New info JBL system lower ohms to increase volume

Thanks yes the XM radio daisy chains into those plugs. I appreciate the diagram. Where can I find schematics?

 

You can't. It is available via subscription on programs like Mitchell or Alldata, additionally there is the FSM from Toyota..

I can get you any wiring diagram you need if you want. If you need JBL radio info, I can post up all the info I have on it.

 

Thanks. And thanks for maintaining the IP. I have tested out my ports and the ones labeled are same as what I saw. I don’t really need to know what the ones I’m not experimenting with are anyway for now.

I found the FM cable adapter on Crutchfield and ordered a 1/4 wave aftermarket FM antenna. I’m going to experiment with it and if I get better reception I’ll likely install a motor mount antenna so I can still off-road with out gonquelating it on branches. Will be a few weeks before I have the parts and time. Really appreciate soundboarding with you today. Thx

 

It’s extremely frustrating the the entune in my wife’s 4R (no JBL) blows my Tacoma JBL out of the water.

OP - if you’ve stumbled onto something here, and can improve the performance of the JBL system fairly easily by re-wiring the sub....you will be rewarded with a sticky and thousands of likes. We will make you the Prince of Tacoma World.

 

Okay. Well using a aftermarket dual voice coil single set of inputs sub worked. So I guess I can try the stock sub rewire and see is I can? It's been 3 days. I can also give backup to my story about the placebo effect. My girlfriend didnt mind when I cranked up the volume before. She and I in fact could talk over the radio at full volume. Um last night going to dinner she gave me the "look" to turn that shit down and we definitely couldnt talk over the radio and it wasn't even turned all the way up...... I will work on the stock sub today

 

Some big discoveries affecting thousands of enthusiasts are made on these forums by members who tried something new, experimented around and started threads. I'll take ten threads a day about how someone discovered something new while tinkering around with their truck over the countless bitch and whine-fest threads that are posted here every day.

Years ago on the Cummins forum - 2009 or so - as the community was reeling over the new emissions laws that had resulted in turbo-choking EGR, efficiency and performance-robbing DPF and regen set ups...a poster noted that while cleaning his sticky EGR valve he discovered that by unplugging the plug, it remained closed and in the bypass position. He quickly reported back that he had fewer regens and much improve mileage. At first a cowardly pack of jackasses poked fun at him and doubted his claims, until more and more people started trying it and reporting back similar results - including increased oil change intervals and better overall performance. It almost singlehandedly negated the gummed up turbos, shitty mileage and other issues associated with the first non-SCR emissions systems on these diesels.

To this day, the 2007.5 to 2011 Cummins command a higher resale value among enthusiasts over the 2012 because one forum member posted about this discovery.

Pretty soon, everyone was unplugging their EGRs. It got so widespread that word got out and Cummins/RAM made it that the 2012 MY Cummins would go into a semi-limp mode if you unplugged the EGR.

Nate, if you've found a work around for the muddy sounding JBL system and it proves out, a shit load of us will be in your debt.

 

I just confirmed. I'm at work so it was done quickly but I wanted to get this confirmed as quickly as possible. But I need a unbiased tester to actually confirm. I just did it and it's safe. Just switch the stock wiring from positive to negative. Both sets of terminals. I'm blasting my truck at full volume right now while I'm working to confirm it doesnt turn down.

 

So I have this speaker lying around
8” 2 ohm shallow mount you think it would work OP?

 

It keeps the amp at a 2 ohm load x2 so just switching it is just reversing the phase

 

Testing against stock first to avoid people having to buy a new sub. I also have the pioneer p2002 or whatever it is dual 2 ohm and it played highs better but stock hit lower. The pioneer also did not distort. But again it wasn't loud

 

I'll confirm this afternoon.

 

I did that once, hurt real bad.

There's gotta be a way to mount an FM antenna in the bed, inside the cab, under your roof rack, or some where safe from getting bent.

Or you could consider ditching FM, Pandora offline mode is the best.

 

Testing now for a hour. Still at work. Seems we have 2 things going on here. Heat and sub capability. I got the amp up to 125 measured on the top portion of the amp. Since I've had my back plastic cover off the amp has had constant airflow so at full volume it's never got over 104 degrees with no plastic. I just covered the amp with a sweater simulating no airflow plastic and observed the amp turning down. Soo I cooled the amp and now back to consistant full volume. As for the bass and sub I will have to dig a little deeper about the ohms. Since the amp is 2 channel dedicated for the sub bridging 2 ohm should load the amp to 1 load for the sub but that's with a traditional amplifier. This is by no means traditional. Since it is low power and not driving a 1200watt 12" sub and u cant adjust the amp too high I feel it's safe to change the sub to a better sub.

 

You want a dvc 4ohm sub, so you can run at 2ohm load

 

On the oem sub You have 4 inputs for the dvc. +/- on each side. Disconnect one positive wire from one side and one negative from the other. Leaving one positive on left and one negative on right. Should be bridged then and running same as OPs CV sub.

 

He'll need too add a jumper across the coil terminals though no? The OP's Cerwin Vega is doing this internally with a little switch plug thing. Otherwise he'd just have an open circuit or be missing one of the voice coils.

****This has Been Updated and the Picture is Wrong*****
A dual voice coil sub without internal switching Should look like:
Positive from truck on Voice Coil 1 Pos with a Jumper to VC 2 Pos
Negative from Truck on on VC 1 Neg with a jumper to VC 2 Neg

Or you can reverse the polarity by switching the truck Positive and Negative which may or may not already be the case with the stock sub.

 

I have been reading this thread religiously and I will be honest most of this stuff is going over my head. However, that being said I have a few questions maybe some of you can answer or help me with.

AMP:
1. If the stock amp is such a limiting factor why not change it?
2. Would this be incredibly difficult to do?
3. How much rewiring would be required?
4. How likely are you to blow the amp if you bridge the sub, like people are suggesting?

SUB:
1. Would you be better off replacing the sub with something that will fit in the stock enclosure before messing with the connections?

 

AMP:
1. If the stock amp is such a limiting factor why not change it?
- It's sort of married to the head unit... it's a complicated relationship.

2. Would this be incredibly difficult to do?
-Not if you replace the HU with it. Some have left the OEM amp and sub while adding a new amp to drive the rest of the speakers fairly easily.

3. How much rewiring would be required?

4. How likely are you to blow the amp if you bridge the sub, like people are suggesting?
- bridging an AMP reduces the resistance in the circuit allowing more amps to flow at the same voltage which translates into heat. too much heat can be an issue which is basically what this thread has been about. With the aftermarket sub, it appears the OP's sytem has been doing fine

SUB:
1. Would you be better off replacing the sub with something that will fit in the stock enclosure before messing with the connections?
-That's what this thread has ultimately been about but in doing so the OP changed the wiring up a bit and has possibly struck audio gold. The OP is Running a 4ohm dual voice coil Cerwin Vega Sub with the voice coils bridged to drop it to 2ohms. Then it appears he has also bridged the amp dropping the total resistance to 1ohm and the sound is louder and more clear without having heat issues with the AMP.

The bigger picture is that somehow doing the above, the OP's entire system is working better and no longer automatically turns down the volume etc. The theory is that the factory sub may be wired in reverse polarity and the speaker would prematurely bottom out / clip. We believe that the amp is smart enough to detect the speaker clipping and would therefore limit the volume as a safety feature. Currently the OP along with another member or two to are testing out this theory in the event that simply reversing the polarity and bridging the stock speaker might recreate the magic. I'm guessing if the above assumptions are correct a sub that can handle more watts will still play a role but that's little more than a SWAG on my part.

 

^ I kinda understand it more