diff --git a/src/spikeinterface/preprocessing/silence_periods.py b/src/spikeinterface/preprocessing/silence_periods.py
index 4299d199ed..9cfefa9618 100644
--- a/src/spikeinterface/preprocessing/silence_periods.py
+++ b/src/spikeinterface/preprocessing/silence_periods.py
@@ -20,6 +20,8 @@ class SilencedPeriodsRecording(BasePreprocessor):
         The recording extractor to silance periods
     list_periods: list of lists/arrays
         One list per segment of tuples (start_frame, end_frame) to silence
+    noise_levels: array
+        Noise levels if already computed
 
     mode: "zeros" | "noise, default: "zeros"
         Determines what periods are replaced by. Can be one of the following:
@@ -39,9 +41,7 @@ class SilencedPeriodsRecording(BasePreprocessor):
 
     name = "silence_periods"
 
-    def __init__(self, recording, list_periods, mode="zeros", **random_chunk_kwargs):
-        import scipy.interpolate
-
+    def __init__(self, recording, list_periods, mode="zeros", noise_levels=None, **random_chunk_kwargs):
         available_modes = ("zeros", "noise")
         num_seg = recording.get_num_segments()
 
@@ -67,7 +67,10 @@ def __init__(self, recording, list_periods, mode="zeros", **random_chunk_kwargs)
                 ), "Intervals should not overlap"
 
         if mode in ["noise"]:
-            noise_levels = get_noise_levels(recording, return_scaled=False, concatenated=True, **random_chunk_kwargs)
+            if noise_levels is None:
+                noise_levels = get_noise_levels(
+                    recording, return_scaled=False, concatenated=True, **random_chunk_kwargs
+                )
         else:
             noise_levels = None
 
@@ -79,9 +82,7 @@ def __init__(self, recording, list_periods, mode="zeros", **random_chunk_kwargs)
             rec_segment = SilencedPeriodsRecordingSegment(parent_segment, periods, mode, noise_levels)
             self.add_recording_segment(rec_segment)
 
-        self._kwargs = dict(
-            recording=recording.to_dict(), list_periods=list_periods, mode=mode, noise_levels=noise_levels
-        )
+        self._kwargs = dict(recording=recording, list_periods=list_periods, mode=mode, noise_levels=noise_levels)
 
 
 class SilencedPeriodsRecordingSegment(BasePreprocessorSegment):