San Francisco-based voice artificial intelligence startup Rime has secured $24 million in a Series A funding round led by M13 Ventures, with participation from Twilio Ventures, Corazon Capital, and Unusual Ventures. The capital will support the company expansion into enterprise customer service, sales, and marketing automation, aiming to overcome persistent friction in AI voice adoption. Founded in 2022 by former Stanford researcher Lily Clifford, ex Amazon Alexa engineer Brooke Larson, and Stanford engineer Ares Geovanos, Rime differentiates its platform by prioritizing proprietary data collection over public web scraping. The company operates a dedicated San Francisco recording studio to capture high quality conversational audio, which it uses to train phoneme based models that accurately handle industry specific terminology and brand entity pronunciation without requiring extensive client side retraining. Rime is simultaneously engineering a fundamental shift in its technical architecture, moving away from fragmented speech to text, text to speech, and large language model pipelines toward unified speech to speech models. This transition is designed to minimize latency, improve natural conversational turn taking, and mitigate background noise interference, while reducing the operational overhead of managing multiple orchestration layers. M13 Ventures partner Morgan Blumberg noted that the company focus on low latency, high reliability voice models built for regulated enterprise environments positions it effectively against both infrastructure providers and application layer competitors. Despite these technical advancements, founder Lily Clifford acknowledged that enterprise voice AI still lags behind traditional interactive voice response systems in overall effectiveness and user satisfaction. She characterized current AI voice interactions as functionally similar to legacy IVR menus but with improved audio fidelity, emphasizing that substantial experiential gaps remain before widespread automation can take hold. To bridge this divide, Rime concentrates on optimizing call duration and interaction quality, a strategy that has already secured enterprise contracts across healthcare, aviation, fintech, and food service sectors. Notable clients include Mayo Clinic, Dialpad, Upstart, and Asurion. Following the financing, Rime will scale its workforce of thirty five employees, prioritizing recruitment in model development, software engineering, and strategic partnerships. The startup recently appointed Rafael Valle, formerly of Meta Superintelligence Labs and NVIDIA audio research teams, as its Chief Scientist. Blumberg will join the company board of directors as part of the investment terms. The round builds upon a $5.5 million seed funding secured last May, providing Rime with the resources to refine its speech to speech infrastructure and accelerate integration within large scale enterprise communication workflows.