Soundwave: Less is More for Speech-Text Alignment in LLMs
Yuhao Zhang, Zhiheng Liu, Fan Bu, Ruiyu Zhang, Benyou Wang, Haizhou Li
TL;DR
Soundwave tackles data inefficiency in speech–text LLM alignment by separating the problem into representation alignment and sequence-length reduction, implemented via a three-stage training framework. It introduces two adapters (alignment and shrinking) and leverages a frozen Whisper encoder with LoRA to bridge speech and text efficiently, achieving state-of-the-art AIR-Bench performance with roughly 10k hours of data (and competitive zero-shot translation) while using far less data than prior systems. The method combines auxiliary CTC loss, high-quality alignment data, dynamic data mixing, and instruction-focused fine-tuning to maintain conversational capabilities and knowledge-based QA. This approach significantly lowers training costs and data requirements for speech-capable LLMs, enabling broader accessibility and faster iteration, albeit with some limitations in ASR competitiveness and multilingual coverage that point to future scaling and data expansion.
Abstract
Existing end-to-end speech large language models (LLMs) usually rely on large-scale annotated data for training, while data-efficient training has not been discussed in depth. We focus on two fundamental problems between speech and text: the representation space gap and sequence length inconsistency. We propose Soundwave, which utilizes an efficient training strategy and a novel architecture to address these issues. Results show that Soundwave outperforms the advanced Qwen2-Audio in speech translation and AIR-Bench speech tasks, using only one-fiftieth of the training data. Further analysis shows that Soundwave still retains its intelligence during conversation. The project is available at https://github.com/FreedomIntelligence/Soundwave.
