A flat speaker includes a casing with a display window, a vibratory sound panel mounted to the display window and having a display region and an exciter mount region, a display screen disposed internally of the display region, and an exciter mounted to the inner surface of the exciter mount region. A dust barrier is disposed to isolate a first space defined between the display region and the display screen from a second space surrounding the first space. The dust barrier has a dust barrier member disposed between the display region and the exciter mount region and extending across the vibratory sound panel to inhibit dust particles from moving from said exciter mount region to said display region within said casing. The dust barrier member is yieldingly deformable in response to vibration of said vibratory sound panel.