diff --git a/sdrbase/dsp/dspdevicesinkengine.cpp b/sdrbase/dsp/dspdevicesinkengine.cpp
index 53d39895b..82d65701a 100644
--- a/sdrbase/dsp/dspdevicesinkengine.cpp
+++ b/sdrbase/dsp/dspdevicesinkengine.cpp
@@ -479,12 +479,12 @@ void DSPDeviceSinkEngine::handleSynchronousMessages()
 	{
 		BasebandSampleSource* source = ((DSPAddBasebandSampleSource*) message)->getSampleSource();
 		m_basebandSampleSources.push_back(source);
+        DSPSignalNotification notif(m_sampleRate, m_centerFrequency);
+        source->handleMessage(notif);
 		checkNumberOfBasebandSources();
 
         if (m_state == StRunning)
         {
-            DSPSignalNotification notif(m_sampleRate, m_centerFrequency);
-            source->handleMessage(notif);
             source->start();
         }
 	}
@@ -503,12 +503,12 @@ void DSPDeviceSinkEngine::handleSynchronousMessages()
 	{
 		ThreadedBasebandSampleSource *threadedSource = ((DSPAddThreadedBasebandSampleSource*) message)->getThreadedSampleSource();
 		m_threadedBasebandSampleSources.push_back(threadedSource);
+        DSPSignalNotification notif(m_sampleRate, m_centerFrequency);
+        threadedSource->handleSourceMessage(notif);
 		checkNumberOfBasebandSources();
 
         if (m_state == StRunning)
         {
-            DSPSignalNotification notif(m_sampleRate, m_centerFrequency);
-            threadedSource->handleSourceMessage(notif);
             threadedSource->start();
         }
 	}
diff --git a/sdrbase/dsp/dspdevicesourceengine.cpp b/sdrbase/dsp/dspdevicesourceengine.cpp
index 8d77af6e0..a641de94e 100644
--- a/sdrbase/dsp/dspdevicesourceengine.cpp
+++ b/sdrbase/dsp/dspdevicesourceengine.cpp
@@ -559,6 +559,13 @@ void DSPDeviceSourceEngine::handleSynchronousMessages()
 	{
 		BasebandSampleSink* sink = ((DSPAddBasebandSampleSink*) message)->getSampleSink();
 		m_basebandSampleSinks.push_back(sink);
+        // initialize sample rate and center frequency in the sink:
+        DSPSignalNotification msg(m_sampleRate, m_centerFrequency);
+        sink->handleMessage(msg);
+        // start the sink:
+        if(m_state == StRunning) {
+            sink->start();
+        }
 	}
 	else if (DSPRemoveBasebandSampleSink::match(*message))
 	{
@@ -578,7 +585,9 @@ void DSPDeviceSourceEngine::handleSynchronousMessages()
 		DSPSignalNotification msg(m_sampleRate, m_centerFrequency);
 		threadedSink->handleSinkMessage(msg);
 		// start the sink:
-		threadedSink->start();
+        if(m_state == StRunning) {
+            threadedSink->start();
+        }
 	}
 	else if (DSPRemoveThreadedBasebandSampleSink::match(*message))
 	{