With all of the challenges of 2020, Technologies for Worship Magazine wanted to discuss the issue of acoustics in the current state of things. They approached Acoustics First® for help. While focusing on streaming, the article also covers other emerging issues and future challenges as we all move forward.
To overcome your present and future acoustic challenges, contact Acoustics First® for help!
When the Unity Spiritual Center of Woodstock wanted to use their sanctuary for more varied community events, it became apparent that they needed to address the acoustics of the space to meet the demands of those functions.
Acoustician Cameron Girard ran reverb calculations and provided a comprehensive treatment proposal utilizing Sonora wall panels. Sonora panels are a great solution for worship and performance spaces, offering excellent broadband sound absorption in an attractive, customizable finish. In addition to controlling the specular wall-to-wall reflections (echoes) which degrade speech and music, the recommended treatment aimed to reduce excessive reverberation by approx. 50%, significantly improving intelligibility. Cameron’s clear panel layout facilitated a simple installation that was performed by handy volunteers from USGW’s congregation.
Sonora Panels tamed reflections from the back wall and lowered the overall intensity. This increased clarity while keeping the ambiance that the congregants enjoyed. Acoustic changes that tame a space don’t need to destroy its acoustic character… they can be focused to manage some of the elements that produce unwanted artifacts.
The front of the room received some more Sonora Panels, but reinforcing surfaces from the ceiling were left reflective to allow any unamplified voices from the stage to carry into the audience.
Now a full year removed from this project, How did it turn out?
”The sanctuary at the Unity Spiritual Center of Woodstock turned out beautifully both visually and acoustically. The folks at USCW are very pleased and the old sanctuary now has new life with more activities and recognition from the community as a great new venue for many things both church and community based including concerts and stage productions.” – George Muligano USCW
Another Happy Client!
Reach out to Acoustics First for a treatment recommendation for your performance space or worship facility!
While these two diffusers look very different, there are a fair amount of similarities between them. Their physical size and depth allow them both to be great mid-frequency diffusers, but did you know that the Aeolian® started life as a blocky-looking diffuser – just like the Model C? It’s true!
The mathematics behind the two diffusers is similar, but the implementation is different. While the Model C retains its “blocky” appearance, the Aeolian has run through a mathematical process called “bicubic interpolation.” Without turning this into a math-heavy post, if you take a “blocky” design like the Model C and run its geometry through bicubic interpolation, you get a “curvy” surface like the Aeolian® – It “smooths” the transition from one block to the next in a 3 dimensional matrix.
While they did not begin as identical geometries, they were similar in their height ratios – with the Aeolian® starting with fewer blocks in a more random distribution, and a slightly taller maximum height. They both effect similar frequency ranges, with the Aeolian® going slightly lower and higher due to its depth and interpolated surface. The pattern and type of the diffusion is also different because of the different geometries – the Model C has blocks, and the edges of those blocks introduce a great deal of edge “diffraction” – which is what happens when a wave interacts with an edge, or corner, of a surface. It bends and shears around the edge, which helps break up the continuity of the waveform, where the Aeolian® takes the approach of redirecting most of the energy off a randomized and continually-curved surface.
It is important to note that the two are similar, yet different in their absorption numbers as well. With the Aeolian® being deeper with a single large cavity, it provides a bit more absorption in the low frequencies than the Model C, which is a more rigid geometry containing smaller elements. Depending on the space, this may be a useful addition to the diffusive properties. While some spaces need the extra absorption, some are pretty well balanced already and are just looking to “sweeten” the sound a bit.
On the surface, they are both a nominal 2’x2′ square of thermoformed Class A plastic with lightly textured surface. That is the extent of the visual similarities, and we cannot hide the aesthetic differences between the two devices. The ArtDiffusor® Model C is a “classic” diffuser. Many have been looking at these for the better part of 3 decades now. It’s a classic design at this point with no need for introduction – it is what the quintessential diffuser “looks” like. In fact, when many people think of a diffuser – the Model C is what they visualize! The Aeolian® is a modern rendition of the classic design. Using modern calculation techniques, we can now present the type of diffusion the Model C is famous for, in a different way.
While the two geometries look entirely different, and perform a bit differently, they have a common heritage as mathematical, 2-dimensional diffusers. You could say that the Model C is the grandparent of the Aeolian®, and that pedigree has been passed on – having a similar foundation, but a different final interpretation.
AudioXPress turned to Acoustics First® for their “Focus on Acoustics” Edition (August 2020), to help shed light on what test data is – and what it isn’t. Many people rely on lab results when trying to find products that meet design criteria… but there are limitations to this data. The “Elephant in the Lab” is that there is no such thing as absolute, repeatable, accuracy in lab tests… and this article brings to light why that is, and why it will likely always be the case.
It also addresses the impact this has on calculation accuracy, simulations, and what is being done to address this issue.
We often get asked about the functionality of the different diffusers, and one of the frequently asked questions is about the differences between the ArtDiffusor® Model C and ArtDiffusor® Model F. We will cover some of similarities and differences in the design, functionality and use of these two devices.
The Model C and Model F use identical math to come up with their basic structure, they even have angled faces – the main difference between the two is that the Model F elements are ½ of the Model C’s height, length and width – and then it is duplicated 4 times in the same footprint… The Model C is nominally 2’ x 2’ x 4” deep. The Model F is four quadrants that are nominally 1’ x 1’ x 2” deep – like little scaled down Model C’s… This makes them visually similar and aesthetically compatible. This low profile design makes the Model F more desirable for ceiling installs in spaces with very limited headroom – like basement studios that have low ceilings.
Due to the different size of the elements on the two devices, they have very different frequencies at which they are most effective. The Model C is a mid-frequency diffuser by design… having larger elements and deeper wells than the Model F. The Model F is primarily a high-frequency diffuser, due to the small elements and lower profile. Both diffusers are tuned to different frequencies as their “primary range,” and while they do affect lower and higher frequencies than they are designed for – it is to a lesser degree, or the product of absorption.
What does this mean?
The Model C has a primary design range of 1KHz to 4KHz. This is where it is primarily designed to work. It can and does diffuse below 1KHz and over 4KHz – just to a lesser degree than its primary design range.
The Model F has a primary design range of 2KHz to 8KHz, and again, it does diffuse outside of that range, but to a lesser degree.
The angled caps of both the Model C and Model F help to extend their high frequency range by reflecting sound in different directions at higher frequencies – causing the sound to scatter spatially. The different heights of the elements cause sound reflections to be offset “temporally,” or in time. The sound that hits the higher elements is reflected sooner than the sound that hits the lower elements – travelling further before it is reflected. This time offset, changes the “Phase Coherency” of the reflection; the larger the difference in the heights, the greater the offset in time.
The size of the elements matters as well. The shorter wavelengths of high frequencies can diffract and scatter off of the smaller elements of the Model F more readily than low frequencies, which see the Model F as a slightly angled & mostly flat surface. However, the lower frequencies are more affected by the larger and deeper elements of the Model C.
How do these differences help define their use?
The Model C is a great all around diffuser – it covers a wide range of frequencies, throws a very predictable 2D diffusion pattern, and it is tuned to a very musical range.
The Model F is a great high-frequency diffuser. It targets a few very specific, yet important issues. High frequencies are responsible for some nasty problems in rooms. Flutter echoes, ringing, comb filtering, and other artifacts are particularly noticeable in higher frequencies. If your room is otherwise performing well acoustically, the Model F can help tackle that last hurdle to make a good room into a great room.