diff --git a/CMakeLists.txt b/CMakeLists.txt
index d01ccaf..102f569 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -34,6 +34,7 @@ list(APPEND inspectrum_sources
     inputsource.cpp
     memory_sink_impl.cc
     memory_source_impl.cc
+    plot.cpp
     plotview.cpp
     samplebuffer.cpp
     spectrogramcontrols.cpp
diff --git a/plot.cpp b/plot.cpp
index 9643982..fc58d8e 100644
--- a/plot.cpp
+++ b/plot.cpp
@@ -17,4 +17,13 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "plot.h"
\ No newline at end of file
+#include "plot.h"
+
+void Plot::paintBack(QPainter &painter, QRect &rect, range_t<off_t> sampleRange)
+{
+    painter.save();
+    QPen pen(Qt::white, 1, Qt::DashLine);
+    painter.setPen(pen);
+    painter.drawLine(rect.left(), rect.center().y(), rect.right(), rect.center().y());
+    painter.restore();
+}
\ No newline at end of file
diff --git a/plot.h b/plot.h
index c9d2c3e..c635c00 100644
--- a/plot.h
+++ b/plot.h
@@ -27,7 +27,7 @@ class Plot : public QObject
 {
 
 public:
-    virtual void paintBack(QPainter &painter, QRect &rect, range_t<off_t> sampleRange) = 0;
+    virtual void paintBack(QPainter &painter, QRect &rect, range_t<off_t> sampleRange);
     virtual void paintMid(QPainter &painter, QRect &rect, range_t<off_t> sampleRange) = 0;
     virtual void paintFront(QPainter &painter, QRect &rect, range_t<off_t> sampleRange) = 0;
     int height() const { return _height; };
diff --git a/plotview.cpp b/plotview.cpp
index 5442835..1bf0442 100644
--- a/plotview.cpp
+++ b/plotview.cpp
@@ -28,6 +28,7 @@
 #include "grsamplebuffer.h"
 #include "memory_sink.h"
 #include "memory_source.h"
+#include "spectrogramplot.h"
 #include "traceplot.h"
 
 PlotView::PlotView()
diff --git a/spectrogramplot.cpp b/spectrogramplot.cpp
index c7879d5..bacb1c3 100644
--- a/spectrogramplot.cpp
+++ b/spectrogramplot.cpp
@@ -115,11 +115,6 @@ void SpectrogramPlot::mousePressEvent(QMouseEvent *event)
     update();
 }
 
-void SpectrogramPlot::paintBack(QPainter &painter, QRect &rect, range_t<off_t> sampleRange)
-{
-
-}
-
 void SpectrogramPlot::paintMid(QPainter &painter, QRect &rect, range_t<off_t> sampleRange)
 {
 
diff --git a/spectrogramplot.h b/spectrogramplot.h
index 624f8b0..b6c8b9e 100644
--- a/spectrogramplot.h
+++ b/spectrogramplot.h
@@ -40,7 +40,6 @@ public:
     SpectrogramPlot();
     ~SpectrogramPlot();
 
-    void paintBack(QPainter &painter, QRect &rect, range_t<off_t> sampleRange);
     void paintMid(QPainter &painter, QRect &rect, range_t<off_t> sampleRange);
     void paintFront(QPainter &painter, QRect &rect, range_t<off_t> sampleRange);
 
diff --git a/traceplot.cpp b/traceplot.cpp
index 9387f6f..133c557 100644
--- a/traceplot.cpp
+++ b/traceplot.cpp
@@ -24,11 +24,6 @@ TracePlot::TracePlot(std::shared_ptr<AbstractSampleSource> source) : sampleSourc
 
 }
 
-void TracePlot::paintBack(QPainter &painter, QRect &rect, range_t<off_t> sampleRange)
-{
-
-}
-
 void TracePlot::paintMid(QPainter &painter, QRect &rect, range_t<off_t> sampleRange)
 {
 	auto firstSample = sampleRange.minimum;
diff --git a/traceplot.h b/traceplot.h
index 4e34eb9..4a7097e 100644
--- a/traceplot.h
+++ b/traceplot.h
@@ -30,7 +30,6 @@ class TracePlot : public Plot
 public:
 	TracePlot(std::shared_ptr<AbstractSampleSource> source);
 
-    void paintBack(QPainter &painter, QRect &rect, range_t<off_t> sampleRange);
     void paintMid(QPainter &painter, QRect &rect, range_t<off_t> sampleRange);
     void paintFront(QPainter &painter, QRect &rect, range_t<off_t> sampleRange);