How-To Guide: Model 3 SR+ aftermarket to enable speakers and subwoofer upgrade install

PLUR

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Model 3 SR / SR+ owners:

I completed an upgrade to my SR+ sound system. Following from posts before and thanks to users @fstr, @_Travis_ , @Dfwatt, @Flashflooder, @LRonHoyabembe, @Ingineerix and many others in here I was able to do it myself.

Moderator: Please don’t merge this thread. I like to create this How-To thread specific for SR / SR+ car build that has different wiring from premium build, and a specific thread like this for SR for easy visibility and SR to share thoughts and not get confused with the premium build mix.

SR+ speaker system background notes: It is not possible (based on my car setup) for future software updates to activate the side mirror tweeters and rear shelf speakers. I confirmed this in my installation that those speakers are there but the wirings for the speakers did not connect to anything. Also no subwoofer.

Plan: Tap and get signals from the left right door woofer to use for signal of aftermarket subwoofer. Also, tap and get signals from the rear door speakers 4” to get signal for the two door tweeters and two rear shelf speakers. I have never done a sound upgrade for a car before but my dislike for the SR+ sound compelled me to do the upgrade myself (I also didn’t trust outside car stereo shop).

Basically after done, it will power the two tweeters near doors windows and power two rear 4" speakers in back of car, and also adding a subwoofer that will fit in lower area of trunk.

The four main products I'm using are: Pioneer 10" shallow subwoofer, Alpine KTP-445U amp (to power the extra speakers that are inactive now), LC7i, and Pioneer GMD8701 amp
I could have combined the two amps and pick maybe a 5 channels amp instead of two amp but already brought it.
----Update on subwoofer: I find the 12" sealed pioneer to be overpowered for my music listening (non rap/hip hop genre). Consider a smaller sealed sub if you're into vocal/classical music. So far, i'm using 10" and I like it, but maybe even 8" sealed pioneer can be good too. I had to face my sub facing up because it caused too much distortion when facing down in the sub-trunk area. So if your sub sounds terrible with a lot of rumbling/distortion, try placing it in different directions.

Direction:
Please look at this post to find installation guide: fstr post . I’m adding more information below to explain more.

WIRING/POLARITY: Since I couldn’t open up the rear shelf to access the speakers’ polarity, I brought a polarity tester device. This will save you a lot time so you don’t have to open up the doors to find speaker coloring/polarity.

Rear shelf 4” speakers: (Right: Yellow - , Gray +) (Left: White- , Purple +)
Rear door 4” speakers: (driver’s (left) Black -, Red +) (Passenger (right) Blue +, Green -)
Door mirror tweeters: (Passenger (right): Red - , White +) (driver’s (left): Purple - , Black +)
-Caution: remember to turn on your amp high pass filter/add bass blocker when powering tweeters connections
Door woofer: (driver’s (left): Blue -, White +) (Passenger (right): Orange +, Black -)

Tricky part: making connection to wire the right door tweeter. You will know what I mean when you attempt it. My SR+ build in March, left side has extra wiring coming out of the white plastic connector, whereas the right tweeter has no wiring after the white connector. The space in the right was tight that I ended up splicing the wire out of the white connector since there was no space inside to use t-tap (I use a wire stripper in there, strip it out using 18/20g strip, and connect a new wire to it). Also, remember the left driver door mirror tweeter has extra wires coming out after the white connector, you need to cut this existing wires out otherwise you will do some sort of backfeeding to the stock amp (so no t-tap at all for this driver side tweeter, only straight connection to this tweeter and amp).
---Update: @Vector used a PC socket adapter on this passenger tweeter, so this method might be easier for you, read here

Removal of door trim: to access the wiring for the rear door speakers, you need to remove the bottom B panel trim. You need to remove the trims front and back before you can remove the middle B panel trim. The removal should be sequential like this: remove bottom rear seats and side door leather, remove bottom black plastic trim (just pull up), remove black trim near driver seat, and finally remove B pillar black trim by pulling away starting from bottom. I just opened the B panel trim just enough to access wires for signal. Caution: there’s a wire loom that sit on the door trim near the front, don’t try to splice any of this since it has an orange sticker that says attempting to do so might trigger the airbag. Check out this schematic of door trims.

T-tap: The wire gauge for the tweeters and 4” speakers are thin (maybe 20gauge), so t-tap might or might not work. I t-tap several wires but when checking, one connection plastic covering didn’t sheer off the t-tap for there to be a connection. I ended up splicing the wires for these to make sure the connection works. You might or might not experience this. If you don’t want to slice wires, you can also try the posi-tap connector which are more expensive.

Penthouse 12V+ to power amp: A trick I found if you are afraid of shorting the connector when working, you can wait till the penthouse 12v+ is off. Leave all doors & trunk open for some amount of time, after a while you will hear a big clunk near penthouse to indicate the high voltage connector is off. You can check that this 12V penthouse is off by trying to adjust front seats (it won’t move), screen is off, and trunk lighting is off. I tested using a multimeter on the penthouse 12V at this time and it registered no power. I use the same bolt on the 12V+ by taking the lid off the red plastic covering and removing bolt and putting the connection under it and screw it back again.

12V+ Remote in: As noted by user fstr, the 12V+ (aka VCLeft 12v) to supply the amp remote in that Ingineerix video pointed to has a thick red wire attached to it in my car. I believe newer car build might has a red wire attached to this pin. So all you need to do is t-tap into this for power. For my setup (yours can vary), this accessory LCleft 12V+ power the LC7i "12V power", then LC7i "remote out" line powers the alpine "remote in", then the alpine "remote out" powers the subwoofer amp "remote in". My LC7i "remote in" is empty since I have the LC7i jumper setting for GTO on (see pic).

Alpine KTP amp: If you have trouble figuring which wiring configuration works best you can try this. I have the rear doors speakers splits to 4channel(=8wires) > go to LC7i main+ch1 input>LC7i output main+ch1 go to alpine input for front+rear. Set alpine jumper to 4ch and speaker input(non-rca).

LC7i: If you use LC7i leave GTO on as default (see pic). Also this LC7i has AccuBASS which is very useful to increase the low end frequencies that’s needed for the subwoofer.

Grounding terminal: SR+ has a black plastic covering where subwoofer would be in premium. I use the bolt that hold this plastic piece near the right taillight as my ground (-) wiring.

Amplifier: The Pioneer GMD8701 is a refresh 2019 lineup for pioneer amp and it comes with a nice wire remote control for bass. I read certain high power amp might cause the error “cannot maintain vehicle power” but this one so far has not given me any error. If you want to be sure or if u use a big amp, you can add a relay from this thread. I didn't do relay, and I think it has plenty of power for this setup.

Sub Trunk Guide: You can run all the wires to the right side below trunk liner (see video below for trunk removal), and from there use a small knife to cut a cross cut (+) in the sub trunk for all wires to pass into. I do this cut instead of drilling since later on, if the wires are removed, sub trunk fabric fall back into place as if it wasn’t cut out before. This setup, all amp, lc7i, subwoofer are hidden in sub trunk area. Caution: to prevent liquid bottom from dripping into this area and ruin the equipment, be sure you have an all-weather rubber mat on the top or place something in this sub trunk area to prevent accidental liquid from going in.

Helpful videos:
Ingineerix 12V+ accessory video , front door plastic trim removal , rear door removal , trunk removal lining and backseat removal

Materials used: 100ft speaker wires , t-tap connector or positap , 8gauge subwoofer wiring kit or 4 gauge kit

Future work for SR+ sound: The top tweeter speakers near the A pillar aren’t working now. I might attempt to run wires down and power the speakers in parallel to the door mirror tweeters.
--Update on this top A pillar tweeters: I was able to do this by splitting the power going to the mirror tweeters. You can read it here. I would say this add a very slight moderate sound improvement. Read here

That’s all for now. Please share your thoughts, setup, and equipment used.

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PLUR

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#2
Additional pictures:
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LINKS to other sound projects:
---If you want to replace the three stocked 4" speakers in the front dashboard to something better, read here and here
---If you want to replace the two stocked 4" speakers on rear doors, read here (not easy) and also here.
---If you want to activate the top left/right A pillar tweeters, read here.

SIDE PROJECT to Enable Footwell Ambient Light for SR+
---Since you tap the 12V+ driver side power already, use this power to drive the footwell light (Use bolt for ground) for front driver and passenger side. Cut out existing wire attached to the light (don't t-tap).
---For the passenger footwell, run wire through the bottom of center console, see this video or this thread for guide.
 
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Mr. Spacely

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#4
Wow! You have more skill and confidence than most of us. I'm still holding out hope that I can upgrade through a Tesla software offer down the road...
 

Greg Appelt

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Wow! You have more skill and confidence than most of us. I'm still holding out hope that I can upgrade through a Tesla software offer down the road...
I also want some of the features provided in the LR that the SR/SR+ lost out on. Most likely I'll just wait 1-2 years and trade in my SR+ for a LR rather than pull and poke and possibly screw it all up. :)
 

fstr

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Great write-up! Every SR+ owner should do this upgrade. It is very much worth it.
 

PLUR

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#9
An in depth video tutorial aimed at someone doing this for the first time would be amazing. I really want to do this!
If you have the will, you will find a way :)
I'm not good at video tutorial and too busy with work/life tasks. But I'll try to help as much as I can whoever needs.
 
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#10
This is excellent and I fully intend to tackle this at some point in the future. I actually enjoy the stock SR+ sound, but I do miss the additional bass from my subwoofer in the car that I sold to purchase my 3. Thanks so much for putting this guide together
 
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If you have the will, you will find a way :)
I'm not good at video tutorial and too busy with work/life tasks. But I'll try to help as much as I can whoever needs.
Not a problem, appreciate the time you put into your posts. Hopefully taking delivery next month here in the UK, will definitely give this a try! Will be interesting to see what differs on the RHD model.
 

LRonHoyabembe

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#12
My rear door speakers were opposite colors. Passenger (right) was blue and green, driver’s (left) was red and black.

FWIW it might make things more clear if you used passenger/driver side when not speaking about channels specifically. Thanks for the write up though! I’m almost done with my install. Just getting the alpine all hooked up.

P.S. the passenger right channel tweeter was a tough one. I had my wife curled up in the passenger foot well twisting wires while I pulled on the VC_Right harness. Very little room for error there. Ended up using posi twist connectors.
 

PLUR

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#13
My rear door speakers were opposite colors. Passenger (right) was blue and green, driver’s (left) was red and black.

FWIW it might make things more clear if you used passenger/driver side when not speaking about channels specifically. Thanks for the write up though! I’m almost done with my install. Just getting the alpine all hooked up.

P.S. the passenger right channel tweeter was a tough one. I had my wife curled up in the passenger foot well twisting wires while I pulled on the VC_Right harness. Very little room for error there. Ended up using posi twist connectors.
You are right on left/right rears. After reviewing again, I took so many pictures with phone that I mixed it up at the end when I did the write up. I'm updating the thread with your suggestion. Great to hear the positwist works. Thanks.
Mine sharing your setup gears and thoughts on sound outcome?
 

LRonHoyabembe

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You are right on left/right rears. After reviewing again, I took so many pictures with phone that I mixed it up at the end when I did the write up. I'm updating the thread with your suggestion. Great to hear the positwist works. Thanks.
Mine sharing your setup gears and thoughts on sound outcome?
I’m having trouble getting the tweeters to work :( I have the bass blockers on the positive wire heading out of the amp to the tweeters, but I don’t get good audio. I hear a hiss and very faint high pitched transients. I tried with and without the bass blockers. Any ideas?

As for the rear shelf, WOW. You were right — best bang for the buck mod right behind a subwoofer. Improves the sound so much. Feels really full and much less front loaded like before.
 

GDN

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My rear door speakers were opposite colors. Passenger (right) was blue and green, driver’s (left) was red and black.

FWIW it might make things more clear if you used passenger/driver side when not speaking about channels specifically. Thanks for the write up though! I’m almost done with my install. Just getting the alpine all hooked up.

P.S. the passenger right channel tweeter was a tough one. I had my wife curled up in the passenger foot well twisting wires while I pulled on the VC_Right harness. Very little room for error there. Ended up using posi twist connectors.
Interesting if they've changed color wires. I don't really have a horse in this race, but I'm wondering what would happen if everything was described as passenger/driver, then the post just before yours is someone from the UK, they will have a RHD car and perhaps the instructions would no longer work, they would be backwards perhaps.

The computers and things under the dash Tesla simply describes as VC_Left and VC_Right. Here is the question of the day and I don' know the answer, do these computers swap places in a LHD vs RHD car. I'm sure some might know what happened with the S and X, but until we get some RHD 3's on the road I don't know that we would know. I just think using passenger/drivers to describe sides of the car will definitely be limiting and not universal, if everything else in the car remains the same between the two drive versions - LH vs RH.
 

PLUR

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#16
I’m having trouble getting the tweeters to work :( I have the bass blockers on the positive wire heading out of the amp to the tweeters, but I don’t get good audio. I hear a hiss and very faint high pitched transients. I tried with and without the bass blockers. Any ideas?
As for the rear shelf, WOW. You were right — best bang for the buck mod right behind a subwoofer. Improves the sound so much. Feels really full and much less front loaded like before.
Yeah, the rear sounds is best bang...the tweeter is supplemental.
Check that the signal for tweeters is from the 4" midrange. Could be issue with the amp setting/amp gain setting/wiring. Hissing can be amp noise floor. Humming and buzzing are usually something else like ground loop, EMI, RFI.
--Side note: during my initial setup, my tweeters had slight hissing when volume was zero. Didn't know why but when I organized all my wiring in sub trunk area so no extra wires are close the the sub amp, the hissing was gone. Goodluck
 

LRonHoyabembe

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Yeah, the rear sounds is best bang...the tweeter is supplemental.
Check that the signal for tweeters is from the 4" midrange. Could be issue with the amp setting/amp gain setting/wiring. Hissing can be amp noise floor. Humming and buzzing are usually something else like ground loop, EMI, RFI.
--Side note: during my initial setup, my tweeters had slight hissing when volume was zero. Didn't know why but when I organized all my wiring in sub trunk area so no extra wires are close the the sub amp, the hissing was gone. Goodluck
Oh crap... are you driving your tweeters from the rear door speaker audio?

Edit: just re-read. Yes you are. I feel like a dummy. I have front door woofer audio going to the tweeters. No wonder there’s no sound... should be an easy fix though.
 

LRonHoyabembe

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Update: got my tweeters hooked up to the rear door speakers. I think both the tweeters and rear shelf make a HUGE difference. Songs I've listened to 1000 times sound different, and I'm hearing new things in that high freq range. I still need to do some gain adjustments, because it seems like the alpine has much more power than the stock system, but this install was 100% worth it.

My theory is that the car was designed for 12 speakers in their set locations, and when they came out with SR+ they didn’t have any downgraded speaker config produced. So they just decided to turn some speakers off and call it a day. Well, turning off the rear deck created an unbalanced soundstage. The front dash mids are firing upwards to the glass, which then scatters sound towards your head. The back deck does the same, which evens each other out and it feels "full" and immersive. Without the rear deck, you're missing 1/2 of the sound.

it’s like if there were premium headphones, and then the “partial premium” headphones only had the left ear opposed to just cheaper headphones.

Anywho, thanks again for the write up and photos!

Edit: here's my gear list
- Kicker CXA600.1 subwoofer amp
- Pioneer 12" shallow sub (in trunk cubby)
- LC2i LOC for the sub only
- Alpine KTP-445U 4 channel amp powering the inactive tweeters and rear deck speakers
---- Rear door speakers are tapped and output is sent to front input on Alpine amp. "2ch input" setting active. This takes the 2 channel audio from the rear doors and outputs it as 4 channels.
---- 5.6kHz bass blockers in series from amp output to tweeter wiring

Power gear:
- 60A crydom solid state relay
- 100W 4ohm resistor in parallel w/ relay switch
- 4AWG oxygen free copper power & ground
- Remote on signal activates relay and jumps to LC2i. LC2i remote out then turns on the kicker & alpine amps simultaneously.
 
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LRonHoyabembe

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#20
Can I just tap into the the rear passenger door speakers to run the non operational tweeters and rear deck speakers without a amp ?
Not likely. Those rear door speakers are ~40W and that would be splitting the signal 3 ways. You wouldn't get much volume out of that. It's best to use the tiny alpine 4ch amp.