Posts Tagged acoustic diffusion
Acoustics First® is pleased to announce our latest creation: The Aeolian™ Sound Diffuser. In some ways a simplified version of our popular Art Diffusor® Model D, the Aeolian™ is the latest in our line of ‘Organic Quadratics’. Part of the Aeolian’s™ unique design comes from its use of “implied symmetry”. Although the edges are all asymmetric, the height variations are just subtle enough to create an illusion of symmetry when installed in a standard 15/16” grid, or spaced appropriately on a wall. The lack of a uniform edge also has added acoustical benefits in the way of “randomness”.
The development process for the Aeolian™ was similar to that of our ‘Model D’. Various 3D models were created and refined, after which we ran acoustical simulations. Once we settled on what we considered the optimum design for what we were going for, a full scale 3D model was printed for lab testing. With the ‘real world’ test results in hand, confirming our predicted results, we set about making the final mold, and this new diffuser was born.
The Aeolian™ Diffuser is class A thermoplastic, and 4 lbs. per unit.
Nominal size is 23-3/4” x 23-3/4” with a depth of 5.1”.
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
You heard right – with both ears! (or Eyes?)
The Acoustics First® simulations took a huge leap forward toward more accurately modeling real world acoustic environments in two important areas.
- Ability to simulate Two sources (Now in Stereo!)
- Modeling Absorption to strategically remove energy from a space!
These two additions to the Acoustics First® simulations allow a vast improvement to the modeling of acoustic field development – and, while still in the early development stages, has already been instrumental in advancing the development of systems and products to improve acoustics in numerous ways.
See for yourself: In this most recent simulation, we compare the development of the acoustic field in two spaces with identical stereo sources – one room is basically a concrete box, while the other is a concrete box treated with absorbers and diffusers.
Untreated vs. Full Treatment Room Sim (Two Channel – With Absorption and Diffusion!) from Acoustics First®.
- Absorbers at early reflection points (Note Early reflection in First room)
- Diffusers breaking up specular reflections
- Absorbers constantly removing energy from the space – greatly reducing the overall intensity over the span of the simulation.
- This simulation is only modeling .046 of a second!
We hope you find this informative and stimulating and we will continue future developments of these simulations and try to add more functionality and realism to help all those out there to better be able to visualize the different ways you can affect the acoustics of a space.
For some of our previous Simulations – Click Here!
For anyone new to the world of acoustics, there is a multitude of terms, coefficients and numbers that are thrown around. This flood of information can seem intimidating, especially to beginners. In this series, acoustician Cameron Girard of Acoustics First® hopes to help you distinguish between what’s useful and what’s not.
Part 2: How Mounting in Testing Affects Sound Absorption Data
As I discussed in my previous article, the best way to compare the performance of sound absorbing panels is by referencing the Sound Absorption Coefficient (SAC) and Noise Reduction Coefficient (NRC). However, these coefficients are often used as marketing tools. Be on the lookout for companies that list absorption coefficients and NRCs without mention of a particular testing standard or mounting method. It’s vital to check for this information, as direct comparisons to competitors and other materials can only be made if their testing procedures are the same.
The sound absorption of a material that covers a flat surface not only depends on the physical qualities of the material but also on how the material is mounted during installation. The mountings specified in laboratory tests are intended to simulate conditions that exist in normal use, such as direct wall mounting and installation into a ceiling grid.
Many materials for treatment of walls or ceiling are tested using what is called Type ”A” mounting. Type ”A” mounting means the test specimen was placed directly on the test surface of the reverberation chamber. Lay-in ceiling tiles, on the other hand, are often tested using ”E400” mounting. The ”E” designates a sealed air space behind the specimen (simulating the air gap between a dropped tile ceiling and the structural ceiling) and the number after the ”E” is the depth of the airspace in millimeters. The airspace behind the acoustic material affects the sound absorption by acting as a bass trap. The deeper the cavity behind the panels is, the lower the fundamental of the “trapped” frequencies will be.
To see what this look like in terms of actual numbers, let’s take a look at how different mounting methods effect the sound absorption coefficients of Acoustics First’s HiPer® Panel (a low-profile, composite absorber/diffuser panel).
Since the HiPer® Panel can be used effectively in multiple applications; we had it tested in accordance to the two most-common mounting procedures, Type E-400 and Type A. The results of the laboratory tests are as follows:
Sound Absorption Coefficients
|1″ HiPer® Panel||1″||E-400||0.43||0.28||0.51||0.76||0.99||1.10||0.65|
|1″ HiPer® Panel||1″||A||0.09||0.28||0.78||0.75||0.94||0.85||0.70|
As you can see from the chart, the sound absorption coefficient at 125 Hz varies greatly between E-400 mounting (SAC of .43) and Type-A mounting (SAC of .09). If mounting the HiPer® Panel in a ceiling grid, with a sizable airspace, you can expect significant low-frequency absorption, but mounting it on a wall (Type-A) will result in much less absorption at 125Hz.
Other mounting methods are available, but are not used as frequently. Here are some of the basic mounting designations (See ASTM E795 for more information.)
Type A mounting – Test specimen laid directly against the test surface (wall panel on drywall).
Type B mounting – Test specimen cemented directly against the test surface. Type B mounting is intended to simulate acoustical ceiling tiles or other sound-absorptive products adhered to a hard surface with an adhesive.
Type C Mounting—Test specimen comprising sound-absorptive material behind a perforated, expanded, open facing or other porous material.
Type D Mounting—Test specimen mounted on wood furring strips.
Type E Mounting—Test specimen mounted with an air space behind it (dropped tile ceiling).
As we’ve discussed, acoustical data can vary greatly depending on the mounting method used during testing. Acoustics First tries to include as much information about testing procedures as possible, because we feel an informed client makes the best client.
Contact Acoustics First for your all your sound control needs!
Acoustics First® has long been at the forefront of many exciting developments in the world of sound diffusion. In the spring of 2015, we created a method to evaluate sound diffusers using particle computer simulations. Then we utilized 3D printing technology to streamline the development of new diffuser prototypes. Recently, we received a patent for our innovative Art Diffusor® Model D design. Now we’re excited to announce the release of a new comprehensive data booklet for our entire line of sound diffusers!
In essence, this booklet represents an entirely new way to view and compare sound diffusers. “With technological advances accelerating at a staggering rate, we believed it would be advantageous to compile all of the measurable acoustic parameters of these devices, in order to develop an operating profile for each.” Since sound absorption and sound reflection can both be measured with great accuracy, we foresee a use for this data, or similar data, in virtual acoustic room modeling, along with other useful applications.
Contact us for your own print copy of the Acoustics First Diffuser Data booklet (or click here to download the PDF). The electronic data that was used to create the polar diffusion balloons is also available per request (Data compiled for Acoustics First by NWAA Labs in Elma, WA).
Currently, we are working closely with other members of the industry in an effort to develop a universally accepted standard for testing sound diffusion. In the absence of such a standard, Acoustics First is presenting this data in good faith as we believe it represents the best of what is currently available.
We look forward to sharing more advances in the field of sound diffusion!