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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.
Project: Richmond Friends Retreat Center
Posted by Acoustics First in Absorption, Media Room, Multipurpose Rooms, Product Applications, Products, Worship Facilities on October 26, 2023
Earlier this summer, Richmond Friends Meeting reached out to Acoustics First® for assistance with their new Retreat Center in Amelia, VA. Their multi-purpose community hall was overly live with reverb and echoes, contributing to a poor listening environment. As this space is used for worship, meetings and social events, speech intelligibility is very important and more control was needed to “reign-in” excessive noise.
To correct these issues, Acoustics First® recommended a combination of 1” Hi-Impact Sonora® Wall Panels and 2” Sonora® Ceiling Panels. The acoustic design utilized “staggered” 2’x6’ ceiling panels to maximize coverage, in addition to the custom-shaped wall panels which match the slope of the ceiling.
With approx. 400 SQFT of panels between the wall and ceiling, reverb was reduced by approx. 50%, drastically improving speech intelligibility and general room comfort.
The treatment tamed the acoustics of the room, which improved speech intelligibility by reducing the reverberance… and they were very happy with the result!
Similar, Yet Different: Aeolian® vs. MiniAeolian™
Posted by Acoustics First in Broadcast Facilities, Home Entertainment, Home Theater, Media Room, Multipurpose Rooms, Music Rehearsal Spaces, Music Tracking Room, Product Applications, Products, Recording Facilities, Recording Studio, Studio Control Room, Uncategorized, Vocal Booth, Worship Facilities on September 28, 2023
In this installment of “Similar, Yet Different”, we are going to compare the two current variations of the popular Aeolian® Diffuser – the original 2’x2′ Aeolian and the 1’x1′ MiniAeolian™!
Design
This comparison has some similarities to the very first “Similar, Yet Different” post we made comparing the ArtDiffusor® Model C to the ArtDiffusor® Model F. We are looking at a diffuser that uses identical mathematic functions to create the shape… both the Aeolian® and the MiniAeolian™ are an “Organic Quadratic” constructed from a Bicubic Interpolation of a Quadratic Residue Function. They are both truncated so that they are completely asymmetric, even to the edge. The MiniAeolian™ IS an Aeolian®, only it is scaled differently.
You may recall that the Model F was constructed of 4 scaled down Model C diffusers in a monolithic 2’x2′ tile – This is not the case with the MiniAeolian™. The Original Aeolian® Diffuser is a 2’x2′ footprint that is 5″ tall, and will fit in a standard 2’x2′ ceiling grid. The MiniAeolian™ is a single scaled down unit, and it is a little different – The 1’x1′ footprint stands alone as a single unit, but it is only scaled down in height to 4″.
In this case, form follows function. The MiniAeolian™ was built to fill a specific function as a smaller wall-mount unit, or a direct-mount ceiling unit for smaller spaces. Part of this wall-mount function was to have a version of the Aeolian® that would fit in tight areas or in spaces that didn’t have enough clearance for the 5″ standard Aeolian® (or would require modification to those areas (or diffusers) to allow this extra height). Some people implement configurations that have tighter footprint requirements, and the 1’x1′ footprint of the Mini allow it to be used in these types of layouts.
Performance
So how does this change affect the performance of the unit? Surprisingly, they are quite similar. The Organic curved design, with only a 20% reduction in height, shows only minor differences in performance of their overall frequencies ranges – with both primary ranges starting at about 1500Hz-1600Hz with and average between 150° and 170° of horizontal and vertical dispersion up to between 5Khz and 7Khz. While the primary range is a good indicator, when we look at the actual polar response, we can get a better picture of their full range performance.
A quick glance shows two very similar performing diffusers, except for the low-frequency performance. The larger elements and deeper formfactor of the original Aeolian® are more effective at the 1000Hz range, where the MiniAeolian™ appears to be mostly specular. There are some surprises however. It appears that at the 2000Hz range leans slightly in the favor of using 4 MiniAeolians™ in an array verses the single Aeolian®. There is more surface variation over the same footprint (2’x2′ in the array of 4), and the size of the Mini’s features are a bit more optimal for diffusing the 2Khz wavelength. This swings back slightly into the favor of the single Aeolian® at 4Khz, where the larger elements have a wider throw, and the elements of the Mini have steeper wells. At 8Khz, it tips back to the Mini, and then at 16Khz, they are both neck-and-neck.
The amazing similarity is that the variations are quite subtle through their entire effective ranges, and even quite a bit above those ranges. While there are slight differences in the performance of the diffusers when we compare the directly, these are really very minimal except for the low-frequency edge in performance of the larger original Aeolian®.
Closing
With the similarity of performance in the two diffusers, they can almost be used interchangeably – or even used together in the same environment to implement an aesthetic vision or add more randomness/variety to the diffusion in the space.
There are several occasions where you may require one over the other.
- If you need more 1Khz diffusion, you should add some 2’x2′ Aeolians® – as they perform better in that range.
- If you need to install diffusers that fit in a ceiling grid… you will also want to use the original.
- If you want the Aeolian® but need diffusers that will fit in a space that is less than 2’x2’x5″, you may want to go with the MiniAeolian™.
Currently the MiniAeolian™ is a custom order item only, and is subject to minimum order quantities.
Contact Acoustics First® for more information and pricing.
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