use torchaudio instead of soundfile in separate speaker core

gradio_app.py

@@ -52,12 +52,14 @@ def separate_speakers_core(audio_path):
     output_files = []
     for i in range(ests_speech.shape[0]):
         path = os.path.join(output_dir, f"speaker_{i+1}.wav")
-        sf.write(path, ests_speech[i].cpu().numpy(), TARGET_SR)
+        waveform = ests_speech[i].unsqueeze(0).cpu()  # shape: (1, samples)
+        torchaudio.save(path, waveform, TARGET_SR)    # Saves as valid WAV
         output_files.append(path)
 
     return output_files
 
 
+
 @spaces.GPU()
 def separate_dnr(audio_file):
     audio, sr = torchaudio.load(audio_file)