A Test by Any Other Name: Confusion & Clarity for Direct Field Acoustic Testing Terminology

Cross-points between Shakespeare and space are few, but many of our Direct Field Acoustic Testing customers find themselves asking the same question that Juliet famously asks in Shakespeare’s Romeo & Juliet, “What’s in a name?” Many customers are confused because the practice of using loudspeakers to create controlled acoustic environments has existed since the early 1990s, yet it has adopted various acronyms for the test methodology known as Direct Field Acoustic Testing.

Backstory

Going back to the 1990s, when using loudspeakers to perform acoustic testing was first studied and attempted, one of the earliest references to the method is the term “Direct Acoustic Testing.” Although earlier references indicate initial efforts to validate loudspeaker-based testing as a methodology, the approach was still developing and lacked a unified name that the aerospace industry could agree upon.

The early 2000s, almost ten years after the test approach was invented, is when we started to see references in published works to Direct Field Acoustic Testing. Building off the early work of Paul Larkin, a long-time advocate of the method, the acronym DFAT started to appear in various industry publications as an acronym for Direct Field Acoustic Testing. This acronym even went so far as to be included in NASA’s early studies on the test method, which led to the eventual publication of the NASA-HDBK-7010 for Direct Field Acoustic Testing.

While the publication of a NASA handbook on a test methodology indicated a usable reference had been achieved, it also marked an inflection point where things started to get confusing for our industry.

Confusion

In 2011, with NASA’s work to qualify and standardize Direct Field Acoustic Testing already underway, an application was filed with the US Patent & Trademark Office that would trademark the acronym “DFAT,” ensuring it could only be used by the trademark owner. Following the trademark’s approval in 2012, any other use would be at risk of legal repercussions. By the time the NASA Handbook 7010 for Direct Field Acoustic Testing was released in 2016, it made liberal use of the acronym “DFAT.” But as a result of the trademark filed in 2011, others in the industry could not use the term “DFAT” without risking legal action.

Consequently, confusion began to arise in the marketplace. To support the need for Direct Field Acoustic Testing in Europe, while still maintaining compliance with the trademark filed on the acronym “DFAT,” Siemens entered the market with a solution for Direct Field Acoustic Testing with the acronym “DFAX,” standing for Direct Field Acoustic Excitation. Additionally, as adoption of the Direct Field Acoustic Testing method grew and new policymakers entered the conversation, it became clear that a neutral acronym was needed to ensure that the broader community could join in the discussion around Direct Field Acoustic Testing without the risk of legal action being taken against them.

While its origin is not clearly marked in time, the acronym “DFAN” for Direct Field Acoustic Noise Testing began to enter the aerospace community and see wide publication in the 2010s. This allowed a wide range of end-users, service providers, and industry policymakers to have a standard reference point for talking about Direct Field Acoustic Testing, “DFAN.”

Today

In recent years, companies such as Siemens and Acoustic Research Systems have standardized on the acronym “DFAN” to describe Direct Field Acoustic Testing, while agencies such as ESA have moved in this direction as well, with the hopes of unifying the industry around a common term and reducing confusion in the industry over misleading terminologies. ARS is committed to supporting both ESA and NASA in updating publications and practices on Direct Field Acoustic Testing, and we are ready to continue serving the industry while working toward a unified position that benefits everyone.

Conclusion

Unfortunately, as of this publication, the term “DFAT” is still trademarked. Despite it being utilized in publicly released standards, we hear our industry colleagues and partners continuing to voice their frustration over the confusion this causes. While there was an opportunity to help move the industry forward in unity under a single acronym, the restricted usage of the acronym “DFAT” was renewed as recently as October 2022.

So, if you’re searching for more information about Direct Field Acoustic Testing, the publicly available acronym that the industry is coalescing around is DFAN. For end users writing specifications, it best describes the process of performing Direct Field Acoustic Testing and avoids any potential legal issues regarding trademark infringement. Searching for DFAN also is the best way to find a wide range of publicly available information and many valuable viewpoints on Direct Field Acoustic Testing.

This is a topic that we will continue to discuss as we work to learn and shed new light on the history of Direct Field Acoustic Testing, as well as the future of Direct Field Acoustic Testing. We believe that simplification and unification is the best approach for the industry to take. With this in mind, we will continue our efforts to lead the conversation on behalf of our partners and the industry at large, and advocate for unity and clarity in the marketplace.