Audio Question

[javis20]

Ok, first of all please don't suggest expensive upgrades like Bav, it's not what I'm interested in.

Now, down to business. My sons 2003 Z4 E85 has the super duper 10 speaker premium hifi DSP 10 speaker system. However, the previous owner replaced the head unit with an aftermarket unit. Since that didn't work with the original amplifier, he replace that with a Rockford Fosgate R600x5. A 5 channel power amp. Basically it has front left and right, rear left and right and sub outputs. I'm not 100% sure which way the PO wired the system, but it's not right at all. The tweeters are being over driven with mid range frequencies and the door mids don't seen to be working at all. The factory tweeters do not have a high pass filter builtin, so I suspect he is blasting them with a full range frequency signal.

My rewiring thoughts are as follow;
1. Install hi pass filters/caps on the front tweeters to block low and mid frequencies.
2. Wire 3 front right speakers in parallel on one channel. Kick panel speaker, door mid range and tweeter.
3. Wire 3 front left speakers in parallel on a 2nd channel. Kick panel speaker, door mid range and tweeter.
4. Wire right rear mid range and woofer in parallel on the 3rd channel..
5. Wire left rear mid range and woofer in parallel on the 4th channel

Thoughts? Has it been tried before?

 

[Anonymous]

Hi I don’t know the E85 well but the BMW sound systems are relatively common across model ranges...

Seems like the amp can generate a sub woofer output from the inputs?

Does the head unit have a separate sub woofer feed?

I assume the head unit has 4 channels out?

Your plan works but maybe use the subwoofer amp section to drive the rear subwoofers since it’s available..

Without DSP the sound will always be ‘off’ due to inability to selectively equalise each channel..

Actually wiring all 3 in a parallel without a crossover may drag the impedance down too low for those channels..

As suggested elsewhere a crossover with some degree of adjustment would be better if you were going down that route on each channel..

 

[Darkangelv2]

You could purchase 2 pairs of crossovers - a 3 way and a 2 way and just wire them inline?

 

[javis20]

Good suggestions. I already ordered a 2nd order high pass filter for the tweeter. If there are issued I'll buy a pair of three ways. Using the sub output for the rear woofers is a good Idea, I'll give it a try. Concerning the impedance for the three fronts in parallel. The amp is rated for very low impedance loads.

 

[Anonymous]

The BMW speakers normally 4 ohm,,the unit looks good and robust but 4/3 = 1.33 ohm so a bit low even for a 2 ohm minimum amp..your call!

With a 3 way crossover gets round that nicely...espcially if its tailor-able repsonse..

 

[javis20]

Yes, I know. I'm counting on the combined impedance being closer to 2 ohms below 5khz, because of the high pass filter.

 

[Anonymous]

Yes, I know. I'm counting on the combined impedance being closer to 2 ohms below 5khz, because of the high pass filter.

Sure as we say in aviation i said it for "the benefit of the tape" so if it goes wrong its not my issue..

 

[javis20]

Completed the modification. I just add a 5.6 mf capacitor in series with the tweeter. Huge improvement, at least as much as possible with the current amp.