diff --git a/egs/fisher_swbd/ASR/local/compute_fbank_musan.py b/egs/fisher_swbd/ASR/local/compute_fbank_musan.py
index f97002b82..acb477540 100755
--- a/egs/fisher_swbd/ASR/local/compute_fbank_musan.py
+++ b/egs/fisher_swbd/ASR/local/compute_fbank_musan.py
@@ -28,7 +28,7 @@ import os
 from pathlib import Path
 
 import torch
-from lhotse import CutSet, Fbank, FbankConfig, combine
+from lhotse import CutSet, Fbank, FbankConfig, LilcomChunkyWriter, combine
 from lhotse.recipes.utils import read_manifests_if_cached
 
 from icefall.utils import get_executor
@@ -52,12 +52,22 @@ def compute_fbank_musan():
         "speech",
         "noise",
     )
+    prefix = "musan"
+    suffix = "jsonl.gz"
     manifests = read_manifests_if_cached(
-        dataset_parts=dataset_parts, output_dir=src_dir, lazy=True, suffix="jsonl"
+        dataset_parts=dataset_parts,
+        output_dir=src_dir,
+        prefix=prefix,
+        suffix=suffix,
     )
     assert manifests is not None
 
-    musan_cuts_path = output_dir / "cuts_musan.json.gz"
+    assert len(manifests) == len(dataset_parts), (
+        len(manifests),
+        len(dataset_parts),
+    )
+
+    musan_cuts_path = output_dir / "musan_cuts.jsonl.gz"
 
     if musan_cuts_path.is_file():
         logging.info(f"{musan_cuts_path} already exists - skipping")
@@ -65,7 +75,7 @@ def compute_fbank_musan():
 
     logging.info("Extracting features for Musan")
 
-    extractor = Fbank(FbankConfig(num_mel_bins=num_mel_bins, sampling_rate=sampling_rate))
+    extractor = Fbank(FbankConfig(num_mel_bins=num_mel_bins, sampling_rate=sampling_rate)
 
     with get_executor() as ex:  # Initialize the executor only once.
         # create chunks of Musan with duration 5 - 10 seconds
@@ -79,12 +89,13 @@ def compute_fbank_musan():
             .filter(lambda c: c.duration > 5)
             .compute_and_store_features(
                 extractor=extractor,
-                storage_path=f"{output_dir}/feats_musan",
+                storage_path=f"{output_dir}/musan_feats",
                 num_jobs=num_jobs if ex is None else 80,
                 executor=ex,
+                storage_type=LilcomChunkyWriter,
             )
         )
-        musan_cuts.to_json(musan_cuts_path)
+        musan_cuts.to_file(musan_cuts_path)
 
 
 if __name__ == "__main__":
diff --git a/egs/fisher_swbd/ASR/prepare.sh b/egs/fisher_swbd/ASR/prepare.sh
index 7cb587f3d..787e555fc 100755
--- a/egs/fisher_swbd/ASR/prepare.sh
+++ b/egs/fisher_swbd/ASR/prepare.sh
@@ -183,12 +183,7 @@ if [ $stage -le 6 ] && [ $stop_stage -ge 6 ]; then
   # We assume that you have downloaded the musan corpus                                                                                      
   # to data/musan                                                                                                                            
   mkdir -p data/manifests/musan
-  lhotse prepare musan $dl_dir/musan data/manifests/musan
-  
-  for name in music noise speech ; do
-      jq -c '.[]' data/manifests/musan/recordings_${name}.json > data/manifests/recordings_${name}.jsonl
-      gzip -c data/manifests/recordings_${name}.jsonl > data/manifests/recordings_${name}.jsonl.gz
-  done
+  lhotse prepare musan $dl_dir/musan data/manifests/musan  
 fi
 
 if [ $stage -le 7 ] && [ $stop_stage -ge 7 ]; then