I'd like a sanity check on my assumptions before I upgrade my front speakers. I have a 2007 MC with the hifi upgrade. I plan to use 2-way components and disconnect the 3.5" OEM speakers. I am leaving the hifi amp in place for now thanks to BMW's insistence on needing it in order to upgrade the car's software.

1. The OEM amp contains a crossover that affects the signal received by the 5.25" and 3.5" speakers. We don't know what those crossover points are.

2. #1 means that I'd be better off not using aftermarket crossovers. I should let the OEM amp's internal crossover do its thing and retain the tweeters' inline high pass filters.

3. I can wire up the components using the speaker wires that previously fed the 5.25" and tweeters. However, the amp's crossover still assumes the presence of the 3.5". So I might I get some odd frequency response from my new 2-ways.

 

It is my impression that mostly bass is going to the 5.25 speaker location. The tweeters in a two way speaker may not get much signal. You should test it before you commit.

Someone said the system uses filters rather than crossovers. I'm not sure.

I think if you eliminate the 3.5" you will be eliminating a lot of mid-range and high frequencies.

What speakers are you using?

I used 6-1/2" component speakers for the 5.25" location. That gave me a separate tweeter to use elswhere.

I used 4" two ways in the 3.5" location.

 

all the answers are in teh speaker replacement sticky.

try getting 3way components to upgrade the HiFi. you'll be much better off.

 

Sorry, I meant 2-piece components. I'm not using coaxial speakers. Robin, did you have any fit issues with the 4" speakers? 3.5" seems to be an odd size in the market.

I haven't bought the speakers yet - just wanted to confirm everything I got out of the sticky and a few other threads in this forum.

 

I first bought Infinity Kappa 3.5" and they were way too small. The 4" fit fine. Some drilling required to match the hole pattern, but that would probably be true of any speaker the OEM hole pattern is odd. The OEM speaker does actually measure 4". I don't know where the OP got the 3.5" measurement. There is no marking on the speaker indicating its size.

On the 6.5" Infinity Kappas I had to use a plastic ring that came with the speaker to protect the speaker in shipment. This was a clear vacuformed ring that snaps onto the speaker and protects the rubber that connects the cone to the rim. Without this piece, the foam seal on the OEM grille would crush the rubber -- inhibiting the speaker' cone movement. Works fine with the speaker in place and does provide the seal that the foam was intended for. Otherwise, I'd have to rip the foam off.

 

Robin,
So are you saying that you end up using the shipping "ring" from the 6.5" as a spacer, to space the speaker away from the foam seal? OR, is the "ring" being used to match the mounting hole pattern better?

Thanks.