What if AI could talk back instantly—and naturally?In this episode, Karan Goel, Co-founder & CEO of Cartesia, joins Barr Yaron to unpack the future of voice AI, state space models (SSMs), and why audio is the next frontier in AI.

Karan shares the founding story behind Cartesia, explains how alternate architectures like Mamba enable ultra-efficient, low-latency inference, and walks through how his team is building the fastest text-to-speech model in the world—while obsessing over every millisecond.

Whether you’re into model architectures, AI infrastructure, or the future of voice interfaces, this episode delivers technical depth, startup lessons, and a roadmap for what’s coming next.This episode is broken down into the following chapters:

00:00 – Intro

01:06 – Karan’s journey from CMU PhD to startup founder

03:56 – Why Cartesia is built around state space models

06:49 – What makes SSMs different from transformers

09:14 – Why compression matters for long-running AI systems

11:13 – What data types SSMs are best (and worst) for

13:39 – Scaling SSMs: What’s possible and what’s missing

15:31 – Hardware, GPUs & why SSMs work well on existing infra

18:46 – Landing on audio: Cartesia’s first core modality

22:38 – Navigating the model vs. market debate in AI startups

26:36 – How Cartesia built Sonic, their ultra-low latency TTS model

28:17 – Why latency is the #1 challenge in voice AI

30:46 – Tricks vs. model-first thinking: Baking it into the model

34:01 – How Cartesia balances fast execution with deep research

36:26 – Building with part-time academic co-founders

38:13 – Yes, every employee gets a personal Yoshi

40:02 – Where voice AI is being adopted first (telephony + beyond)

42:24 – Multilingual modeling & the long tail of language

45:02 – Voice as a new computing interface

46:26 – Why voice notes are the future (and Barr’s hot take)

49:56 – How Cartesia evaluates its models

52:44 – How Karan has grown as a founder and leader

Subscribe to the Barrchives newsletter: https://www.barrchives.com/

Spotify: https://open.spotify.com/show/37O8Pb0LgqpqTXo2GZiPXf

Apple: https://podcasts.apple.com/us/podcast/barrchives/id1774292613

Twitter: https://x.com/barrnanas

LinkedIn: https://www.linkedin.com/in/barryaron/