Reimagining Dialogue Clarity: How NUGEN’s DialogCheck With Fraunhofer’s Listening Effort Meter Changes the Game for Audio Professionals

By: Charles Blessing, Chief Technology Officer, NUGEN Audio

In today’s media landscape, audio clarity isn’t a luxury — it’s an expectation. Yet, for many productions, ensuring that dialogue remains intelligible across a broad range of listening environments is still a persistent challenge. Whether it’s due to the increasing complexity of mixes, viewer distraction or the wide variability of playback systems, clear dialogue is often the first casualty in the battle between artistic intention and real-world reception.

Recognizing this, NUGEN Audio has introduced DialogCheck, a groundbreaking plug-in designed to objectively measure and evaluate dialogue intelligibility in audio production. At the core of this innovation is a remarkable collaboration with Fraunhofer Institute for Digital Media Technology (IDMT) — specifically, its Oldenburg Branch for Hearing, Speech and Audio Technology (HSA), which developed the scientific backbone of the solution: the Listening Effort Meter (LE-Meter).

This partnership is more than just a technological integration. It’s a union between applied research and professional audio craftsmanship, designed to bring measurable clarity to a problem that has long relied on subjective interpretation.

Understanding Dialogue Intelligibility and Why It’s Hard to Get Right

Poor speech intelligibility has become one of the most frequent complaints from television and film audiences. According to a 2022 EBU Tech Review, intelligibility issues remain a leading cause of viewer dissatisfaction. For audio engineers, however, determining how “clear” dialogue is can be deceptively difficult. Human familiarity with the material, controlled mixing environments and even subconscious lip-reading can distort an engineer’s ability to judge clarity in a way that reflects the average listener’s experience.

That’s where NUGEN Audio’s DialogCheck comes in. It doesn’t process or alter the audio; it simply measures it. The plug-in provides engineers with a real-time and historical view of dialogue clarity across an entire mix. With tools like bar meters, history graphs, statistical distribution views and exportable data, DialogCheck assists professionals with assessing where dialogue might get lost and why.

The heart of its accuracy lies in its algorithmic engine, powered by Fraunhofer’s LE-Meter.

The Science Behind the Sound: Introducing the Listening Effort Meter

The LE-Meter is a software tool designed to assess dialogue intelligibility using automatic speech recognition (ASR) and psychoacoustic modeling. Unlike conventional volume or loudness meters, which provide only indirect indications of clarity, the LE-Meter focuses on how hard a listener must work to understand speech in context.

This approach reflects a more realistic model of human perception. It doesn’t just measure how loud the dialogue is — it analyzes how much mental energy a listener must expend to comprehend it, especially in challenging conditions such as competing music, background effects or dynamic EQ adjustments.

The LE-Meter has undergone rigorous validation through systematic listening tests, showing a high correlation with subjective listener feedback. That correlation is the key to avoiding personal biases. Engineers can now rely on objective metrics that reflect real-world perception instead of second-guessing their mixes based on listening environment or other external factors.

From Research Lab to Production Suite

What makes the integration of the LE-Meter into DialogCheck truly revolutionary is its implementation as a DAW plug-in. Thanks to NUGEN’s interface design, the advanced technology developed at Fraunhofer IDMT is now accessible to any post-production engineer or sound designer, no matter the size of their team or budget.

Engineers using DialogCheck can now visualize listening effort in real-time and over the course of an entire mix; compare statistical metrics such as average, minimum, maximum and percentile values for dialogue clarity; identify problem areas in a timeline-based view, backed by psychoacoustic science; and export detailed reports to support quality control, editorial review or compliance documentation.

The tool becomes especially valuable in fast-paced workflows where multiple mixes are being reviewed in tight timelines, or when content needs to meet specific broadcast or streaming intelligibility standards. DialogCheck takes the guesswork out of mix evaluation and replaces it with data-informed precision.

Applications Across the Audio Spectrum

While DialogCheck is primarily designed for post-production environments (film, television, streaming, radio, podcasting and game audio), it also has significant value in pre-production and live broadcast settings.

During pre-production, engineers can use the plug-in to evaluate microphone placement, room acoustics and performance style, helping ensure strong dialogue capture at the source. In live or live-to-tape environments, DialogCheck can serve as a last-line verification step before a final render or master delivery, confirming that dialogue meets clarity thresholds even in less-than-ideal mixes.

Additionally, because DialogCheck offers objective insight, the tool can be instrumental for accessibility workflows, ensuring that spoken content remains comprehensible to audiences with hearing challenges or in situations with poor listening conditions (e.g., mobile devices, noisy environments).

Bridging the Gap Between Technology and Creativity

One of the persistent tensions in audio post is the balance between creative mix choices and technical clarity. Sound designers often make intentional decisions to bury or obscure dialogue for dramatic effect, but those choices need to be grounded in an understanding of how the final audience will experience the content.

DialogCheck doesn’t constrain creativity; it informs it. By providing quantifiable feedback on dialogue intelligibility, engineers are empowered to make clearer decisions. They can choose to push dialogue back in the mix for artistic reasons, but they’ll do so knowing precisely how that choice impacts listener comprehension.

A Future of Better Listening

By incorporating Fraunhofer IDMT’s research-grade metrics into a production-ready tool, NUGEN Audio has delivered a plug-in that meets a critical industry need. As audiences consume an increasing amount of content across a variety of platforms, and often in unpredictable environments, the pressure on post-production teams to deliver high-quality, intelligible dialogue has never been greater.

With DialogCheck, engineers now have the tools to meet that challenge head-on, leveraging world-class psychoacoustic modeling to ensure that the most important element in a mix is always heard.

Charles Blessing is a Software Engineer and Chief Technology Officer (CTO) of NUGEN Audio. He joined NUGEN in 2013 and focuses on building reliable products and solutions. Outside of NUGEN he can often be found tinkering on his latest project in his garage/workshop.