Jens Olsson

I had some mess with my headphones and microphone on my Acer 5738ZG Dolby while using Ubuntu. This may help you fix it, at least helped me. Right click on your speaker icon just beside the clock then Open Volume Control. Then you click on settings… Check all that are unchecked and close. Take surround to top and un mark mute. Then to make the speakers quiet just mute front. Do also not forget to make sure your headphones are checked under switch.

Then to microphone, take front mick up to the top and un mark mute. Then go to Alternative and select input source to Front Mic. If you wanna boost your microphone just increase front mic boost, but be careful if you use speakers you will get consecutive working.

3 screens from mine volume control while using headphones: