Cartesia has announced a $27 million seed funding round led by Index Ventures, with contributions from multiple other investors, to advance its mission of creating real-time intelligence with long memory. The company aims to overcome the limitations of current Transformer models, which struggle with processing long sequences and real-time efficiency, by developing new architectures like S4 and Mamba that scale linearly with sequence length and improve data compression. Cartesia's innovations include Sonic, a fast, hyper-realistic voice generation model now used by thousands of customers, and a new multi-stream architecture for simultaneous reasoning across different data modalities. This architecture allows for fine-grained control and prevents issues like hallucinations in voice generation, crucial for applications requiring high accuracy. The company plans to expand its real-time, multimodal AI capabilities and encourages interested individuals to join their efforts.