Need Audio Help Please

[E82_MDubb]

Hi All,

I apologize first if this has been covered, I read a lot of threads, but cannot confirm what works and what doesn't, so please help, thanks.

Car: 2011 135i, with base stereo, no tweeters, just 4 mids with 2 subs.

I am looking to upgrade to:

676 HU that I purchased for $40.
Question 1: will I need to program anything since my car is base model stereo?

Logic 7 speakers: 2 front tweeters, 2 front mids, 2 rear mids, and maybe 2 rear tweeters, and 2 subs.
Question 2: will the technic wiring harness designed for the 676 hifi stereo work to add aftermarket amps to push the logic 7 speakers?
Question 3: I have read that logic 7 speakers are 4 ohms, and the subs are 2 ohms, does that mean that if I connect the tweeters and mids in parallel to the amp, it is at 2 ohms? I guess the question is whether 4 ohms is at the speaker level, and not as it is connected from the factory, which I understand is parallel.

I am thinking of driving the 4 fronts (2 tweeters + 2 mids) and 4 rears (same as front) in parallel with a 4 channel amp, and the 2 subs wired in series for 4 ohms (2 subs at 2 ohms each, wired in parallel to give you 4 ohms) and drive it with a mono amp.

Question 4: I noticed the factory front mids have tiny magnets, while the rears have much larger magnets, and was wondering if it's possible to install the rears in the front? I figured it may sound better?

Thanks in advance for any help I can get!

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Originally Posted by E82_MDubb

I am thinking of driving the 4 fronts (2 tweeters + 2 mids) and 4 rears (same as front) in parallel with a 4 channel amp, and the 2 subs wired in series for 4 ohms (2 subs at 2 ohms each, wired in parallel to give you 4 ohms) and drive it with a mono amp.

Usually each channel from a 4 channel amp goes to a corner of the car. And some sort of crossover divvies the sound between the mid and tweeter at that corner. There are a million ways to do that. I think the HK system just has a capacitor on the tweeter and is that all? If you mean a mid and tweet get run in parallel to a single amp output then I think you're right.

Not sure if the underseat "subs" are normally in parallel or if each gets its own signal left / right. But FYI if you run a pair of 2 ohm speakers in series you get 4 ohms, if you run them in parallel you get 1 ohm.

Originally Posted by E82_MDubb

Question 4: I noticed the factory front mids have tiny magnets, while the rears have much larger magnets, and was wondering if it's possible to install the rears in the front? I figured it may sound better?

Possibly for clearance, i.e. not crash the window into them? Even if it clears going up and down it could hit when it's down and you close the door. I have no idea on this but if you try it out keep an eye on the window glass. And, generally speaking, if the factory designated them for different spots there was probably a reason.