RuntimeError: mat1 and mat2 shapes cannot be multiplied (80x513 and 1x513)

**Summary[问题简述（一句话）]**
spec = torch.matmul(mel_basis[str(fmax)+'_'+str(y.device)], spec)
RuntimeError: mat1 and mat2 shapes cannot be multiplied (80x513 and 1x513)

**Env & To Reproduce[复现与环境]**
win11 torch: 2.3.0+cu118 python38

**Screenshots[截图（如有）]**

Start by locating the code containing `spec = torch.matmul(mel_basis[str(fmax)+'_'+str(y.device)], spec)` and reproduce the reported failure with Windows 11, Python 3.8, and torch 2.3.0+cu118. Inspect the shapes of `mel_basis` and `spec` at that point and determine what behavior the multiplication should have; done means the reproduction no longer raises the reported shape-mismatch error.

Written by the indexing model from the issue text.