[Jalapeno]

aacordon, corner,

Resurrecting this thread as I'm interested to hear about any progress you guys may have made. I'm thinking of installing an aftermarket head unit but I want to keep the stock bluetooth speaker, or install an aftermarket one in the stock location at the very least. Also, I'd like to try and keep the stock USB port and AUX port if possible. I have an interest in this stuff but I'm not very savy when it comes to electronics, which equates to me being useless in this arena. :lol:

Anyhow, interested to see the results of your guys' hard work.

Regards,
Joel

 

[Lvkeith]

Any way we can get the images hosted again? Looking for the mic amplifier bypass please.

Thanks!

 

[red_five]

I joined the forum just to add some info to the thread. I recently bought a 2014 Outback with the nav system, and getting the factory mic working with a potential aftermarket HU upgrade is of interest to me. Based on the diagrams from this post NASIOC - View Single Post - 2012 STI Stereo Build with OEM NAV H/U, and my experience with professional audio equipment, I recognized the mic connection (pins 5&19 twisted together) as a balanced microphone input (the same signal on both leads, but one is 180 degrees out of phase from the other), possibly a condenser type powered by 5v phantom power (from pin 4. Professional audio usually uses 48v phantom power, but that environment also has to contend with potentially hundreds of feet of signal distance from mic sources; the car doesn't need that). The amplifier mentioned elsewhere in the thread is possibly a preamp that takes the + and - signals from the mic, inverts the - (bringing the main signal into phase with the other lead, but putting the noise 180 degrees out of phase with itself), and combines them together for noise cancellation and amplification (noise component at opposite phases cancels itself out but the same signal component twice in the same phase reinforces itself). Using only one of the mic leads is probably why the previous attempts noted in this thread haven't worked so well: the noise self-cancellation is no longer present, because the other mic lead wasn't included.

 

[HHick123]

EDIT: deleted

 

[HHick123]

EDIT: I deleted my post because I have to re-investigate:
Although the differental (!) audio signal worked with my new android headunit with acceptable quality (!), I got problems with the car battery. Not sure, but maybe it had to do with my circuit (I had no time to analyse it), so I took my circuit out again.

In case, I install it again, or find another solution, I will post my details again.

Regards, Helmut