difference in symmetry.
The ArtDiffusor® Model C is a fairly symmetric design, but it’s 45° angle pushes that symmetry along the diagonal (corner to corner) across the unit. The asymmetry is subtle but allows for enough variation to account for any “lobing” issues that can occur in more simple geometric devices The 10° block faces being at varied orientations is key to increasing the spatial directivity over the older “flat-faced” Quadratics. This was a very novel design when it was first introduced, and those benefits are crucial to the longevity of the Model C’s reign – It just works. It’s predictable and musical… and that’s why it’s here to stay!
The ArtDiffusor® Model D is a completely different animal from the Model C when it comes to symmetry… as a matter of fact… there isn’t really much on it that is symmetric! The Model D was designed as a departure from symmetry. Focusing on the mid to high frequencies, which are very specular, the organic geometry creates an asymmetric reflection pattern. This pattern can be used to steer the sound into a wider field.. and that profile changes with the wavelength of the sound that hits it. This steering ability and the wide frequency range has made the Model D a favorite in mixing and mastering environments, where they can get smooth performance through the entire frequency spectrum.
How these differences benefit everyone.
We have stated before that there isn’t really a one-size-fits-all solution in acoustics. Many environments will use various treatments to achieve their desired goals. You will often have different devices to address different problems, in different frequencies, in different locations, in the same space. Bass traps for controlling the lows. Absorption to reduce gross energy across the board. Large geometric surfaces to break up parallel reflections and steer the projection of sources. Mid range diffusers to create clarity to the sources and reduce artifacts. High frequency diffusers to reduce flutter and add a feeling of envelopment and airiness in the space. These devices all have their place – from the smaller listening rooms, to critical listening environments, and large multifunction spaces and venues.
It is also worth noting that these two devices have a very different aesthetic visually. The classic blocks of the Model C have become a signature look for quality sound environments, and people recognize them as they would classic geometric pyramids and barrels. The Model D aesthetic provides a visual accent that people take advantage of to set their space apart from others. The undulating, asymmetric pattern changes drastically when you rotate the individual units in the array. This allows for not only varied acoustic performance, but also a unique visual possibilities – with numerous variations.
The ArtDiffusor® Model C and Model D are two tools that are used to craft ideal listening environments around the world… and in those roles they are indeed Similar, Yet Different.
The Pickle Factory
Posted by Acoustics First in Absorption, Customer Feedback, Fitness, Gymnasium, Product Applications on November 28, 2023
The Pickle Factory is a massive (22,500 SQFT) indoor recreation facility that was recently renovated to exclusively host pickleball games (previously used for soccer and basket/volleyball matches).
Pickleball utilizes hard paddles and hard-plastic balls, which result in loud “whacks” (upwards of 85dB) when the game is being played. With dozens of paddles active at once, the buildup from these hits can be deafening!
Sonora® Lite PVC Encapsulated wall panels were specified as they are extremely cost effective (approx. half the cost of fabric wrapped panels), offer decent sound absorption and can hold up to the occasional hit from a pickle ball. The monstrous volume of the Pickle factory necessitated covering a large portion of the available wall space to ensure a noticeable improvement.
Although sound absorptive treatment cannot work “magic” and reduce direct sound from the ball impacts, it can reduce overall buildup by as much as 6dB, greatly improving overall acoustic comfort.
From the Installer Lee Hartman & Sons “The client didn’t want the walls covered in sheet rock to get treatment even though it was spec’d in Cameron’s layout. Still got very adequate reverb reduction. Thanks, Cameron, for the layout. With some modifications, it worked out well as you can see. Client is very pleased with the result”
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