Hey guys, I'm new to the forum, and new to Acuras, but I have fairly adequate technical skills. I just bought an 04 Acura TL with factory in-dash 6 cd changer. I've been reading for hours on this forum and others, and I think I have a good idea of how to remove the stock subwoofer and add a new amp and sub. The only question I haven't found an answer to is this: Every single post I've found on doing this says to use a LOC after the factory amp (in the passenger kick panel thing) and use its RCA's to plug into the high level inputs on my new amp. Since my factory head unit has subwoofer controls, can't I just disconnect the subwoofer preamp wires ((SW+ Red w/Blue) and (SW- White w/Green)) that go from the HU to the factory amp, and reroute them into my new amp? Wouldn't that allow me to retain subwoofer control through my factory HU, while avoiding using an LOC which can cause electrical unbalance and noise? The only problem I fear is that those subwoofer wires don't carry the right voltage, and if that is the case, can you correct the voltage somehow? Thanks so much for your help! As soon as I get a definitive answer on this issue, I will take pictures of my install and provide a super-detailed tutorial for any other people curious about doing the same thing.

 

Possibly could work, but you would need a LOC anyway. Noise wont be a problem for sub channel

 

You don't need a LOC if you are using the HU-out pre-amp signals. I run my system this way. The HU outputs an approx. 1V pre-amp signal.

The only drawback to using the HU outputs is that you are using the HU crossover and this may or may not be where you want to set your crossover with your new sub.

 

I would love to see that !

 

Depends on your amp. The signal is pretty low. I know the amp I bought supposedly will handle down to .2v though. I'm going to give it a try and then buy a line driver if need to. From what I've been able to gather its better to use the pre-amp signals, but easier to use the post-amp ones.

 

I have also been doing some extensive research on this. From what i have found, the preamp wires that goto the OEM amp can be installed directly to aftermarket amp. The only problem with this is the low ~1V signal from the preamp wires. Using them will require a high gain setting on the aftermarket amp to compensate. The only way to fix this is to add a line driver. ie connect preamp wires to line driver and the output of the line driver to the new amp. But line drivers tend to be expensive.

Since i'm only adding an aftermarket sub&amp for now, i am going to wire my preamps straight to the new amp. When im ready to upgrade my whole system, Im going to install the "audiocontrol matrix." Its a 6input/ 6output line driver, perfect for our 5.1

 

I think the real question in this situation is what adds more noise? high gain on your amp(1 device), adding a line driver(2 devices),or using the stock amp with a loc (3 devices).

Part of the reason I'm avoiding a LOC are the stories of low end roll off with even quality LOCs on diyma.

 

I just found this thread. If what this guy claims is true, then it completely throws everything i have heard on acurazine out the window!!! Guess it's back to the drawing board... Looks like the LOC is the only option that will allow control with the factory HU.

https://acurazine.com/forums/2g-tsx-audio-bluetooth-electronics-navigation-304/my-els-audio-upgrade-els-preamp-819501/

 

Just a quick point. If you hook up the sub after the stock amp the signal will already be x-over at 80hz. I did my 08 Accord this way.

 

Just to throw in my .02, from my research and what I've understood from it is that that crossover points are set from the factory amp and that the signals from the HU were full range and flat. That's why it's recommended to pull the front and rear speaker inputs pre-amp. Doing it this way allows you to crossover at whatever point you choose. Why can't you just solder on a set of RCA's pre-amp and run that to your sub amp, as long as your sub amp will accept the 1v input voltage?

My install is happening as we speak and my installer is taking front and rear inputs pre-amp and installing a LOC for the sub. If I don't like the LOC, my amp accepts high level inputs and I can just wire the input directly from the sub connector to the amp.

The question I have is, where does the attenuation come from when the volume is increased on the sub? I have read this multiple times that the sub is attenuated to prevent damage when higher volumes are reached.

 

Gain on your amp is to normalize the input signal. Low signal and high gain is the same thing as high signal and low gain. Just set the gain to match the 1v signal and it will sound good.

Unless you have a turd of an amp, then adding line drivers and LOCs will take away more signal than using the amp gain properly. IIRC, using full-range LOC will do something like -24db per octave under 100hz - but look this up for sure since I am old and stoopid anymore.

I initiall wired my pre-amp sub signal directly into a twisted pair RCA - I can promise you that you can control the sub this way from the HU. Even the pre-amp sub channel is crossed about 80, so if you want it higher, you need to use the pre-amp front signal which is full range. Now, I have the sub wired to the front channels (like the components) and crossed over 100hz, but lost HU sub control since that channel is effectively not hooked up anymore.

 

From my testing, the front and rear signals are full range and pretty flat - I tested it to 25hz, but IHC tested it down to 10hz..it will go up to about 22Khz which is more than most amps go. The sub channel is from about 30-80hz. The center is 300-400hz and up.

 

good real world example.
http://www.diymobileaudio.com/forum/...stall-log.html

 

The actual freq response graphs are on this site somewhere, POST stock amp the fronts are full range and the rears ARE bandpassed.

 

where is the pre amp unit located

 

Factory amp?

Passenger side kick panel. Below and to the right of the glove box...

 

There is no "unit." The wiring harness towards the front of the car going into the stock amp are the pre-amp wires that come from the Head Unit.

 

About to make a Sticky with all this info lol so we can just reference it

 

 

New member. Just picked up a 2007 TL-S. Looking to move all my audio equipment over to this car. I will be replacing front and rears with components, and putting sub box in trunk. I have a 4 ch amp for front/rear and another amp for subs. Amps only have RCA inputs. Can I not just solder RCA cables onto preamps for all channels? I have been reading for hours, but no one really has a clear answer. I just want the cleanest sound possible. Thanks for the help.