diff --git a/csdr/chain/fft.py b/csdr/chain/fft.py
index 3cc2344..09d47cd 100644
--- a/csdr/chain/fft.py
+++ b/csdr/chain/fft.py
@@ -4,11 +4,16 @@ from pycsdr import Fft, LogAveragePower, FftExchangeSides, CompressFftAdpcm
 
 class FftChain(Chain):
     def __init__(self, fft_size, fft_block_size, fft_averages, fft_compression):
+        self.fft = Fft(size=fft_size, every_n_samples=int(fft_block_size))
+        self.logAveragePower = LogAveragePower(add_db=-70, fft_size=fft_size, avg_number=fft_averages)
+        self.fftExchangeSides = FftExchangeSides(fft_size=fft_size)
         workers = [
-            Fft(size=fft_size, every_n_samples=int(fft_block_size)),
-            LogAveragePower(add_db=-70, fft_size=fft_size, avg_number=fft_averages),
-            FftExchangeSides(fft_size=fft_size),
+            self.fft,
+            self.logAveragePower,
+            self.fftExchangeSides,
         ]
+        self.compressFftAdpcm = None
         if fft_compression == "adpcm":
-            workers += [CompressFftAdpcm(fft_size=fft_size)]
+            self.compressFftAdpcm = CompressFftAdpcm(fft_size=fft_size)
+            workers += [self.compressFftAdpcm]
         super().__init__(*workers)
diff --git a/csdr/csdr.py b/csdr/csdr.py
index 385688d..ec62f62 100644
--- a/csdr/csdr.py
+++ b/csdr/csdr.py
@@ -112,6 +112,7 @@ class dsp(object):
         self.secondary_fft_size = 1024
         self.secondary_process_fft = None
         self.secondary_process_demod = None
+        self.fft_voverlap_factor = 0
         self.pipe_names = {
             "bpf_pipe": Pipe.WRITE,
             "shift_pipe": Pipe.WRITE,
@@ -523,8 +524,11 @@ class dsp(object):
             return (self.secondary_fft_size / 2) + (10 / 2)
 
     def set_samp_rate(self, samp_rate):
+        if self.samp_rate == samp_rate:
+            return
         self.samp_rate = samp_rate
         self.calculate_decimation()
+        self.update_fft_averages()
         if self.running:
             self.restart()
 
@@ -639,14 +643,35 @@ class dsp(object):
         return self.demodulator
 
     def set_fft_size(self, fft_size):
+        if self.fft_size == fft_size:
+            return
         self.fft_size = fft_size
+        self.update_fft_averages()
         self.restart()
 
     def set_fft_fps(self, fft_fps):
+        if self.fft_fps == fft_fps:
+            return
         self.fft_fps = fft_fps
+        self.update_fft_averages()
         self.restart()
 
+    def set_fft_voverlap_factor(self, fft_voverlap_factor):
+        if self.fft_voverlap_factor == fft_voverlap_factor:
+            return
+        self.fft_voverlap_factor = fft_voverlap_factor
+        self.update_fft_averages()
+
+    def update_fft_averages(self):
+        self.set_fft_averages(
+            int(round(1.0 * self.samp_rate / self.fft_size / self.fft_fps / (1.0 - self.fft_voverlap_factor)))
+            if self.fft_voverlap_factor > 0
+            else 0
+        )
+
     def set_fft_averages(self, fft_averages):
+        if self.fft_averages == fft_averages:
+            return
         self.fft_averages = fft_averages
         self.restart()
 
diff --git a/owrx/fft.py b/owrx/fft.py
index 3486983..85f6d45 100644
--- a/owrx/fft.py
+++ b/owrx/fft.py
@@ -34,29 +34,15 @@ class SpectrumThread(csdr.output, SdrSourceEventClient):
         dsp.setSocketClient(self.sdrSource.getSocketClient())
         dsp.set_demodulator("fft")
 
-        def set_fft_averages(key, value):
-            samp_rate = props["samp_rate"]
-            fft_size = props["fft_size"]
-            fft_fps = props["fft_fps"]
-            fft_voverlap_factor = props["fft_voverlap_factor"]
-
-            dsp.set_fft_averages(
-                int(round(1.0 * samp_rate / fft_size / fft_fps / (1.0 - fft_voverlap_factor)))
-                if fft_voverlap_factor > 0
-                else 0
-            )
-
         self.subscriptions = [
             props.wireProperty("samp_rate", dsp.set_samp_rate),
             props.wireProperty("fft_size", dsp.set_fft_size),
             props.wireProperty("fft_fps", dsp.set_fft_fps),
             props.wireProperty("fft_compression", dsp.set_fft_compression),
             props.wireProperty("temporary_directory", dsp.set_temporary_directory),
-            props.filter("samp_rate", "fft_size", "fft_fps", "fft_voverlap_factor").wire(set_fft_averages),
+            props.wireProperty("fft_voverlap_factor", dsp.set_fft_voverlap_factor),
         ]
 
-        set_fft_averages(None, None)
-
         dsp.csdr_dynamic_bufsize = props["csdr_dynamic_bufsize"]
         dsp.csdr_print_bufsizes = props["csdr_print_bufsizes"]
         dsp.csdr_through = props["csdr_through"]