diff --git a/tortoise/api.py b/tortoise/api.py
index bc2eff8..07f4878 100755
--- a/tortoise/api.py
+++ b/tortoise/api.py
@@ -228,7 +228,7 @@ class TextToSpeech:
         """
         self.minor_optimizations = minor_optimizations
         self.models_dir = models_dir
-        self.autoregressive_batch_size = pick_best_batch_size_for_gpu() if autoregressive_batch_size is None else autoregressive_batch_size
+        self.autoregressive_batch_size = pick_best_batch_size_for_gpu() if autoregressive_batch_size is None or autoregressive_batch_size == 0 else autoregressive_batch_size
         self.enable_redaction = enable_redaction
         self.device = torch.device('cuda' if torch.cuda.is_available() else 'cpu')
         if self.enable_redaction:
@@ -465,7 +465,7 @@ class TextToSpeech:
 
         diffuser = load_discrete_vocoder_diffuser(desired_diffusion_steps=diffusion_iterations, cond_free=cond_free, cond_free_k=cond_free_k)
 
-        self.autoregressive_batch_size = pick_best_batch_size_for_gpu() if sample_batch_size is None else sample_batch_size
+        self.autoregressive_batch_size = pick_best_batch_size_for_gpu() if sample_batch_size is None or sample_batch_size == 0 else sample_batch_size
 
         with torch.no_grad():
             samples = []