My 2009 e89 came with the standard radio driving 6 speakers: a 10 cm midrange speaker in each door, 10 cm midrange speakers in the rear shoulder panels, and 6 1/2" mid-woofers in the kick panels. The sound quality was not great, but I was stuck using the OEM head unit as it was integrated with the iDrive navigation system, so I started on a quest to improve the sound quality by upgrading the rest of the system.
With the head unit powering only the speakers in the doors, it suddenly had more than enough power to drive those speakers to insane levels. I ended up setting the gain on the JR Audio amplifier to approximately half to match the sound level of the door speakers. The front/rear fader, left/right fader and tone controls all work as they should. The system now has shimmering highs; clear, clean midrange; and powerful, tight bass. The overall sound is phenomenal, is light years better than the OEM DSP system I had in my e85, and friends who've ridden with me have all commented about the quality of the sound system.
- I began by replacing the single door speakers with Emphaser 2-way component system speakers (http://www.emphaser.com/products/upgrade-systems-for-bmw/em-bmw3fr1/?lang=en). They were a simple plug and play installation, the midrange sound was much clearer, and adding the separate tweeter made a HUGE difference.
- Next I replaced the rear shoulder panel speakers with Emphaser coaxial speakers (http://www.emphaser.com/products/upgrade-systems-for-bmw/em-bmw3fr2/?lang=en). Again installation was straightforward plug and play. Although the sound improvement was noticeable, the head unit struggled powering these to sufficient sound levels.
- I then replaced the 6.5" mid woofers with two 1 ohm 6.75" Kicker subwoofers that I wired in series to create a 2 ohm load (https://www.kicker.com/comp-rt-6-75-1-ohm-subwoofer). Although I needed to drill new holes to attach the speakers, they otherwise fit perfectly. The head unit was incapable of powering these, and as I wasn't getting sufficient sound from the rear speakers . . .
- I installed a JR Audio three channel amplifier (https://www.jlaudio.com/collections/car-audio-amplifiers/products/xd500-3v2-car-audio-xdv2-amplifiers-98603), which I attached to the rear bulkhead. I extended the speaker leads from the mid-woofer speakers in the kick panel and plugged them into the high-level input of the subwoofer channel, extended the speaker leads from the rear shoulder-level speakers and plugged them into the high-level input for the stereo channels, and ran new speaker wire from the amplifier to the subwoofers and coaxial rear speakers.
With the head unit powering only the speakers in the doors, it suddenly had more than enough power to drive those speakers to insane levels. I ended up setting the gain on the JR Audio amplifier to approximately half to match the sound level of the door speakers. The front/rear fader, left/right fader and tone controls all work as they should. The system now has shimmering highs; clear, clean midrange; and powerful, tight bass. The overall sound is phenomenal, is light years better than the OEM DSP system I had in my e85, and friends who've ridden with me have all commented about the quality of the sound system.