标题： 基于帧的频谱处理的相位器效果的可微灰盒建模 显示英文标题

标题： Differentiable Grey-box Modelling of Phaser Effects using Frame-based Spectral Processing

摘要： 近年来，机器学习方法在建模模拟音频效果方面得到了深入研究，特别是在非线性时不变效果（如吉他放大器）的背景下。然而，对于如相位器之类的调制效果，由于存在控制缓慢时间变化效果的低频振荡器，会出现新的挑战。现有的方法要么需要预先知道该控制信号，要么在实现上是非因果的。本工作提出了一种可微分的数字信号处理方法来建模相位器效果，其中底层控制信号和时间变化的频谱响应是联合学习的。所提出的模型通过在频域中处理音频的短帧来实现时间变化的滤波器，其传递函数基于典型的模拟相位器电路拓扑结构。我们展示了该模型可以被训练以模仿模拟参考设备，同时保留可解释和可调整的参数。帧长度是所提模型的重要超参数，因此对其对模型准确性的影响进行了研究。最佳帧长度取决于目标效果的速率和瞬态衰减时间，但在推理时可以改变帧长度而不会显著影响准确性。 显示英文摘要

摘要： Machine learning approaches to modelling analog audio effects have seen intensive investigation in recent years, particularly in the context of non-linear time-invariant effects such as guitar amplifiers. For modulation effects such as phasers, however, new challenges emerge due to the presence of the low-frequency oscillator which controls the slowly time-varying nature of the effect. Existing approaches have either required foreknowledge of this control signal, or have been non-causal in implementation. This work presents a differentiable digital signal processing approach to modelling phaser effects in which the underlying control signal and time-varying spectral response of the effect are jointly learned. The proposed model processes audio in short frames to implement a time-varying filter in the frequency domain, with a transfer function based on typical analog phaser circuit topology. We show that the model can be trained to emulate an analog reference device, while retaining interpretable and adjustable parameters. The frame duration is an important hyper-parameter of the proposed model, so an investigation was carried out into its effect on model accuracy. The optimal frame length depends on both the rate and transient decay-time of the target effect, but the frame length can be altered at inference time without a significant change in accuracy.