NotebookLM, a Gemini-powered AI research assistant, will soon generate a debate or critique your research and notes in its Audio Overviews feature. Three new audio summary formats announced on Tuesday — called Brief, Critique and Debate — will give users more options and add more flavor to what is already one of Google’s best AI tools.
The Audio Overviews feature was a catalyst for NotebookLM’s popularity as a note-taking tool that uses only the sources you provide and makes the information more digestible. NotebookLM is multimodal, so you can create a podcast-like Audio Overview or generate a study guide if that’s more your style.
Though Audio Overviews was novel when first demoed in 2024, Google has since incorporated it into more of its products. Google recently introduced the first Video Overview format, too. Here’s what’s new.
🚨Rolling out NEW audio overview formats:
(Default) Deep Dive: a thorough examination of your sources
Brief: 1-2 minute, bite-sized overviews
Critique: an expert review, offering constructive feedback on your material
Debate: a thoughtful debate between two hosts pic.twitter.com/m3z3yASMyF— NotebookLM (@NotebookLM) September 2, 2025
New Audio Overviews: Brief, Critique, Debate
When first introduced, Audio Overviews provided a “deep dive” on your sources, cutting through the fat and focusing on a general overview of the subject.
Later, Google introduced a way to customize your Audio Overviews so you can focus on the material that matters most to you. You can also customize the length of an overview.
While the default option is still the typical Deep Dive, three new options — Brief, Critique and Debate — are rolling out to users now.
- Brief: 1-2 minute bite-size overview
- Critique: Constructive feedback on materials
- Debate: Two hosts engaging in a thoughtful debate
Though I haven’t been able to test out the new Overview types, I imagine both the Critique and Debate formats could be useful for learning different perspectives that you may not have previously considered.
The introduction of different Audio Overview formats is a solid upgrade, especially if you’re looking for alternative approaches to a subject. The new formats also open the doors for even more options in the future, allowing NotebookLM to become a more nuanced learning tool.
