diff --git a/ringdown/data.py b/ringdown/data.py
index 6841ed9d..c7184c1d 100644
--- a/ringdown/data.py
+++ b/ringdown/data.py
@@ -234,7 +234,7 @@ def load(cls, path: str | None = None, channel: str | None = None, **kws):
         ts.attrs.update(dict(load=info))
         return ts
 
-    _DEF_INTERP_KWS = dict(kind='cubic', fill_value=0, bounds_error=False)
+    _DEF_INTERP_KWS = dict(kind='linear', fill_value=0, bounds_error=False)
 
     def interpolate_to_index(self, new_index, **kwargs):
         """Reinterpolate the :class:`Series` to new index.
@@ -462,7 +462,8 @@ def interpolate_to_index(self, freq: np.ndarray | None = None,
             f_min = f_min_orig if f_min is None else f_min
             f_max = f_max_orig if f_max is None else f_max
             delta_f = delta_f or self.delta_f
-            n = int((f_max - f_min) / delta_f) + 1
+            # n = int((f_max - f_min) / delta_f) + 1
+            n = len(self.freq)
             freq = np.arange(n)*delta_f + f_min
 
         if min(freq) < f_min_orig or max(freq) > f_max_orig:
diff --git a/ringdown/fit.py b/ringdown/fit.py
index 17e7ee91..3a067fb7 100644
--- a/ringdown/fit.py
+++ b/ringdown/fit.py
@@ -1911,6 +1911,7 @@ def from_imr_result(
         set_target: bool = True,
         update_model: bool = True,
         duration: float | bool = "auto",
+        imr_kws: dict | None = None,
         data_kws: dict | None = None,
         peak_kws: dict | None = None,
         acf_kws: dict | None = None,
@@ -1932,6 +1933,7 @@ def from_imr_result(
             approximant=approximant,
             reference_frequency=reference_frequency,
             psds=psds,
+            **(imr_kws or {})
         )
         imr = fit.imr_result
 
diff --git a/ringdown/imr.py b/ringdown/imr.py
index f4066228..f96185c0 100644
--- a/ringdown/imr.py
+++ b/ringdown/imr.py
@@ -446,7 +446,8 @@ def ifos(self):
         """List of detectors in the DataFrame."""
         # try config first
         if "detectors" in self.attrs.get("config", {}):
-            return self.attrs["config"]["detectors"]
+            return [k.replace("'", "") for k in self.attrs["config"]['detectors']]
+            # return self.attrs["config"]['detectors']
         time_keys = [k for k in self.columns if TIME_KEY in k]
         return [k.replace(TIME_KEY, "") for k in time_keys]
 
@@ -803,9 +804,15 @@ def get_waveforms(
                     logger.warning("time arrays have inconsistent lengths")
 
         for _, sample in tqdm(df.iterrows(), **tqdm_kws):
-            h = waveforms.get_detector_signals(
-                times=time, ifos=ifos, **sample, **kws
+            if np.array([self.reference_frequency < self.minimum_frequency[ifo] for ifo in ifos]).any():
+                h = waveforms.get_detector_signals(
+                times=time, ifos=ifos, f_low=self.minimum_frequency['waveform'],
+                **sample, **kws
             )
+            else:
+                h = waveforms.get_detector_signals(
+                    times=time, ifos=ifos, **sample, **kws
+                )
             for ifo in ifos:
                 if condition:
                     # look for target time 't0' which can be a dict with
@@ -1169,7 +1176,7 @@ def from_pesummary(
                 logger.info(f"no group provided; using {group}")
             config = pe.config.get(group, {}).get("config", {})
             p = {
-                i: data.PowerSpectrum(p).fill_low_frequencies().gate()
+                i: data.PowerSpectrum(p).fill_low_frequencies().gate().interpolate_to_index()
                 for i, p in pe.psd.get(group, {}).items()
             }
             attrs = (attrs or {}).update({"config": config})
@@ -1205,7 +1212,7 @@ def from_pesummary(
                             )
                 if "psds" in f[group]:
                     p = {
-                        i: data.PowerSpectrum(p).fill_low_frequencies().gate()
+                        i: data.PowerSpectrum(p).fill_low_frequencies().gate().interpolate_to_index()
                         for i, p in f[group]["psds"].items()
                     }
                 else:
diff --git a/ringdown/utils/utils.py b/ringdown/utils/utils.py
index 9df220cd..4e59c274 100644
--- a/ringdown/utils/utils.py
+++ b/ringdown/utils/utils.py
@@ -373,8 +373,8 @@ def get_bilby_dict(d):
     """Parse bilby-style data dict string.
     """
     if isinstance(d, str):
-        chars_to_remove = "'{}"
+        chars_to_remove = " '{}"
         translation_table = str.maketrans('', '', chars_to_remove)
         d = {k.translate(translation_table): v.translate(translation_table)
-             for k, v in [i.split(':') for i in d.split(',')]}
+             for k, v in [i.split(':') for i in d.split(',') if ':' in i] }
     return d