Posts Tagged art diffusor
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.
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.
We recently received these wonderful installation pics from our friends at Big3 Studios in Florida. They redid the back wall in one of their control rooms using our Aeolian® Sound Diffusers. In a couple of the pics you can also see our Model C & Model F Art Diffusors® (black) in the ceiling!
Back in the summer of 2015 we had a good time stuffing a bunch of our Model D Art Diffusors® into an empty storage closet and making a bunch of racket. The results were recorded, with the help of our friend Binaural Bob and the resulting data provided some interesting insights.
Well, Binaural Bob is back! This time we had a larger room than before (10’x9’x8’), and experimented with wider variety of sounds and treatment options. While this is obviously not the same as a controlled laboratory test, it does have a certain ‘real world’ flavor that’s relatable.
For best results, turn off any compression/effects and listen on headphones.
Reference Sounds played through speaker
Ye Olde Balloon Pop Test! (Calibrated 12″ Shiny Red Latex Party Balloons!)
WARNING! BALLOONS ARE LOUD – TURN IT DOWN!
Nick Lane, an independent audio engineer whose credits include Rascal Flatts and Reba McEntire, contacted Acoustics First® seeking help with his project studio. This process would convert the bonus room in his house (a second floor space above his garage) into a Project Studio.
After receiving some measurements and photos, we went to work designing a layout for the space.
Placement of panels and ceiling clouds were optimized to reduce early reflections and trap bass, and a combination of Model D’s and C’S were used to widen the “sweet spot” of his room.
“Sounds really good!….. High end is sooo much less harsh…… walking around the room, the low-end doesn’t disappear in places anymore” – Nick Lane