Acer Extensa 355 Features Manual page 17

System Tour
2.8 Audio
Standard notebook configuration includes 16-bit stereo
audio which is compatible with Sound Blaster and Sound
Blaster Pro. A single speaker found on the right side of the
palm rest direct sound towards you which allows for
excellent sound output.
Built-in Speaker
Besides the built-in speaker, there are audio ports on the
rear panel of the notebook. See section 4.5 for more
information.
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