LOC Questions - 2024 Tundra / Non-Hybrid / JBL Audio

***1st POST!!!

Hello Tundra Owners!

I've recently joined the club, and, like many, I've noticed that the JBL audio/sub configuration doesn't live up to the expectations one might have for a truck costing 60k. We've come to terms with this reality.

As I move forward, I've researched on this forum and gathered tons of information. However, I have a few questions regarding the LOC (Line Out Converter).

There are several brands of LOCs available - the LC2i is apparently the most popular. Has anyone opted for the pro version?

Also, where did you connect your 12v source? Is there a designated area at the back of the truck, or is it necessary to run two 8-gauge wires to the battery for both the LOC and Amp?

I visited a local audio shop, and the technician shared some insights about our truck's audio system. It turns out that most of the speakers are not JBL, except for the subwoofer. The factory amp is designed to direct most frequencies (high, mid, and bass) towards the front, primarily to the door speakers and dash, which is evident from the rattling.

Another question: When using the LOC, which is post-amplifier, I would prefer to set the bass to the lowest possible level using the in-settings controls and direct all the bass to the subwoofer. With the LOC being post-amp, and by turning the bass completely off, how effective have you found this to be for the bass output on your dedicated Sub/Amp? Essentially, this would mean cutting off the bass frequency to the factory amp.

I'm considering the JL Stealthbox, despite the fact that it means giving up the under-seat storage. It appears to offer the neatest installation and accommodates an almost full-size subwoofer in the truck, potentially providing a superior sound experience compared to the ultra-slim alternatives.

If there are superior solutions for custom boxes, I'm open to suggestions; however, we're quite limited in space on the backside of our seats unfortunately.

 

Welcome to the asylum!
You've discovered the glaring flaw inherent in the 3rd gen JBL system. The sub is a ridiculous, worthless, waste of space, with the bass being biased heavily (mostly) to the front door speakers.
I've been lucky so far in that I don't have any door rattles....yet.
I am in the beginning stages of fixing this one step at a time. Step one is DIY box-building for a shallow mount single 10" on the drivers side. Amp on the center hump and retain the pass. side storage.
That's my "superior solution" for a custom box, because no one makes one I'm willing to pay for.
(We need a "tightwad" smiley.) I have leftover components from previous installs that should work well.
I know I can't get the internal box volume I need going with MDF box construction so I'm considering trying my hand at fiberglass. More on that in my own thread once I fully commit to it.

The JL Stealthbox at $1200 is outside of my realm of reality, and while it does use a 12" sub, it's still a slim/thin mount sub.
I'm sure someone has proven me wrong, but I don't think it's possible to fit any full depth sub back there?....Maybe a 8"?

I've used the non-Pro LC2i with good results in the past but not the Pro.
I'm using the LC7i on this project (also non-Pro) mostly because it's what I have.

Whatever LOC you use will not require a dedicated 8 ga.
The amp, sure, not the LOC. They don't draw much power.

There will be more (and more skilled) bassheads in here I'm sure that can help with your other questions. Good luck!

 

Indeed, I have examined the subwoofer installed in the JL Stealthbox (12TW3-D4 - Car Audio - Subwoofer Drivers - TW3 - JL Audio. The magnet is inverted, which, due to the design, might be considered full-sized given the magnet's dimensions. (My understanding could be incorrect, but this is based on what I have read and researched).

I am aware that the shop (tech12volts.com) comes highly recommended on this forum; however, I haven't found anything related to our '22+' model yet. This doesn't necessarily mean they cannot provide a solution. Regarding the LOC I have researched, it does require a full 12v power supply, and it seems I will need to obtain this directly from the battery since the subwoofer itself does not have a power supply connected to it.

 

In a JBL truck regardless of year you have a couple options. In any scenario, a LOC is always going to be pre-amp. The purpose of a LOC is to take high level speaker signal and convert it to low level for input to an amp. People like the Audiocontrol LOC's because they have their proprietary "Accubass", which is essentially a bass restoration knob. It's not as good as a full blown digital signal processor or a dsp amp, but it allows you to somewhat "fix" factory bass damping etc.

Idk if I would trust the local shop if they're saying the speakers aren't JBL in a JBL equipped truck. I'd imagine that would be class action lawsuit level if Toyota wasn't putting JBL speakers in when they say they are. The JBL speakers are easy to spot as they typically have an orange surround like this:



You can swap out the factory sub for a better one, but since the factory amp doesn't provide a ton of power for the sub, you'd be better served replacing the sub and adding an aftermarket amp to power the sub. Most amps nowadays accept high level inputs so you wouldn't necessarily need a LOC, unless you wanted it solely for the Accubass feature. Kicker makes a couple of amps called "Kicker Key" amps that have automatic digital signal processing. I've not tried one but am going to in the near future in my wife's car that has a Bose system. The Kicker Key 500.1 does 150w @ 4 ohms, 300w @ 2 ohms and 500w @ 1 ohm. Plenty of power for a shallow sub and the amp will auto-dsp the input signal to provide a signal to the sub that's not so throttled by the factory system.

Another option is to get a self-powered sub. Still have to get power/ground to it, but they can be a nice option depending on budget.

To summarize, a LOC is only needed if your amp doesn't accept high level inputs or if you want an Audiocontrol LOC for the Accubass feature. Most amps nowadays accept high level/speaker level inputs so you can get signal from anywhere. You'll need to run power wire for an aftermarket amp, but you can use a distribution block or piggy back off that power source for a LOC if you go that route.

Unless you're looking to add a ton of bass, a single shallow 10" or 12" sub with adequate power from an aftermarket amp should be a big improvement over factory.

 

Perhaps I'm overlooking something, but how does one use a dedicated amp without a Line Output Converter (LOC)? The signal must be sourced from somewhere to utilize RCA cables, right? If I were to connect to the factory subwoofer, the LOC would be post-amplifier. My confusion lies in the wiring of the factory subwoofer itself, as that would be my signal source.

Regarding your comment about the local dealer, I shared your initial reaction. However, they are a highly reputable company with over 30 years of history. I haven't verified their claim, which I ought to have mentioned earlier.

 

https://www.tundras.com/threads/jbl-audio-or-is-it.135043/


*edit*
So I just RE-read that thread after posting the link...
It seems it refers to the non-JBL 9 speaker system and another reply states the 12 speaker JBL speakers are CLEARLY marked as JBL.

Sorry for muddying the waters.

 

Yeah, I'd find it really hard to believe the speakers are NOT JBL. It was just his statement.

Moving onto the real question around LOC. Back on topic!

 

Sorry I meant that the LOC would be pre-aftermarket amp and you could put the LOC pre or post factory amp. I believe on 3rd gens the factory integration from AutoHarnessHouse is basically an extra male and female plug with about 6" of wire in between. It plugs in behind the head unit and you cut those wires to avoid cutting anything factory. If you ever sell/change things you can just disconnect those two connectors and hook everything back up factory. Link here: https://www.autoharnesshouse.com/82193_info.html

You essentially end up making your own T harness by attaching ~15' of speaker wire to one of the speaker outputs, and then route that wire to your new amp location for signal input. Amps that accept high level/speaker level input either have RCA inputs and you use speaker wire to RCA adapters, or they have they come with their own harness/plug and you solder/crimp directly to the bare wires coming off that plug.

It's hard to say where the signal is being processed in a JBL truck, or any vehicle for that matter, but getting signal before the JBL amp would also have the advantage of being less "noisy".