diff --git a/widegraph.ui b/widegraph.ui
index 3c05d09..e3d67c8 100644
--- a/widegraph.ui
+++ b/widegraph.ui
@@ -174,7 +174,7 @@
                 <x>0</x>
                 <y>0</y>
                 <width>267</width>
-                <height>338</height>
+                <height>370</height>
                </rect>
               </property>
               <layout class="QVBoxLayout" name="verticalLayout_8">
@@ -321,7 +321,29 @@
                      <number>10</number>
                     </property>
                     <property name="value">
-                     <number>2600</number>
+                     <number>2500</number>
+                    </property>
+                   </widget>
+                  </item>
+                  <item>
+                   <widget class="QSpinBox" name="filterCenterSpinBox">
+                    <property name="enabled">
+                     <bool>false</bool>
+                    </property>
+                    <property name="suffix">
+                     <string> Hz</string>
+                    </property>
+                    <property name="prefix">
+                     <string>Center: </string>
+                    </property>
+                    <property name="maximum">
+                     <number>5000</number>
+                    </property>
+                    <property name="singleStep">
+                     <number>10</number>
+                    </property>
+                    <property name="value">
+                     <number>1000</number>
                     </property>
                    </widget>
                   </item>
@@ -825,6 +847,9 @@
                     <property name="alignment">
                      <set>Qt::AlignCenter</set>
                     </property>
+                    <property name="buttonSymbols">
+                     <enum>QAbstractSpinBox::PlusMinus</enum>
+                    </property>
                     <property name="suffix">
                      <string>%</string>
                     </property>