...
  <Application.Resources>
<Style x:Key="mainFrameStyle" TargetType="phone:PhoneApplicationFrame">
      <Setter Property="Template">
        <Setter.Value>
          <ControlTemplate TargetType="phone:PhoneApplicationFrame">
            <Border x:Name="ClientArea"
                        BorderBrush="{TemplateBinding BorderBrush}"
                        BorderThickness="{TemplateBinding BorderThickness}"
                        Background="{TemplateBinding Background}"
                        HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
                        VerticalAlignment="{TemplateBinding VerticalAlignment}">
              <Grid>...
                <Grid x:Name="audioPanel" Grid.RowSpan="2" VerticalAlignment="Bottom">
                    .....
                </Grid>
              </Grid>
            </Border>
          </ControlTemplate>
        </Setter.Value>
      </Setter>
    </Style>
...
  </Application.Resources>