diff --git a/egs/librispeech/ASR/pruned_transducer_stateless7/optim.py b/egs/librispeech/ASR/pruned_transducer_stateless7/optim.py
index bf41f48bd..02a2c58a8 100644
--- a/egs/librispeech/ASR/pruned_transducer_stateless7/optim.py
+++ b/egs/librispeech/ASR/pruned_transducer_stateless7/optim.py
@@ -164,7 +164,7 @@ param_rms_smooth1: Smoothing proportion for parameter matrix, if assumed rank of
             betas=(0.9, 0.98),
             size_lr_scale=0.1,
             cov_min=(0.025, 0.0025, 0.1, 0.0001),
-            cov_max=(5.0, 20.0, 4.0, 40.0),
+            cov_max=(5.0, 20.0, 3.5, 40.0),
             cov_pow=(1.0, 1.0, 1.0, 1.0),
             param_rms_smooth0=0.4,
             param_rms_smooth1=0.2,