Posts: 23
Joined: Mon Aug 31, 2020 7:52 pm

Need to upgrade sound

Sat Dec 19, 2020 5:09 pm

This is the first vehicle I've considered upgrading the sound system since my 20's (spent 5k back then). I don't have the HK upgrade but have every other option. I figured any standard system is fine for me now, but was I wrong.

It's worse in the back seat. Are there no speakers back there? Amy wife HATES spending money on car accessories but she is practically begging me to upgrade the speakers. She says she can't hear anything back there.

We don't need 12" subwoofers or anything. What is the best way to improve the sound from the back seat? When playing movies on the car screen on longer trips we have the volume turned up all the way up they still can't hear what actors are saying in certain scenes.

Has anyone installed extra speakers in the back? What is all involved in that installation? Would just upgrading the door speakers with multi-directional speakers work? I don't want to spend a lot of money on this. We're not looking for super high quality sound. Mostly just want to be able hear vocals. My wife says she feels like she's listening from another room with the door shut.

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Joined: Sat Nov 01, 2014 7:36 pm
Location: Honolulu, HI

Re: Need to upgrade sound

Sat Dec 19, 2020 7:13 pm

The base entertainment system includes 4 speakers, all up front, so there's no sound, climate control, windows that open, etc., for back seat passengers.

The i3 is basically a 2-door car with enhanced back seat access that is more suitable as a cargo carrier with the back seats folded down.

2014 BMW i3 Arravani Grey, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, JuiceBox EVSE

Posts: 76
Joined: Thu Oct 10, 2019 7:31 pm

Re: Need to upgrade sound

Mon Dec 21, 2020 9:32 am

Honestly, the best option is probably to hit up a local custom stereo store and have them upgrade you. They can wire in an amp and rear speakers no problem. While you are at it, there are aftermarket options to add Android Auto/Apple Carplay (something I added to my old Grand Cherokee that I miss in the i3). I know, paying someone ups the cost a bit, but at least around here the cost isn't terrible and they do a good professional job. Unless you are really strapped for cash, just pay the $100 or whatever for someone who does this all day every day.

I have the HK audio system in mine because I knew I wouldn't be happy with the base audio, and even that isn't all that great. I may end up adding a subwoofer and Android Auto (the other speakers are decently mediocre but good enough for me). Then again, my wife has decided the i3 is hers and she likes to keep her vehicles 100% stock.

Posts: 16
Joined: Tue Dec 15, 2020 9:50 am

Re: Need to upgrade sound

Fri Dec 25, 2020 9:40 am

I would recommend you visit bimmertech - for :
1. speaker only upgrade
2. or amp/ speaker upgrade
3. or apple carplay/ android upgrade + amp

Mine have the premium HK sound system but still not as good as my CRV after market head unit upgrade.
But i'm contented with it for now.

Posts: 136
Joined: Tue Dec 22, 2020 6:06 am

Re: Need to upgrade base sound

Mon Dec 28, 2020 5:01 pm

There might be another way:
The base Audio is decent - just not all around. Wanted to start a thread to collect and share information about an upgrade:

Please add and correct my assumptions:

1. There are 3 screw speaker mounts in the rear doors behind a plastic cover and foam.
2. The speakers from the front and other BMW/Mini models should fit in these mounts
3. No Cable for the speaker in the rear door
4. The Head-unit has 4 Speaker! outputs
5. The NBT(evo) Head-Unit is the same as in a other BMWs which have speakers in the Rear (the pinout suggests it's there)
6. The Tone menu does not show the Fader - Front Rear balance

Does anybody know if the BMW drives the front 4 speakers in the i3 with all the 4 outputs of the HU? Or do they use a passive Hi/Low Pass?

The Idea I have:

Installing two BMW speaker (regular or HK) from the Junkyard for a few bucks (many models after 2004 have the 3 screw speaker)
(got two 7 Series speaker with tweeter for all of $11 from my local yard)

Snaking wires into the doors.

Taping into the rear speaker wire of the HU and see if they work. If not

- is adding a small high level input amplifier underneath the rear seats and powering the the speakers from that one.


According to the Database 96: AUDIO_SYSTEM offers following options:

Stereo, HiFi, TopHifi, hk_surroundsound, - the i3 is standard set to "Stereo"

The information about Hifi is the "basic 6 speaker configuration" - 4 in the front and 2 in the back. So that would be basically what we are looking for.

While TopHifi is looking for another amplifier - The Top Logic 7 AMP amplifier.

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Joined: Sat Jan 02, 2021 1:38 pm

Re: Need to upgrade sound

Sat Jan 02, 2021 1:54 pm

I’m being in same project, so I’m following your posts. ;)
That I already know, all 4 speaker out are wired in HU. All four wires go to front 4 speakers,
According internet kick speaker low band, door speaker mid&high and both band filtered in HU!

Today I measured the resistance on HU connector:
1-5 - 4 Ohm
2-6 - 6 Ohm
3-7 - 6 Ohm
4-8 - 4 Ohm

So, keep going. :) I hope we will solve this. ;)
Last edited by csg78 on Sun Jan 03, 2021 4:42 am, edited 1 time in total.

Posts: 85
Joined: Sun Jul 09, 2017 11:07 am

Re: Need to upgrade sound

Sun Jan 03, 2021 4:22 am

Protonic, I just resurrected an old thread on the technical chat. Just don't let your wife see it! :lol:

2015 i3 REx, 60ah, solar orange. Reversing camera, leather interior, sunroof, park assist, professional navigation.

Posts: 136
Joined: Tue Dec 22, 2020 6:06 am

Re: Need to upgrade sound

Sun Jan 03, 2021 5:16 am

This is how the i3 is wired then?

This is from other BMWs

Got the picture from link from ... ing-cable/

Putting it all together:

Rear Right 1-5 - 4 Ohm - Subwoofer Right (kick panel)
Front Right 2-6 - 6 Ohm - Mid Range Right
Front Left 3-7 - 6 Ohm - Mid Range Left
Rear Left 4-8 - 4 Ohm - Subwoofer Left (kick panel)

So, that is good information.

Wondering where the 6 ohms are coming from. BMW usually has 2 4 and 8 ohm speakers. Special configuration for the i3?

If we would put those in parallel with front Right and Left - 4 + 6ohm = 2.4 ohm
4+4 ohm = 2 ohm in parallel.

Which is kinda low. Bot not terrible - BMW drives parallel speakers in the 3 series of the head-unit or uses 2 ohm speaker in other models.


I just measured the speakers which I got from the 7series Those have 4 ohms on the label but when I measure them with my multimeter they are showing 2... need a better multimeter :P

Trying the speaker in parallel with the front speakers and see what happens.

Posts: 4
Joined: Sat Jan 02, 2021 1:38 pm

Re: Need to upgrade sound

Sun Jan 03, 2021 5:30 am

The question is: is there a built in band pass in HU or speakers have? Full band comes out from HU or already filtered?

edited: if 2 Ohms no problem then that is not a question. :)

Posts: 136
Joined: Tue Dec 22, 2020 6:06 am

Re: Need to upgrade sound

Sun Jan 03, 2021 8:09 am

at least the signal to the woofers is filtered.
Just put the speakers I got from the junkyard in parallel to the front speakers - the resistance stayed at 5-6ohm according to my multimeter.

Which is weird - it should have dropped - or the headunit adjusted for it?

BUT it works - got nice sound with the speakers sitting on the floor in the back. :) getting some pictures.

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