View Full Version : [solved]Question: Microphone "passthrough"
10-17-2010, 07:45 AM
Quick little question: Is there a way to take the input from the onboard microphone and send it out on the earphone port? Essentially a "hearing aid" or remote microphone app?
I want to do it so I can use a 3.5MM male-male connector to connect it to the line-in jack on my desktop, when my other mics aren't available.
I did this with my last mp3 player, an iRiver H320 with Rockbox on it - It worked out great. I'm just trying to figure out how I can do it with my N900.
10-17-2010, 07:49 AM
i know this is possible on a full pulseaudio installation, where you set the output as a monitor of an input, but im not sure if maemo's stripped down pulseaudio system has that feature
10-17-2010, 08:04 AM
arecord | aplay, monitor how the phone app changes alsa switches to reroute audio to the earphone.
I'm not sure how you could remove the delay though.
10-17-2010, 09:14 AM
assuming you have gstreamer tools isntalled, at a terminal prompt:
gst-launch pulsesrc device=source.hw0 ! audioconvert ! volume volume=2.5 ! pulsesink device=sink.hw0
As M.AG says you will experience a delay between audio in and routing out but depending on the applicaiton you want to put it to this may not be a killer for you.
I've added a dash of volume as I find the output a little quiet otherwise. Feel free to change the value to taste.
10-18-2010, 03:03 AM
mr id's solution works, and isn't terribly laggy. I'll call that good.
11-24-2010, 10:35 PM
this is a brilliant idea! one question though: is it necessary to "deactivate" it afterwards and how? i've just found out about this thread and i'll give it a try after i find out if deactivation is needed.
11-25-2010, 03:42 AM
no. but you would terminate it though. ctrl+c at the terminal where it's running (or just close the terminal window).
After some experiments, I found out the following command that allowed me to make my bluetooth hands free work like talkietalkie with my n900, having headset:
gst-launch pulsesrc device=source.hw1 ! audioconvert ! volume volume=100 ! pulsesink device=sink.hw0 pulsesrc device=source.hw0 ! audioconvert ! volume volume=100 ! pulsesink device=sink.hw1
also if you want only to listen from the bluetooth handsfree microphone to the phone:
gst-launch pulsesrc device=source.hw1 ! audioconvert ! volume volume=100 ! pulsesink device=sink.hw0
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