Gen 5 Prime XSE Premium - Adding a powered subwoofer to the JBL system and need advice

Leftmost connector. Bottom row. Starting from the right.

Violet - Ignore
White - Left Rear -
Black - Left Rear +
White - Right Rear -
Black - Right Rear +
Yellow - Ignore

That should be what you need.

 

Was there room for this and do you have photos? where did you get power for amp, etc?

 

You want to tap the front doors, they're are the only ones that get a full signal. The rear doors do not get much if any bass signal. I used a jumper harness so I didn't have to cut the factory wiring.

 

Do you by chance have a link for the jumper harness you used? Is the jumper harness long to reach all the way to the back or is the subwoofer's cable long enough to reach the back from the jbl amp jumper harness under drivers seat?

 

I bought one from here but I had to re-pin it since the default configuration was incorrect. This goes under the seat, you just unplug the cable from the amp, add the harness and splice as needed.

30-pin Subaru Harman Kardon and/or Toyota JBL Amp jumper - Splice Harness to add Subwoofer

 

This notion got me curious. Have you always noticed that your system was front speakers biased?

I was driving and listening to '23 Prime XSE Premium with the JBL for 4 months, and it was very well balanced, with most of the bass coming from both the Fronts and the Rears. In fact, going to JBL's website would correlate this.

Now the only speakers that would be present are on the front doors, while the rest seem like they've been turned down to 10%

Just curious if that's what's causing most to want to add a subwoofer. This system according to the manufacturer was supposed to be 800 WATTS!

 

The front doors are doing most of the work. The rears sound like they have a high pass crossover and a db cut. The system as stock has pretty good mid-range punch but lacks low bass < 100hz. That 800w total peak rating is just fluff, I would guess its really 5-15w RMS per channel tops.

 

Toyota seems to do the weak rears across a lot of their vehicles, even the 5th Gen Prius.

Park your car.

Open your front door and your rear door.

In your head unit under sound tuning move the dot to the front so that sound is nearly exclusively coming from the front speakers.

Listen to the front door audio. Feel how the bass kicks. Listen to how loud it is.

Now back to the head unit and move the dot to the rear.

Go listen to the rear door speaker. Loudness? Not at all. Bass? None.

Maybe they changed it on the JBL upgrade but stock, the rear feed is trash. Same speakers as the front, it's the signal that's the issue. You can see it with a multimeter if you removed the panels and tapped the speaker leads.

 

I don't know how to convince you, when I can't even convince the guys at the dealership. While there I managed to have 1 guy in management on my side, and we listened to both the base LE/SE system, along with another JBL equipped Prime. The base system is indeed trash, to the point he used the term "embarrassing" that they came like that, while the JBL was marginally better, but still nothing like how I remembered it.

Would you believe it if I told you that, what you're describing, and your perception of the system now, isn't how it was for me? I drove the car for 4 months, and throughout that time, while the system wasn't the best, it was acceptable. It was fairly tight and loud, until all of a sudden it wasn't, WHILE I was driving.

A week after posting my issue with my volume dropping, I went over to listen to a RAV4 Prime's system equipped with a nearly identical setup to ours. Sure enough, it was noticeably tight and loud . Now fast forward to April 22, 2024 I went back and the system was completely neutered. My friend was even baffled! Whatever the issue is, it is software, and it has migrated.



Soft_R, by the same rationale, next time you go back to your car, try this...

Have all your speakers CENTERED, and while you're listening, move your fader to the FRONT. If you sense absolutely no changes like I have, then clearly the system is faulty, as that's contrary to how a fader function is supposed to operate, then why bother coding it in to the interface at all.



*just a thought* I've been going under the assumption you're working with the Limited/XSE Premium JBL audio system, otherwise we're talking about two completely different product

 

Not sure if you misunderstood but let me be clear...

The front output CHANNELS (the signal) from the headunit give a different signal than what goes to the rears. This happens across many Toyota vehicles. Like the Tacoma: Low volume in rear speakers | Tacoma World more here toyota tacoma rear speaker volume site:www.tacomaworld.com - Google Search

It's nothing new at all. And I really doubt they changed that on the JBL.

And to be extra clear, it's not the speakers, it's the signal. I bridged my front door and rear doors when I redid my audio upgrade, wiring my the speakers in parallel which reduces the impedance to 2Ohm, and now my rears have much improved sound. Of course I lost front/rear fade doing this but I'd rather have a better listening experience for those in the back seat.

Oh look, more people talking about Toyota's weak rear signal and this time on the JBL platform: fixing the rear speakers in the JBL system | Toyota GR Corolla Forum - Ownership Discussion

If you guys just do a little reading first it'd save so much time.

 

Sounds like there was an issue with the amplifier in that car. I've have the Jbl and did not observe any change in the output over the last 14mo.

@soft_r : You are correct the jbl similarly does not give much signal for the rear door. I have also witnessed this in other Toyotas.

 

I appreciate your inputs, sounds like you know your way around car audio. With that said I'm also trying desperately to not make this sound like a pissing match, because we are here to learn from and help each other after all.

While I'm struggling with an audio problem not relating to this, I could not wrap my head around how you think this problem is NORMAL. I assume you know what a fader function is, and by extension what purpose it serves?

My '17 Corolla is balanced across all 4 main channels when centered. I know this, because I just changed out a pair myself . And to make this simple, so has every vehicle we own, and every one I have heard. Every basic to advance aftermarket head-unit has had something plastered across like 45W x 4 or something to that affect. Since when has Toyota audio systems start doing this 80% front 20% rear business?

The vibe I'm getting from Soft_R is that this is normal, it is known, and Toyota owners should just shut up?

 

Not at all, if anything as a consumer we should complain to Toyota to get them to change their tune

But as far as the actual hardware that came with our gen5s, we're kinda stuck with whatever signal the head unit outputs. It has no bass frequency in the rear speaker signal, and I hate it. It's been like this since day1 for me, as well as during my test drive (sales guy's personal car)

I added a Beat-Sonic ENA-2T3 on mine to clean the signal and boost the rear a bit since the front drowns it out. Then I'm probably going to follow PhoS and add a jbl basspro nano to round it out. Was really hoping for a full plug/play solution for the sub though

 

Rordon Gamsay, it's been well over a month, what's the status chef?

Looking at the available space I have under the passenger seat, it looks like there's about a 2-inch clearance at it's narrowest point. Did you manage to stick with that plan of installing it there?

In other news, I spoke with a buddy who installed the JBL Basspro Nano under the seat of his Gen4 Prime (haven't listened to it yet).

He says even though it fits, and the bass was adequate, the rattling of his seat at most level drives him nuts, and he wishes he hadn't done it. I'll probably be helping him relocate it to the rear at some point then.

 

Hammersmith,

By chance do you know if the two pairs of whites and greys for the FRONT CHANNELS are present in that connector? it is a bit hard to tell.

 

There should be no gray wires in this connector. The other connector has four pairs of Lavender/White Stripe and Solid White, but those are the power feeds to the speakers and not the signal feeds to the amp.

I don't know if this is going to make a ton of sense, but here are all the channels. I've tried to include all the info you'd need to find any input or output to and from the amp. The only applies to the JBL 8-channel audio system. I only labeled the (+) out of each channel; obviously you also need the (-), but it's a little clearer to read with only one of the two labeled.

Code:

From head unit to amp(signal) - not certain what the FB channels are for
FB1+   Black   10
FB1-   White    9
FB2+   Red     22
FB2-   Green   21
FR+    Black    5   Front(right)
FR-    White    4
FL+    Red      3   Front(left)
FL-    Green    2
RR+    Black   17   Rear(right)
RR-    White   18
RL+    Black   15   Rear(left)
RL-    White   14
24 pin rectangular connector
1  2  3  4  5  6  7  8  9  10 11 12
13 14 15 16 17 18 19 20 21 22 23 24
1  - Blue               12 - Violet
13 - ???                24 - Light Green

From Amp to Speakers(power)
FR+    Lav/Blue    14   A Pillar(right)
FR-    Lav/White   29
FL+    Lav/Green   12   A Pillar(left)
FL-    Lav/White   27
RR+    Black       15   Rear Door(right)
RR-    White       30
RL+    Blue        13   Rear Door(left)
RL-    White       28
WFR+   Lav/Black   10   Front Door(right)
WFR-   Lav/White   25
WFL+   Lav/Red      8   Front Door(left)
WFL-   Lav/White   23
TWR+   Red         11   Dash(right)
TWR-   White       26
TWL+   Red          9   Dash(left)
TWL-   White       24
30 pin strange shape connector
1  2  3  4  5  6  7  8  9  10 11 12 13 14 15
16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
1  - Red                          15 - Black
16 - Green                        30 - White

 

It makes sense to me!

I'll try to verify if those FRONT line ins are indeed pre-amp and are meant to go to the front (when I get around to doing mine.) Thank you much!

Shout out to PhoS for the reminder that the fronts might be the only ones getting the full-range signals.

 

Yeah, I gave him the wires for the rear outputs because that's what the instructions for the subwoofer said to use. But I tested my own sound system today and agree with those that say there's a problem with the JBL settings. If I were asked the same question today, I would recommend using the front outputs instead of the rear.