Did this work?

 

Yes. That works.

 

Sorry i know this thread is old but just wondering, you unplugged the subwoofer then wired in the LOC, after you said do not plug it back in, do you leave it unplugged indefinitely and just not use that sub anymore? Can you use both subs? Thanks

 

Yep, leave the other sub disconnected, you're just going to muddy up the sound with a crap sub going while a good sub is. Even better, remove the old sub completely so you have a port for the bass to pass through from the trunk into the cabin.

 

Exactly! I never thought to remove it but that will definitely help.

 

So the OP says to run the wires from the Old sub to the Line out converter, then to the New Amp inputs... If you do this you are getting the already Processed, amplified signal from the Bose... which is then amplified by the New amplifier.... I would think you would want to take the signal before the Bose Amp... Am I missing something Here?

 

Correct. If you grab the pre-amp signal in my opinion, it's a bit on the weak side. Therefore you need to turn your amp up and depending on the quality of people's amps, run into the distortion or "dirty" power. By grabbing the already amplified signal it's a lot stronger signal and people will find they don't need to set their amps as high to get the output they're looking for.

I approached this from the "n00b" perspective from working in stereo shops and running my own business. Can't tell you how many people walk in saying "my stuff blew" and when I go look at the amp, all the dials are maxed out.

I've found its better to have a strong signal and have to turn it down rather than a weak one and people crank everything up to the moon.

 

You're missing a couple things - #1 being that the signal to the bose amp is a differential balanced audio signal. After the amp it's a standard unbalanced signal. #2 is a bit more minor, but there's no separate subwoofer channel, so you only have full-range audio signals to work with, while using the subwoofer output gives you just the low end.

So, yes, in general using a less processed channel is better, but unless you have an amp that can accept a differential-balanced signal (JL Amps do, but not many others do) you're going to end up with half the signal.

 

Dude thank you so much for this post! I have an 09 G37 and I got to the point of hooking my LOC up and my wires didn't match! Read through the rest of the thread and came across your amazing post that saved my day. Thanks again man!

Also thanks to OP for such an HQ tutorial!

 

Extremely sorry to kick this old horse but.... is there any difference in using the loc rca vs using the speaker level inputs on the amp. I am about to hook up the Fosgate p300 12" powered sub (Dont hate, it fits my situation) and I didnt pick up an loc. Any suggestions with this sub in mind would be appreciated. It says it can be used in "any system" with high and low level inputs. Thanks in advance.

And thank you to the pioneers of this thread, it has undoubtedly helped hundreds if not thousands of people.

 

I have read the first few pages of this thread a few times over the years and likely will go back and read it over again some more, but I think I am finally ready to try and get my old setup into the G. Some things are still going a bit over my head so I am hoping someone can answer a few clarification questions for me. Sorry if they seem like they are obviously answered already, I can't get things straight so I am hoping for a concise post to sum it up for me.

Background:
I have an old JL 12W3V2-D4 in a ported enclosure that I would like to resuse.
I have an old TMA 500 watt amp that will hopefully be usable (with a LOC) and not force me to buy a new amp.
I do have the Bose audio G35X sedan.

1) Am I correct in understanding that my existing amp will work as long as I add a LOC? Or do I still need to look for specifics such as the balanced input and other specs and not every amp will work even with a LOC?

2) Assuming my existing amp works with an LOC, will my setup sound very close to what it would sound if I instead bought a new JL 500/1 amp that works without the need for a LOC? (I am not wanting to spend more money than I have to on this.)

3) If I do need to get a new amp, is a 500W the size I need or would a 250W work fine? I feel like I saw some using a 250, but they may have had a 10" and not a 12" which may make the jump in power.

4) I assume the hardest part of this install is running the power wire from front to back, is that correct? I want to maybe pull the pieces out and see how difficult it would be before going all the way with it. If something else would be the hardest part of this install, then please let me know what you think it is.

5) I remember reading about some also running a line for the sub control (gain maybe?) to the front so you can adjust it on the fly. Is this something that is highly recommended or is it possible to just set things up to a decent level on the amp and not have to touch it again? I assume the radio controls will do very little to adjust for various songs or people in the car, but I am not sure I want the extra hassle of running another wire and control **** somewhere near the driver.

6) While I am asking questions, I don't have the enclosure with me so I will have to get measurements later, but roughly how much space is required for a ported 12"? I have a feeling my box is much bigger than it needs to be and would consider getting a new one if it will give me noticeably more trunk space. I think if I did reuse the one I have now, it would fill the entire back smaller portion of the truck rather tightly so it seems like it is more of a box for dual subs and not a single.

Thank you to all that have created and contributed to this thread since the beginning, I have a feeling that once I get my old equipment installed I am going to wonder why I didn't do it 4+ years ago when I first saw this thread. Other than confusion I suppose my only other excuse was the trunk space lost with my current box.

 

I know this thread is fairly old overall, but I can't see it being inactive, can anyone at least answer some of the above questions please?

 

Sorry, missed this one when it was new.

Yes, it will definitely work if you keep the factory amp and put your LOC after the factory amp. If you take the signal before the factory amp, you're dealing with a differential-balanced signal, which few amplifiers can use properly, but keeping the factory amp introduces a TON of equalization done by the bose amp. I'd recommend trying the signal before the bose amp without a LOC first. If the sound quality is acceptable, don't do anything more. You can avoid the whole guesswork by going aftermarket with the headunit and cutting out bose stuff completely.

No, you're getting a heavily equalized signal after the bose amp.

500W RMS is about right for that sub. 250 would be worked near/at its maximum capacity, which causes more distortion than the 500w would have at the same output volume.

Running wires is the worst part, but not bad in these cars. Through the boot by the battery box (seal the new hole well!) downt he passenger footwell, and under the carpet in the trench all the way to the backseat, under that and you're in the trunk.

Not necessary, but if you like to alternate between what sounds good and what sounds a lot, you might want one. Aftermarket headunits commonly have a dedicated subwoofer line and gain control, so that's a good reason to swap headunits too.

Ported 12" box would be pretty big, about 1/2 the trunk when done right. You can look through the custom installs thread for an idea.

 

No worries, I really appreciate your time in answering all of these for me Wrathernaut.


Ok that makes sense when you it explain it this way for me. If using an LOC you have to go after the amp which isn't ideal, but at least is able to work. I think I want it to sound the best I can without replacing everything so yes no harm in trying my current amp before the factory amp and if it doesn't play well with the differential-balanced signal, then I can still use the tapped wires on a new JL amp to do things properly. I don't feel like paying $250+ for a bezel otherwise I would change out the headunit as well.


Thank you, I plan to avoid this setup then so it can sound as good as possible while still using factory everything else.


I have to do more reading on amps, but it seems like the newest JL 500W monoblock amps are the JX500/1D i believe it was. This mentioned 500W at 2Ohms and I think 300W at 4Ohms. My W3V2 is a 4 ohm model so it looks like I will be putting 300W to it and will hopefully be similar to my current 11 year old amp that is 500W, I'm not sure what wattage at various Ohms.


I know I read to seal with silicone or something similar, will re-read and definitely do, but is it as simple as squirting some around the wire and it actually stays there? I'd think it would just drip down over everything, but never used it before. Just making sure there's nothing special.


Good, I can at least start without one and see if I have many needs to want to lower it.


I got someone to measure the external dimensions for me which are 32.5"L x 14.5"D x 13.5"H. I am not sure of the internal port length to figure out how much to remove, but it sounds like I am likely at the large end of recommended size, but not likely oversized. I doubt I could go crazy noticeably smaller (without going sealed) so I will stick with this box. I think the ones I have seen that are like half the size are either slim subs, 10", or just in a smaller than recommended box.

Thanks again!

 

RTV silicone won't drip. You're basically just going to put it like cake frosting around the hole you cut after the cable is completely run (so leave some slack in the battery compartment), then pull the power cable about a half inch through to get a little of it on the inside. Easy to work with, and it will peel off it you ever have to remove it, but can definitely be considered permanent.