# DIY bluetooth mic gain adjustment....?



## eskateboarding7 (Mar 18, 2009)

I'm dealing with a w505 and a KCE-400BT. As most of you know, the w505 is a 2008 model and the 400BT is 2009; so while still compatible, 2008 headunits do not have full feature controls such as mic gain adjustment. 

Point: What I want to know is if anyone has any reason to believe why a potentiometer or something similar would not be able to be used inline between the mic and where it makes its connection. Conceptually I believe this will work. Any insight is greatly appreciated.


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## eskateboarding7 (Mar 18, 2009)

Also I'm assuming that since we are dealing with AC voltage that the pot would only need to be placed on the signal wire (Alpine BT mic is a 2 pin configuration), is this logic correct?


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## eskateboarding7 (Mar 18, 2009)

bump


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## deesz (Feb 1, 2010)

i dont think so... if you added a potentiometer you would only be able to lower it from the highest point. 

think about it just like a radio. 
it was designed to play x amount loud but you cant go past x amount unless you add an amp. so essentially you could make it louder if you added an amp to it.


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## eskateboarding7 (Mar 18, 2009)

deesz said:


> i dont think so... if you added a potentiometer you would only be able to lower it from the highest point.
> 
> think about it just like a radio.
> it was designed to play x amount loud but you cant go past x amount unless you add an amp. so essentially you could make it louder if you added an amp to it.


That's exactly what I want to do, I should have specified. The mic is excessively sensitive and the those on the other end of the call can hear themselves echoing due to the mic picking up the conversation being output. Anyway, I tried this and I either used a crap pot or didn't hook it up correctly. This sounds stupid, but is the ground for a pot supposed to go to chassis ground or AC signal ground....?


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## SQ Man (Nov 27, 2008)

You can't do that, the mic used is in the phone kit is an electret capsule, which needs a DC power bias to operate. By inserting the pot all you are doing is reducing the DC bias voltage, not the output signal.


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