Create a new layer. Use your "Rectangle Selection Tool" to make the outside parameter of the screen. Then flood fill it with the "Fading-White" gradient at 180 angle. Drop the layer opacity down to 18. Create another layer and set your foreground color to #000000. Then flood fill the new layer with the "Fading-Foreground" gradient, angle set to 180. Drop that layer opacity to 52.

Create a new layer. With the TV screen still selected Selections > Modify > Contract set the number of pixels to 7. Flood fill this layer with the "Fading-White" gradient, angle set to 0. Drop the opacity pf the layer to 18. Create a new layer. Flood fill with the "Fading-Foreground" gradient, angle set to 0 (foreground color should still be #000000). Drop the opacity of the layer to 54

Now lets make the selection for the speakers. Select the layer that holds the basic shape of the TV. Then Selections > Select All > Selections > Float. This should select the shape. Then Selections > Modify > Contract. Set the "Number of Pixels" to 3. Now use your "Rectangle Selection Tool" and remove a chunk of the selection around the dark border (around the screen) by holding CTRL while you drag the mouse. Do the same thing under the dark border but remove a little less. Check the examples below.

Now we need to create a pattern for the speakers. Create a new document 40x40px with a transparent background. Then grab your paint brush set the size to 10 and the shape to square. Turn your grid on and have it set to 5x5px. Make a pattern like the one below.

Select your TV and goto your patterns. Pick the pattern you just made (it will be above the stock patterns). Set the scale of the pattern to 19 Then flood fill your speaker selection. Knock the opacity of the speaker layer down to about 30.