Interface OEM Bluetooth Microphone with Aftermarket HU - Subaru Impreza WRX STI Forums: IWSTI.com
STI Forum
Join
Start New Thread Create Account Advertise FAQ Members List Contact
Interface OEM Bluetooth Microphone with Aftermarket HU
Interface OEM Bluetooth Microphone with Aftermarket HU
Go Back   STI Forums > > > > Interface OEM Bluetooth Microphone with Aftermarket HU
Reply
 
Thread Tools
Old 03-13-12, 08:35 AM   #1
aacordon
Contributor
Feedback Score: 0 reviews
 
Car: DGM 11' STi Sedan
Fav Mod: Avic z120BT
My Threads
Posts: 73
My Subaru Parts for sale

Join Date: Aug 2010
Location: Los Angeles
aacordon is an unknown quantity at this point
Default Interface OEM Bluetooth Microphone with Aftermarket HU

As stated in the title, the goal is to be able to use the oem overhead bluetooth microphone with aftermarket headunits. This is for those who prefer not to have a microphone on their dash or steering column.

The primary goal is to get this working with as little modification to the vehicles hardware (harnesses, circuitry, etc...).

It is actually really simple to get the stock Bluetooth mic working. (the following will be avic specific but may be applicable to others)

For the 2.5mm mic input on the new HU,
-TIP is a 5v source
-Sleeve is the mic input

Follow the following diagram carefully. Credit to SVXdc
Quote:
Code:
 
   Subaru's pin numbering
  (viewing rear of OEM HU or wires side of car's harness):
   _   ________________   _
  | ---                --- |
  | 8  7  6  5  4  3  2  1 |
  |16 15 14 13 12 11 10  9 |
   ------------------------
   
  Corresponding numbering on PC board:
    2  4  6  8 10 12 14 16
    1  3  5  7  9 11 13 15
   
  PCB   Subaru   Description                  OEM Color
  ---   ------   --------------------------   ------------
  16       1     Mic In (+)                   White/Black
  14       2     Mic Detect A                 Gray
  12       3     Aux In Left +                Yellow
  10       4     Aux In Right +               Blue
   8       5     Subwoofer Amp Turn-On        -
   6       6     Subwoofer Out + (positive)   -
   4       7     Mic Shield                   -
   2       8     NC                           -
   
  15       9     Mic In Ground (-)            Violet/Red
  13      10     Mic Detect B                 Black/Blue
  11      11     Aux Audio Ground             Shield
   9      12     Aux Enable                   Black/Orange
   7      13     Subwoofer Shield             -
   5      14     Subwoofer Out - (inverted)   -
   3      15     NC                           -
   1      16     NC                           -
Connect Pin 1 to the mic input of the HU
Connect Pin 2 to the 5v source
Connect Pin 9 to Ground (either chasis or one of your ground wires)


Since i did not have a nice harness plug, I made do with crimp pins which fit nicely in the cars plug. Those crimp pins were wired up with a 2.5mm jack that was connected to the back of the HU.

The following is just to show the amplifier circuit in the car.

Per the picture below.

Red = Vcc, 5 volts was measured as an output from the stock unit. The Avic MIC out provides 5 volts.
Yellow = Vout (output from amplifier)
Blue = GND

http://img2.imageshack.us/img2/2123/...crophonepc.jpg

Below is the amplifier schematic. All the values are included, except for the capacitors.


Last edited by aacordon; 03-13-12 at 11:38 PM. Reason: Added schematic, Determined Voltages
aacordon is offline  
Likes 0 Dislikes 0
 
Reply With Quote
Sponsored Links
Advertisement
 
Old 03-14-12, 11:19 PM   #2
SVXdc
Advanced Contributor Level 2
Feedback Score: 0 reviews
 
Car: 1996 SVX L AWD
My Threads
Posts: 254
My Subaru Parts for sale

Join Date: Mar 2005
Location: Atlanta, GA
SVXdc is an unknown quantity at this point
Default Re: Interface OEM Bluetooth Microphone with Aftermarket HU

Great job! Here's a pic of the factory 16-pin mic/aux harness plug:
Pin 2 should actually be named "MIC B+". It is an output from the OEM HU that supplies +5V power to the OEM mic module's amplifier circuit.

The car's harness connects pin 10, "MIC DET", to ground. The HU uses that to detect that a mic is connected and also to enable the +5V power supply on pin 2. Pin 10 won't be needed when interfacing the factory mic to an aftermarket HU (the pin 10 wire does not go to the OEM mic).

Also, as I mentioned in aacordon's earlier thread, the subwoofer output is not present on HUs in Imprezas. Only in some Foresters.

So you've tried this on an AVIC? People aren't complaining that you sound too loud or distorted? No complaints of excessive wind noise?
__________________
David C.
1996 Laguna Blue Pearl SVX L AWD
Useful Subaru pin-outs and other info

Last edited by SVXdc; 05-28-12 at 12:56 PM.
SVXdc is offline  
Likes 0 Dislikes 0
 
Reply With Quote
Old 03-15-12, 04:16 PM   #3
aacordon
Contributor
Feedback Score: 0 reviews
 
Car: DGM 11' STi Sedan
Fav Mod: Avic z120BT
My Threads
Posts: 73
My Subaru Parts for sale

Join Date: Aug 2010
Location: Los Angeles
aacordon is an unknown quantity at this point
Default Re: Interface OEM Bluetooth Microphone with Aftermarket HU

I've primarly tested it on the voice recognition so far, and it has worked out. I need to test it with someone in a controlled environment first. My only attempt at a call was while driving through an area with bad recepetion, so the results were marginal and skewed.

If there is distortion, it could be due to gain as the HU most definately has its own amp within it and it could be clipping the sound.

If gain turns out to be the issue, I can try a simple voltage divider using a pot to determine what the max/min input level to the HU are.

Last edited by aacordon; 03-15-12 at 04:34 PM. Reason: Grammar
aacordon is offline  
Likes 0 Dislikes 0
 
Reply With Quote
Sponsored Links
Advertisement
 
Old 03-15-12, 04:25 PM   #4
Rem1993
Master Contributor Level 1
Feedback Score: 3 reviews
 
Car: 11 STI Sedan PPB
Fav Mod: Rotated Turbo Kitt
My Threads
Posts: 766
My Subaru Parts for sale

Join Date: Dec 2009
Location: Northern NJ
Rem1993 is on a distinguished road
Default

Good job
Rem1993 is offline  
Likes 0 Dislikes 0
 
Reply With Quote
Old 03-16-12, 09:01 AM   #5
aacordon
Contributor
Feedback Score: 0 reviews
 
Car: DGM 11' STi Sedan
Fav Mod: Avic z120BT
My Threads
Posts: 73
My Subaru Parts for sale

Join Date: Aug 2010
Location: Los Angeles
aacordon is an unknown quantity at this point
Default Re: Interface OEM Bluetooth Microphone with Aftermarket HU

Results from my test are as follows:

There is alot of Backround noise which muffles my voice. Sound like wind even though the car is at a standstill with windows up.

Echoes are apparent and even worse when echo canceling is turned off.

There may be some clipping if i yell.


I will try and attenuate the mic input tonight and find a good level.

From the circuit, the mic has a gain of 100, centered at 0v.

Last edited by aacordon; 03-16-12 at 09:08 AM.
aacordon is offline  
Likes 0 Dislikes 0
 
Reply With Quote
Old 09-24-12, 07:10 AM   #6
corner7246
Active Participant
Feedback Score: 0 reviews
 
Fav Mod: Coming Soon
My Threads
Posts: 8
My Subaru Parts for sale

Join Date: Sep 2012
corner7246 is an unknown quantity at this point
Default Re: Interface OEM Bluetooth Microphone with Aftermarket HU

So here's my question. If I need +5v in order to get the OEM mic to operate I could steal 12v from the map lights and wire in a resistor (messy) or locate a different +5v in the car to tie into and run a fresh cable.

Where are you guys getting your +5v from without the factory HU?
corner7246 is offline  
Likes 0 Dislikes 0
 
Reply With Quote
Old 09-24-12, 07:55 AM   #7
corner7246
Active Participant
Feedback Score: 0 reviews
 
Fav Mod: Coming Soon
My Threads
Posts: 8
My Subaru Parts for sale

Join Date: Sep 2012
corner7246 is an unknown quantity at this point
Default Re: Interface OEM Bluetooth Microphone with Aftermarket HU

Anyone know where I can get a wiring diagram for a 2012 WRX?
corner7246 is offline  
Likes 0 Dislikes 0
 
Reply With Quote
Old 09-24-12, 09:40 AM   #8
101101
Advanced Contributor Level 3
Feedback Score: 6 reviews
 
Fav Mod: HPDE
My Threads
Posts: 355
My Subaru Parts for sale

Join Date: Jan 2011
Location: NC
101101 is an unknown quantity at this point
Default Re: Interface OEM Bluetooth Microphone with Aftermarket HU

Quote:
Originally Posted by corner7246 View Post
So here's my question. If I need +5v in order to get the OEM mic to operate I could steal 12v from the map lights and wire in a resistor (messy)
[...]
I'd wire in a voltage regulator off the map lights before I tried to use a resistor to drop it to 5v.
101101 is offline  
Likes 0 Dislikes 0
 
Reply With Quote
Old 09-24-12, 10:30 AM   #9
corner7246
Active Participant
Feedback Score: 0 reviews
 
Fav Mod: Coming Soon
My Threads
Posts: 8
My Subaru Parts for sale

Join Date: Sep 2012
corner7246 is an unknown quantity at this point
Default Re: Interface OEM Bluetooth Microphone with Aftermarket HU

I think I was misreading this. What aacordon is saying is that the aftermarket radio supplies you the 5v you need on the tip of the jack and the input from the mic is the shield. Connect the last cable to chassis ground and bam you're in buisness..

I'll have to try this once I get home.
corner7246 is offline  
Likes 0 Dislikes 0
 
Reply With Quote
Old 09-24-12, 09:12 PM   #10
aacordon
Contributor
Feedback Score: 0 reviews
 
Car: DGM 11' STi Sedan
Fav Mod: Avic z120BT
My Threads
Posts: 73
My Subaru Parts for sale

Join Date: Aug 2010
Location: Los Angeles
aacordon is an unknown quantity at this point
Default Re: Interface OEM Bluetooth Microphone with Aftermarket HU

Quote:
Originally Posted by corner7246 View Post
I think I was misreading this. What aacordon is saying is that the aftermarket radio supplies you the 5v you need on the tip of the jack and the input from the mic is the shield. Connect the last cable to chassis ground and bam you're in buisness..

I'll have to try this once I get home.
Yup thats correct. However the oem mic has a amplifier, and then the aftermarket headunit has its own amplifier. The problem with this is that the overall gain of the mic input is actually the (gain of oem amp)*(gain of internal amp) and clipping occurrs. The mic has to attenuated by 100 before going back to the HU. Or the over head mic will have to be rewired to by pass the amp.

This along with getting pcbs fabricated for the av connectors are on a TO-DO list i have that will have to wait till january when im taking a qtr off from my Masters program.
aacordon is offline  
Likes 0 Dislikes 0
 
Reply With Quote
Sponsored Links
Advertisement
 
Reply

Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
FS (USA,CA): Garage Sale **NEW ITEMS** jaredperry Part Outs / Multiple Parts 15 04-15-12 12:47 PM
SOLD: 08 STI OEM Navigation Head Unit w/bluetooth and microphone adapter gaguilarsti Security / ICE For Sale 10 02-15-11 01:54 PM
OEM iPod interface power/not connecting? Sabrewings GR-ICE/Security 1 08-10-10 03:42 PM
Fs:(pa)07 sti partial partout,lots of oem and aftermarket parts needed to get rid of o0oso0wreckless Part Outs / Multiple Parts 35 06-03-10 04:48 PM


New To Site? Need Help? More

All times are GMT -8. The time now is 07:38 PM.


Powered by vBulletin
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Designed & Powered by Domain Architect
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.