So I got in a little over my head here thinking I could easily integrate a car audio system and connect my phone (hardwire) to a factory head unit. The cassette player is very charming and I don't want to replace it with a different head unit, and I'm sure many of you understand that. I have a lightly spec'd system with new door speakers and a powered sub. My car doesn't have the factory CD Changer or subwoofer. I've seen the PIE FRD03-AUX unit (which converts an RCA signal to the 16 pin CD changer input), and pending great luck that I found a place online with one in stock, that'll work great (albiet with what looks like a need to attenuate it into the head unit). But I am highly skeptical that they have some old drop shipping spreadsheet they're using and after I order this thing in a couple days they're going to tell me it's out of stock.
So if I can't get a hold of that thing, I saw on a BMW forum someone had another solution that seemed promising.
1. iPhone > JL Audio bluetooth receiver to RCA out (this is spec'd for marine audio, which I suspect is properly attenuated\level matched for aftermarket amplifier levels)
2. RCA out (unknown signal level currently) SPLICED into CD Changer audio wires (currently unknown level)
3. Not sure how I need to terminate the CD changer audio wires, or if at all.
From what I understand, inserting a CD into the head unit disables all input from the CD Changer. And if I take the CD out, but select CD and the changer signals to the head unit that it has a CD (assumed), then it will play from the changer (I know this is the correct behavior, but don't know how the head determines it completely).
This is ideal.
There's only a couple issues I have to unwind.
1. The PIE FRD03-AUX unit, and actually several across different car brands seem to have some complaints over "distortion." This seems to be a level mismatch between the RCA output and 16 pin input on the back of the head, shoddy engineering on PIE's part.
2. I do not know the expected output level of the CD Changer into the 16 pin connector into the head unit (though I can level match this by comparing it to CD output from the head)
3. SOLVED - The head unit does not output levels that the aftermarket amplifier will expect, so JL audio makes a very nice line attenuator for this purpose.
So if I can get anyone in here that either knows, or is willing to measure
A. Audio output level from the CD Changer (that is the two audio wires in the 16 pin connector out of the CD changer into the back of the head unit)
B. What signals the changer is sending to the head unit that may be of concern with this idea
Any help is very much appreciated, I am at the mercy of this shoddily designed part right now and don't want to hack the car up and take away its charm.