Installed an amp and subs over the weekend

[thesuffering]

Have a 2020 SR (not plus). Since i bought it my only real complaint was the total lack of low end. Figured it would be simple to install a small electrical component in an electric car. ICE vehicles have always been straight forward, and aside from fighting to get the power wire through the firewall they are mostly drama free.

Started reading about the M3 and discovered its by no means just a simple plug and play endeavor.

Not pictured is 12v switched. Im using a solid state relay, Its grabbing 12v constant from the light blue wire in the drivers kick panel for the 12v outlet in the center console, and then its using 12v switched from the center console light. This wire isnt strong enough to run the remote by itself, thus the relay. 12v turns on when the door opens, 12v turns off when you get out of the drivers seat and close the door (basically the behavior you want, on when you are in the car, off when you arent).
Wiring for it i followed from this post: 12v Switched?

So far so good, no error messages whatsoever.

I made up a diagram for the wiring (minus the midbass +/- in the kick panels):

Getting power from the penthouse:

Mocking the amp rack up:

The relay wired up:

Powers on and works. Resistor never gets warm or hot. I do hear the relay thud each time the door is opened, so i am sure it is working.

 

[tegra7]

Nice install. Did you happen to notice at what volume the factory head unit starts to clip?

 

[thesuffering]

Nice install. Did you happen to notice at what volume the factory head unit starts to clip?

2-3 notches below max is clipping according to the LC2i. Its undistorted all the way up to about 90%. I was astonished watching how far i could turn the volume without the maximized light coming on

 

[tegra7]

So 2 or 3 notches from full volume is the safe zone?

 

[thesuffering]

Correct, id probably error on the side of caution to 3 if you wanted to crank it. With the subs in, 70% is already really loud so i never go up to the max. But the signal is mostly clean, kudos to Tesla for that. Now, mind you i didnt hook this up to my oscilloscope and am just going by the maximized light on the LC2i, but it does a pretty good job so I trust it.

 

[tegra7]

One more question. Do you keep your head unit bass volume at zero when setting tour amp gain?

 

[Candleflame]

2-3 notches below max is clipping according to the LC2i. Its undistorted all the way up to about 90%. I was astonished watching how far i could turn the volume without the maximized light coming on

interesting..... so do they pseudoincrease loudness for the last 3 clicks on volume with a clipper/brickwalllimiter? so loudest clean sound is at 85% volume?

 

[bo3bdar]

This is awesome, thanks for the writeup. I've also got an SR (no plus) unicorn, and am currently doing my wiring for an improved stereo.

I go back and forth on needing to use a relay, because I'm going to use a JBL DSP4086 which can be configured to power up only after it sees a signal. I think I'll start with that, and see if I get any errors thrown by the car.

For what it's worth, I studied all the possible power connections for the car, because there are a lot of conflicting opinions. My opinion is that you don't want to mess around with the front 12V battery, it's already a weak spot for the car. I think the penthouse is the correct spot to draw power as long as you can avoid inrush current errors. (my writeup here)


The stereo in the SR is actually quite good, I've profiled it using REW software and Umik microphone. One curious thing was that while I stalled out on my install, a Tesla update actually improved the audio. Someone at Tesla actually tweaked the built in EQ to improve the audio.

As OP notes though, the bass is really missing on SR or SR+ though, with no subwoofer. It's OK, but easily the weakest part of the audio quality now.

 

[Candleflame]

This is awesome, thanks for the writeup. I've also got an SR (no plus) unicorn, and am currently doing my wiring for an improved stereo.

I go back and forth on needing to use a relay, because I'm going to use a JBL DSP4086 which can be configured to power up only after it sees a signal. I think I'll start with that, and see if I get any errors thrown by the car.

For what it's worth, I studied all the possible power connections for the car, because there are a lot of conflicting opinions. My opinion is that you don't want to mess around with the front 12V battery, it's already a weak spot for the car. I think the penthouse is the correct spot to draw power as long as you can avoid inrush current errors. (my writeup here)


The stereo in the SR is actually quite good, I've profiled it using REW software and Umik microphone. One curious thing was that while I stalled out on my install, a Tesla update actually improved the audio. Someone at Tesla actually tweaked the built in EQ to improve the audio.

As OP notes though, the bass is really missing on SR or SR+ though, with no subwoofer. It's OK, but easily the weakest part of the audio quality now.

what update are you talking about? there was an update in either 2020 or 2021 (cant remember now) which distinctivly changed the way the soundsystem sounded

 

[thesuffering]

One more question. Do you keep your head unit bass volume at zero when setting tour amp gain?

Eq was flat when i set the gain if thats what you meant, then used the multimeter then to get desired wattage output from the amp to not blow the subs.

 

[thesuffering]

interesting..... so do they pseudoincrease loudness for the last 3 clicks on volume with a clipper/brickwalllimiter? so loudest clean sound is at 85% volume?

According to the LC2i, yes.

I go back and forth on needing to use a relay, because I'm going to use a JBL DSP4086 which can be configured to power up only after it sees a signal. I think I'll start with that, and see if I get any errors thrown by the car.

I paid for a consultation with Matt Schaefer of Sound Fx/Musiac Design prior to this install, because as you point out there is a ton of information floating out there. Hes done quite a few Tesla installs and has been featured on many major audio brands websites (such as Focal). He said unfortunately signal sense will not work for the Tesla due to Sentry. There is enough going on with the speakers that it kicks the signal sense on when it shouldnt be so the system will be on when you arent in it.

Additionally, its the amp getting fully depleted (when the penthouse shuts down) that is going to throw an error due to in rush current and the reason for the big relay/resistor. The resistor allows the amp to get a trickle of power to charge up the caps while the system comes online, the remote wire flips the relay and the big power wire completes its circuit and full power is introduced. Because the caps were charged already via the resistor, no in rush current happens, and the car is happy and believes nothing is amiss. Even if signal sense did work, it would only eliminate the front relay. You still need the big relay and resistor to avoid errors. All in, it was maybe $100-150 in parts total and now I have peace of mind.

Edit- wanted to add i read your write up. Matt did actually suggest using an aux battery setup was his preferred way to install. He said you would hook it up to the penthouse in parallel to keep it charged and then all your 12v aftermarket stuff hooks up to the battery. The Tesla never knows about it. An aux battery is in the ~$200 range so its a compelling argument. But im also cheap, so saving money using the relay sounded better. His secondary suggestion was the relay/resistor/penthouse setup and hes done it in plenty of cars without any problems so far.

 

[bo3bdar]

what update are you talking about? there was an update in either 2020 or 2021 (cant remember now) which distinctivly changed the way the soundsystem sounded

I'm sorry, I didn't track which version changed this. There was no note of it in release notes, I just noticed the audio was better at some point. I've got some older Umik test results that I'll see if I can narrow it down. I'll do a new profile and compare to my old results.

I paid for a consultation with Matt Schaefer of Sound Fx/Musiac Design prior to this install, because as you point out there is a ton of information floating out there. Hes done quite a few Tesla installs and has been featured on many major audio brands websites (such as Focal). He said unfortunately signal sense will not work for the Tesla due to Sentry. There is enough going on with the speakers that it kicks the signal sense on when it shouldnt be so the system will be on when you arent in it.

Additionally, its the amp getting fully depleted (when the penthouse shuts down) that is going to throw an error due to in rush current and the reason for the big relay/resistor. The resistor allows the amp to get a trickle of power to charge up the caps while the system comes online, the remote wire flips the relay and the big power wire completes its circuit and full power is introduced. Because the caps were charged already via the resistor, no in rush current happens, and the car is happy and believes nothing is amiss. Even if signal sense did work, it would only eliminate the front relay. You still need the big relay and resistor to avoid errors. All in, it was maybe $100-150 in parts total and now I have peace of mind.

Edit- wanted to add i read your write up. Matt did actually suggest using an aux battery setup was his preferred way to install. He said you would hook it up to the penthouse in parallel to keep it charged and then all your 12v aftermarket stuff hooks up to the battery. The Tesla never knows about it. An aux battery is in the ~$200 range so its a compelling argument. But im also cheap, so saving money using the relay sounded better. His secondary suggestion was the relay/resistor/penthouse setup and hes done it in plenty of cars without any problems so far.

Yowza, super interesting and thanks for the info from Matt. There is a lot of hard to decipher info on the internet, and I put much more weight on people who have actually done the work and understand gritty details. I'm an EE, so I've got great background understanding, but not much car install experience. And almost no one has actual Model 3 experience.

I'm also trying to keep my install simpler and cheaper, which is a big motivation to avoid the relays. That one example of setting the car on fire demonstrates this needs to be more carefully designed. However, I think you are on the right track with the dual relays and the potentially bad fire-starter resistor is switched out when up. I also see you have a fuse at the penthouse connector (not on your schematic), which is the right idea. I'm going to undersize that fuse, because I don't think I'll ever remotely come close to needing full power with my dual amp design.


Given Matt's opinion, I'll have to rethink my plan here. I'm not actually concerned about the stereo being on during Sentry or charging, the actual draw with zero signal is not going to turn the dial on car range, although I of course will measure idle draw power.

I think it's hard to get the answer from thousands of posts, but my reading especially from Travis' experience strongly points that the inrush problem is actually because the car is more sensitive when it throws the contactors at wake, because it's looking for faults/shorts at power on. Once the car is hot, it doesn't appear to matter that the amp has an inrush current, because that is similar to turning on the AC or other giant loads. And once the car is hot, the penthouse can provide 200A without complaint.

 

[thesuffering]

I'm also trying to keep my install simpler and cheaper, which is a big motivation to avoid the relays. That one example of setting the car on fire demonstrates this needs to be more carefully designed. However, I think you are on the right track with the dual relays and the potentially bad fire-starter resistor is switched out when up. I also see you have a fuse at the penthouse connector (not on your schematic), which is the right idea. I'm going to undersize that fuse, because I don't think I'll ever remotely come close to needing full power with my dual amp design.

Yea, I have a 125 amp fuse on the penthouse within < 12 inches. No way id allow that much power unfused. Thats just asking for a fire if something shorts. Its also using 4ga OFC from KnuKonceptz and its 450w amp which only has 40 amps worth of fuses on it. The cables are overkill for my system, but they also shouldnt melt or get hot.

Additionally I have a 2 amp fuse on the remote wire coming from the front relay, and a 5 amp fuse before the resistor. I figure the more spots that are fused, the better.

 

[RichardV]

Etd

 

[bo3bdar]

Yea, I have a 125 amp fuse on the penthouse within < 12 inches. No way id allow that much power unfused. Thats just asking for a fire if something shorts. Its also using 4ga OFC from KnuKonceptz and its 450w amp which only has 40 amps worth of fuses on it. The cables are overkill for my system, but they also shouldnt melt or get hot.

Additionally I have a 2 amp fuse on the remote wire coming from the front relay, and a 5 amp fuse before the resistor. I figure the more spots that are fused, the better.

With your amp at 450W, and the LCS should be nominal power, that 125A fuse seems high to me, 450W/12 is 38A, so I'd use a lot smaller a fuse there. The amp itself looks to have dual 20A fuses. But I'd defer to Matt if he recommended it.

On my build, I currently have that specced to an 80A fuse for two amps, a JBL DSP4086 (40A fuse) and JL Audio MX600/3 (50A fuse). Combined these are about 900W, but of course I'd never likely hit that sort of level, no point in blowing out my ears. This is the part where my lack of experience in car audio may surprise me later, but if I wind up blowing fuses a lot, I can revisit it. I like to start conservatively.

Wiring wise, I'm using 8G OFC, because this is a really short run from the penthouse to the back right corner for the amp mounts. 4G is recommended for the JL Audio, but for this short run and Class D amps it will be fine, and it's what I've got on hand. (On the other hand, it'd be nice to have a single power wire instead of two from penthouse area.)

How to calculate the best wire gauge for your car amplifier

How to determine the best size wire for your amp's power and ground

www.crutchfield.com

Question: where did you attach your ground?

I've seen a couple of different suggestions, and currently I'm planning to use the mount point in the right corner near the amp board I'm going to attach to the plastic shield. Same ground point used by the LR premium audio amp.

Question: do you have any concerns about airflow being in the closed sub-basement?

Question: how does it sound? Meet what you were looking for?

 

[thesuffering]

With your amp at 450W, and the LCS should be nominal power, that 125A fuse seems high to me, 450W/12 is 38A, so I'd use a lot smaller a fuse there. The amp itself looks to have dual 20A fuses. But I'd defer to Matt if he recommended it.

On my build, I currently have that specced to an 80A fuse for two amps, a JBL DSP4086 (40A fuse) and JL Audio MX600/3 (50A fuse). Combined these are about 900W, but of course I'd never likely hit that sort of level, no point in blowing out my ears. This is the part where my lack of experience in car audio may surprise me later, but if I wind up blowing fuses a lot, I can revisit it. I like to start conservatively.

Wiring wise, I'm using 8G OFC, because this is a really short run from the penthouse to the back right corner for the amp mounts. 4G is recommended for the JL Audio, but for this short run and Class D amps it will be fine, and it's what I've got on hand. (On the other hand, it'd be nice to have a single power wire instead of two from penthouse area.)

How to calculate the best wire gauge for your car amplifier

How to determine the best size wire for your amp's power and ground

www.crutchfield.com

Question: where did you attach your ground?

I've seen a couple of different suggestions, and currently I'm planning to use the mount point in the right corner near the amp board I'm going to attach to the plastic shield. Same ground point used by the LR premium audio amp.

Question: do you have any concerns about airflow being in the closed sub-basement?

Question: how does it sound? Meet what you were looking for?

Good point about the fuse. Its what the kit from KnuKonceptz included, but im not using anywhere close to that much power so it'd likely be safer to downsize the fuse. The amp does has dual 20A fuses, so throwing a 40-50 amp fuse in the place of the 125 is fine.

To answer your questions:
where did you attach your ground?
Im using the exact ground point you are talking about for the premium system amp in the passenger rear corner. I had seen some suggestions to ground near the penthouse, but you should ground as near as possible. I figure if the spot is good enough for Tesla, its probably fine for us. It was a really easy run from the subtrunk.

do you have any concerns about airflow being in the closed sub-basement?
I have somewhat, but its pretty open in there and i doubt its getting overly hot. I have thought about maybe adding a couple 12v computer fans if it becomes a problem. Im not overloading the system, running it at 2ohms so the amp never really gets hot. Im in Arizona, and we are starting to see triple digits, so we'll find out if heat becomes an issue at all. So far, any time i have opened the subtrunk the components are warm at worst and the ambient temperature of the subtrunk isnt anything noticeable at all.

how does it sound? Meet what you were looking for?
In a word, incredible. It really has made a world of difference. It can get overwhelmingly loud if i want to push it, but importantly it fills out the low end at all volume ranges and really delivers what was missing. I had this same system in a 2017 Jeep Cherokee before this, and it definitely sounds louder in the Tesla, and the compliment of an actually decent OEM system rounds it all out. Its one of the best sounding car audio systems ive had

Im current considering the NVX Boost Box. Itd be really nice to have the most of the entirety of my trunk useable, and its a 500w rms sub vs the 150w each from the Kickers. But then i think about it and would have less cone space, and the current box is actually fairly thin anyway. I wonder if it would actually be a downgrade to go the NVX route. Being able to make a fiberglass box is one skill I wish i learned, itd be nice to be able to diy something.

 

[Zangief1977]

Do you think you could have gotten away with using the Stinger 80 amp relay instead of the 200amp one?

 

[thesuffering]

Do you think you could have gotten away with using the Stinger 80 amp relay instead of the 200amp one?

If i remember right, in my research leading up to this i read a thread where a member had mentioned 80 amp didnt work for them and it threw an error. FWIW i have not had a single issue in the 3.5 months since installing this. I know the 200 amp one is expensive, but IMO buy once cry once, instead of trying a cheaper one and it not working and having to buy the more expensive one anyway.

 

[thesuffering]

Recently had some ask for the diagram including the lc2i pro in the mix so ill share it here as well. Changed color coding for remote/12v switched wires to avoid confusion

 

[Zangief1977]

Hi I'm having a hard time finding the brown wire for switched 12v. Did you splice into the blue diagnostic connector below the rear air vents to find the brown wire?