When it comes to Direct Field Acoustic Noise Testing ('DFAT' or 'DFAN Testing') – and especially regarding large-scale acoustic tests - the details of the system design, performance, and operational execution are critical. But in a marketplace where new startups often tout ambitious promises, one key differentiator remains—proof of performance. At MSI DFAT, we have conducted over 230 DFAN tests, and our results are not just a claim—they are documented, verifiable, and visible.
Weight Considerations: The True Cost of Clunky Designs
One of the significant challenges with DFAN testing is the weight of the equipment. Large, bulky speaker enclosures can place substantial load on host facility floors, often requiring extensive structural engineering to ensure the flooring can withstand the pressure. This is especially true for larger tests where the noise generation system’s weight can easily exceed multiple tons.
To solve this issue, MSI DFAT’s MP™ series Noise Generation Systems (NGS) are designed to be significantly lightweight and modular. In addition, each speaker stack has 8 feet to distribute a smaller load at each foot. To date, we have never caused damage to a host facility due to the weight of our test setup. Our speakers weigh just 300 lbs each, compared to much heavier units typically found in larger systems, which can weigh over 1,617 lbs per unit. For large-scale deployments, this results in far less weight and reduces costly structural assessments and related risks. Additionally, the reduced weight improves logistics by cutting transportation costs and reducing environmental impact, with fewer trucks, less fuel, and a smaller carbon footprint.
Tip-Over Risk, Weight Distribution, and Structural Integrity
Another key consideration in DFAT is the stability and structural integrity of the speaker stacks. In setups where heavy, bulky units are stacked, ensuring that the system remains level as height increases is critical, especially for tall configurations that can exceed 40 feet in height. MSI DFAT addresses this with practical orientation tuning systems at the base of each speaker stack to ensure stability and leveling, even in tall vertical setups. These systems are further reinforced by cross-bracing to ensure structural integrity, reducing the risk of tip-overs during testing. MSI-DFAT provides structural stability calculations for every test based on seismic rating for their location.
Another key design of the MSI DFAT’s MP™ series Noise Generation Systems (NGS) is the deliberate use of precise and tunable leveling “feet”, and increasing the floor-contact surface area by doubling the number of feet under each stack. It's essential to understand the inherit risks poised by insufficient and dangerous design approaches that do not use proper base-frame bracings, supports, and adjustment mechanisms, especially as vertical height increases.
MSI DFAT’s lightweight Noise Generation System (NGS) uses precise leveling system at the base of each speaker stack to ensure that speaker stacks remain perpendicular with respect to the flooring, especially when stacked up to significantly tall vertical heights. Remaining level as vertical height increases in the acoustic test setup is a serious consideration, especially for tests surpassing 30 or 40 feet tall. For a 32’ speaker stack, just 5 degrees from level reduces the righting force 6%.
Alternative design approaches that do not use tunable or adjustable “feet” under the speaker stacks, and simply adding heavy and clunky units on top of each other, presents a serious concern for structural integrity and the possibility of tip-over onto mission-critical and expensive spacecraft. This is a serious risk that no company should consider or allow, especially if a host floor is not level. Imagine a huge stack of thousands of pounds of loudspeakers falling on top of a spacecraft, simply because the floor was not level, and proper support systems were not used! This risk is increasingly important in higher seismic activity zones.
Stacks of MP™ series speaker remain level as vertical height increases thanks to the base frames with purpose-built adjustable leveling and tuning systems. Further reinforcement is provided by cross-bracings to ensure structural integrity and to avoid tip-over, especially in high-seismic zones.
It’s critical to recognize that weight distribution is only one factor in the successful deployment of DFAT systems. Acoustic coverage, uniformity, and performance over distance are equally important. MSI DFAT systems are known not only for their lightweight design but also for their ability to deliver consistent, high-quality sound across large test areas with uniformity and diffusivity in both the horizontal and vertical domains.
Space Efficiency: Tailored-Fit To Your Testing Needs
Large-scale DFAN tests often occur in space-constrained environments. Alternative systems use bulky, large cabinet enclosures that take up significant available floor space. This can be a challenge in facilities where space is limited.
MSI DFAT systems, in contrast, utilize modular, space-efficient configurations that deliver superior performance while occupying less total physical space. This allows us to perform high-intensity tests in a wider range of host facilities, making our solutions more adaptable and cost-effective. Our MP™ Series Noise Generation Systems (NGS) are proven to deliver at least 1/3rd less space than alternative systems, while providing better acoustic performance.
Safety: A Comprehensive Approach
Safety during DFAN testing is paramount, and while weight distribution is one aspect to consider, it’s not the entire picture. Real-time system monitoring, vibroacoustic control, narrowband MIMO control and response limiting, and automated shutdown protocols are also relevant factors that impact total test safety.
Safety also requires advanced engineering and precise management of the testing environment. Environmental conditions, signal integrity, and system redundancy also play vital roles in ensuring that a test is not only safe, but also reliable. Only the Direct Field Acoustic Test setup provided by MSI DFAT adequately addresses all these key areas.
Cleanliness and Cosmetics: What Truly Matters
While cleanliness is crucial, particularly for tests in controlled environments like clean rooms, it should never overshadow the core function of the system—delivering high-quality, reliable testing. We’ve heard several anecdotes about beer and coffee spills and dust accumulation occurring on alternative vendors systems while being displayed at industry trade shows. If the same unit was then packaged, covered in plastic, unwrapped, and subsequently used at a customer test facility, the dust, coffee grinds and debris would fly out of the noise generation unit and land on the highly-sensitive spacecraft under test. AIT engineers understand the importance of cleanliness in test environments, and this level of contamination should not be tolerated. It's one reason why MSI DFAT has clean, dedicated facilities and trucks used to store, maintain, and transport our purpose-built DFAT speakers.
Simplicity vs. Customization
MSI DFAT systems are designed with simplicity in mind. Each MP™ series speaker connects through a single cable, allowing for quick setup and streamlined operation. This simplicity doesn’t mean we compromise on flexibility. Instead, our Noise Generation Systems can be easily custom-configured to meet the specific needs of each acoustic test. Every DFAN test is unique and requires a tailored setup to accommodate the facility, the test article, and the specifications of the acoustic test.
Each MP™ series speaker connects through a single cable, allowing for simple setup and streamlined operation.
Real-world DFAN tests are rarely straightforward. The flexibility to customize the acoustic testing system for various noise test environments is critical. MSI DFAT excels because we understand that one-size-fits-all approach doesn’t work for complex acoustic testing. A non-modular system is not able to meet the varying demands of widely differing test conditions. This is why we separate out our NGS by frequency ranges of interest. MSI DFAT uses speaker configurations tailored for each unique spectrum. Often the spectrum has increased low or high frequency requirements beyond standard encapsulated spacecraft levels. As required, we add more standard speakers or use smaller band focused speakers.
Team Expertise: Experience Matters
Another area where MSI DFAT stands apart is in our experience. Having conducted DFAN tests for over two decades, since 1999, MSI DFAT holds the record for the most time spent conducting DFAN tests. This sheer volume of experience, over 100years combined, ensures that our engineers are not only adept at managing tests but also capable of quickly troubleshooting and optimizing under high-stakes conditions.
Clients that work with MSI DFAT can be confident in the knowledge that they are partnering with a team that has performed multiple hundreds of tests and holds world records for DFAN test height and intensity.
When choosing a partner for DFAN testing, it’s essential to look beyond surface-level claims. Weight distribution, environmental impact, and team expertise are all important factors, but they must be considered alongside performance, flexibility, and safety. MSI DFAT stands out not only for our long-standing track record and world-record achievements, but also for our ability to balance efficiency with sound fidelity, customization, and real-world applicability.
Launching things into space?
