Google’s NotebookLM just gave its AI research tool a big audio upgrade.
Starting this week, users can hear their sources explained not just through the default Deep Dive, but also via a fast Brief, an expert-style Critique, or even a two-voice Debate.
Key Takeaways
- NotebookLM rolls out three new audio overview formats worldwide.
- Options include Brief, Critique, and Debate alongside the Deep Dive.
- Critique offers expert-style feedback on strengths and weaknesses.
- Debate creates a back-and-forth dialogue between two AI hosts.
- Update signals Google’s bigger push into study and creative AI tools.
NotebookLM has introduced three new audio overview formats — Brief, Critique, and Debate — to complement its default Deep Dive. Users can now get short summaries, expert-style reviews, or back-and-forth discussions of their source material, making the AI research tool more versatile for learning, studying, and creative exploration.
Google’s AI Notebook Expands Its Audio Toolkit
NotebookLM, Google’s AI-powered research companion, is adding more ways for users to interact with information. On Tuesday, the company announced three new audio overview formats — Brief, Critique, and Debate — expanding beyond the existing Deep Dive.
The update reflects Google’s effort to make NotebookLM feel more like a flexible study partner rather than a rigid research tool.
Breaking Down the New Audio Modes
The four audio options now available include:
- Deep Dive — A structured, comprehensive walkthrough of your material. Best for developing a full understanding.
- Brief — A 1–2 minute summary that works as an “executive snapshot.”
- Critique — An evaluative review that highlights strengths, weaknesses, and areas for improvement.
- Debate — A conversational back-and-forth between two AI “hosts” with different perspectives.
NotebookLM showcased the new lineup on X this week, noting that the formats are already visible behind a feature flag in production.
🚨Rolling out NEW audio overview formats:
— NotebookLM (@NotebookLM) September 2, 2025
(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
Why These New Modes Could Change How You Study
The change isn’t just about variety — it’s about depth and flexibility. For students, the Brief mode can serve as a quick refresher before exams. For researchers, the Critique mode mimics peer review, pointing out gaps and overlooked angles. And for creators, Debate provides a way to stress-test ideas by surfacing opposing arguments.
NotebookLM’s positioning is clear: Google wants it to be the “thinking partner” that can switch modes depending on the task.
User Reactions: Critique Gets the Spotlight
Among the three new options, Critique is drawing the most attention from early testers. Many see it as a step toward overcoming the “yes-man” problem in AI tools, where systems only affirm user input without pushing back.
Still, not every format is perfect. Debate mode, while engaging, risks becoming lengthy and less practical for time-pressed users. That’s where Brief helps — offering a counterbalance with bite-sized insights.
NotebookLM also highlighted multilingual improvements last week, including support for 80 languages and longer non-English audio overviews.
Google’s Broader Play for AI in Learning
NotebookLM began as a side project but has steadily evolved into a showcase for Google’s applied AI. Audio features, in particular, are central to its push into education and creativity.
By offering formats that mimic podcasts, peer reviews, and executive briefings, NotebookLM is moving closer to being a tool not just for research but for content creation and ideation.
When You’ll Actually See the Update Roll Out
The new formats are rolling out gradually, hidden behind a feature flag but already accessible in production. That suggests a broader public release is imminent.
For now, NotebookLM’s experiment is clear: can AI not only explain information but also challenge, summarize, and debate it? If so, the tool could reshape how people prepare for exams, pitch ideas, or critique their own work.
Conclusion
NotebookLM’s new Brief, Critique, and Debate audio modes expand its role from explainer to collaborator. Whether you’re looking for fast insights, constructive criticism, or a simulated argument, Google’s AI is aiming to meet you where you are.