Audio ML PapersLandmark papers
← All papers
RESEARCH PAPER / 2025-09-20

An Octave-based Multi-Resolution CQT Architecture for Diffusion-based Audio Generation

Maurício do V. M. da Costa, Eloi Moliner

Both authors contributed equally to this work. It was funded by Volkswagen Foundation (Volkswagen Stiftung) Germany +1 · accepted at IEEE International Symposium on the Internet of Sounds

Affiliations: Both authors contributed equally to this work. It was funded by Volkswagen Foundation (Volkswagen Stiftung) Germany, under Grant no. 96 881

Abstract

This paper introduces MR-CQTdiff, a novel neural-network architecture for diffusion-based audio generation that leverages a multi-resolution Constant-$Q$ Transform (C$Q$T). The proposed architecture employs an efficient, invertible CQT framework that adjusts the time-frequency resolution on an octave-by-octave basis. This design addresses the issue of low temporal resolution at lower frequencies, enabling more flexible and expressive audio generation. We conduct an evaluation using the Fr\'echet Audio Distance (FAD) metric across various architectures and two datasets. Experimental results demonstrate that MR-CQTdiff achieves state-of-the-art audio quality, outperforming competing architectures.

The following analysis is generated by AI and may contain errors. It is separate from the authors’ abstract and is not peer review.

Research summary

The paper introduces MR-CQTdiff, a novel architecture for diffusion-based audio generation that leverages a multi-resolution constant-Q transform to improve audio quality. The comprehensive analysis highlights its innovative methodology, robust experimental validation, and significant implications for the field of audio processing and generation.

Methodology

The paper presents a well-structured methodology that introduces the MR-CQTdiff architecture, which innovatively employs a multi-resolution Constant-Q Transform (CQT) to enhance diffusion-based audio generation. The architecture's design addresses the critical trade-off between time and frequency resolution, particularly for low-frequency audio signals, by utilizing multiple parallel CQT filters. This approach allows for better capture of transient audio events and harmonically rich content, which is a significant improvement over existing methods. The use of a U-Net structure facilitates effective feature reuse and gradient flow, enhancing the model's training stability.

Results & evaluation

The experimental evaluation is robust, utilizing two diverse datasets (FMA-Large and OpenSinger) to assess the performance of MR-CQTdiff against several strong baselines. The use of the Fréchet Audio Distance (FAD) metric provides a quantitative measure of audio quality, and the results demonstrate that MR-CQTdiff consistently outperforms other models, particularly in capturing transient details in vocal audio. The thoroughness of the experiments, including the comparison with latent diffusion models, adds credibility to the findings.

Reproducibility

The paper provides sufficient implementation details, including the architecture specifications, training parameters, and dataset descriptions, which enhance reproducibility. The availability of the code on GitHub and the demo page with audio samples further supports this aspect, allowing other researchers to replicate the experiments and validate the results.

Limitations

While the proposed architecture shows promising results, the paper acknowledges limitations in terms of computational efficiency compared to latent diffusion models. The focus on audio generation quality may lead to increased resource consumption, which could be a barrier for broader applications. Additionally, the evaluation primarily focuses on unconditional generation, and further exploration of conditional generation tasks could provide deeper insights into the model's capabilities.

Broader impact

The MR-CQTdiff architecture has significant potential applications in various audio generation tasks, including music synthesis, sound design, and audio restoration. By improving the quality of generated audio, this work could influence the development of more sophisticated audio generation tools and enhance user experiences in creative industries. The findings may also inspire further research into time-frequency representations in generative models, potentially leading to advancements in other domains of machine learning. The paper introduces MR-CQTdiff, a novel architecture for diffusion-based audio generation that leverages a multi-resolution constant-Q transform to improve audio quality. The comprehensive analysis highlights its innovative methodology, robust experimental validation, and significant implications for the field of audio processing and generation.

Author of this paper? Send a correction.