diff --git a/src/lasp/lasp_slm.py b/src/lasp/lasp_slm.py
index f00af31..6dbc135 100644
--- a/src/lasp/lasp_slm.py
+++ b/src/lasp/lasp_slm.py
@@ -27,35 +27,35 @@ class SLM:
     Multi-channel Sound Level Meter. Input data: time data with a certain
     sampling frequency. Output: time-weighted (fast/slow) sound pressure
     levels in dB(A/C/Z). Possibly in octave bands.
-
     """
 
     def __init__(self,
                  fs,
-                 fbdesigner=None, 
+                 fbdesigner=None,
                  tw: TimeWeighting =TimeWeighting.fast,
                  fw: FreqWeighting =FreqWeighting.A,
                  xmin = None,
                  xmax = None,
                  include_overall=True,
-                 level_ref_value=P_REF):
+                 level_ref_value=P_REF,
+                 offset_t=0):
         """
         Initialize a sound level meter object.
 
         Args:
             fs: Sampling frequency of input data [Hz]
-            fbdesigner: FilterBankDesigner to use for creating the 
+            fbdesigner: FilterBankDesigner to use for creating the
             (fractional) octave bank filters. Set this one to None to only do
             overalls
             fs: Sampling frequency [Hz]
             tw: Time Weighting to apply
             fw: Frequency weighting to apply
-            xmin: Filter designator of lowest band. 
+            xmin: Filter designator of lowest band.
             xmax: Filter designator of highest band
             include_overall: If true, a non-functioning filter is added which
             is used to compute the overall level.
             level_ref_value: Reference value for computing the levels in dB
-
+            offset_t: Offset to be added to output time data [s]
             """
 
         self.fbdesigner = fbdesigner
@@ -63,8 +63,8 @@ class SLM:
             xmin = fbdesigner.xs[0]
         elif fbdesigner is None:
             xmin = 0
-            
-        if xmax is None and self.fbdesigner is not None: 
+
+        if xmax is None and self.fbdesigner is not None:
             xmax = fbdesigner.xs[-1]
         elif fbdesigner is None:
             xmax = 0
@@ -74,7 +74,8 @@ class SLM:
         nfilters = len(self.xs)
         if include_overall: nfilters +=1
         self.include_overall = include_overall
-        
+        self.offset_t = offset_t
+
         spld = SPLFilterDesigner(fs)
         if fw == FreqWeighting.A:
             prefilter = spld.A_Sos_design().flatten()
@@ -104,7 +105,7 @@ class SLM:
                 self.nom_txt.append(fbdesigner.nominal_txt(x))
 
             if include_overall:
-                # Create a unit impulse response filter, every third index equals 
+                # Create a unit impulse response filter, every third index equals
                 # 1, so b0 = 1 and a0 is 1 (by definition)
                 # a0 = 1, b0 = 1, rest is zero
                 sos[:,-1] = sos_overall
@@ -119,7 +120,7 @@ class SLM:
 
         # Downsampling factor, determine from single pole low pass filter time
         # constant, such that aliasing is ~ allowed at 20 dB lower value
-        # and 
+        # and
         dsfac = cppSLM.suggestedDownSamplingFac(fs, tw[0])
 
         if prefilter is not None:
@@ -153,14 +154,14 @@ class SLM:
         Ncur = levels.shape[0]
         tend = tstart + Ncur / self.fs_slm
 
-        t = np.linspace(tstart, tend, Ncur, endpoint=False)
+        t = np.linspace(tstart, tend, Ncur, endpoint=False) + self.offset_t
         self.N += Ncur
 
         output = {}
 
         for i, x in enumerate(self.xs):
             # '31.5' to '16k'
-            output[self.nom_txt[i]] = {'t': t, 
+            output[self.nom_txt[i]] = {'t': t,
                                        'data': levels[:, [i]],
                                        'x': x}
         if self.include_overall and self.fbdesigner is not None: