diff --git a/frequencydemod.cpp b/frequencydemod.cpp
index de95ccd..17bdf6b 100644
--- a/frequencydemod.cpp
+++ b/frequencydemod.cpp
@@ -30,7 +30,7 @@ void FrequencyDemod::work(void *input, void *output, int count, size_t sampleid)
 {
     auto in = static_cast<std::complex<float>*>(input);
     auto out = static_cast<float*>(output);
-    freqdem fdem = freqdem_create(0.05f);
+    freqdem fdem = freqdem_create(relativeBandwidth() / 2.0);
     for (int i = 0; i < count; i++) {
         freqdem_demodulate(fdem, in[i], &out[i]);
     }
diff --git a/samplebuffer.h b/samplebuffer.h
index e3eafff..047e498 100644
--- a/samplebuffer.h
+++ b/samplebuffer.h
@@ -45,6 +45,6 @@ public:
     };
 
     float relativeBandwidth() {
-        return 1;
+        return src->relativeBandwidth();
     }
 };
diff --git a/spectrogramplot.cpp b/spectrogramplot.cpp
index 9b43762..975c69b 100644
--- a/spectrogramplot.cpp
+++ b/spectrogramplot.cpp
@@ -343,7 +343,7 @@ void SpectrogramPlot::tunerMoved()
 {
     tunerTransform->setFrequency(getTunerPhaseInc());
     tunerTransform->setTaps(getTunerTaps());
-    tunerTransform->setRelativeBandwith(tuner.deviation() * 2.0 / getStride());
+    tunerTransform->setRelativeBandwith(tuner.deviation() * 2.0 / height());
 
     // TODO: for invalidating traceplot cache, this shouldn't really go here
     QPixmapCache::clear();