Integrating Harman Kardon speaker into car

Thread Starter

burningskies202

Joined Jan 28, 2020
3
Hey guys i picked up one of those nice Harman Kardon Onyx Bluetooth speakers from my local thrift shop the other day and the sound quality is superb! anyway, i was thinking i would like to integrate it into my old Mazda 121 as the stock speakers are pretty terrible. I'm just having trouble figuring out how i should merge it into the car audio ecosystem.

The car currently has a small BlueTooth stereo that drives 4 small speakers. i would like the main head unit in the car to still drive the front speakers but have the back speakers replaced with the Harmen Karmon Amp.. somehow..
any ideas??
 

Thread Starter

burningskies202

Joined Jan 28, 2020
3
So I've done some looking around inside the speaker and now I'm looking for an injection point to feed audio from the RCA OUTPUT in the back of the car's head unit. I have isolated the LEFT and RIGHT INPUT channels on the TPA3116 Audio drives and have traced them back to the DAC's analog outputs .
Where would be the most logical place to inject the audio into the system? I know little about the DAC itself. do I inject before or after the DAC?
ThanksAudio pic.jpg
 

Audioguru again

Joined Oct 21, 2019
2,091
You must disconnect the DACs to feed in your attenuated external audio signals. The Harman Kardon speaker uses a 19V power supply. Where will you find 19V in your car?
 

Thread Starter

burningskies202

Joined Jan 28, 2020
3
So i cant just inject after the DACs? so i have to cut the traces and inject the audio into the first line of capacitors after the DAC?

also, i have a few adjustable boost converters laying around that will do the trick when it comes to powering the device.
 

Audioguru again

Joined Oct 21, 2019
2,091
The DAC has audio signal outputs. Your car radio audio signals are also outputs that might need attenuation. You should never connect outputs together because one of them (probably the DAC) will be destroyed.

The 19V might need voltage regulation and draw a current of 5A. The voltage boost converter might turn off between high current parts of music then you will hear when it turns on again.
 
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