Aftermarket Amp with Stock LX450 Head Unit

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smittycrusher

"Hey big guy, you a golfer" - Roger Dorn
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I need some help and hope that someone has gone down this path in the past. I have upgraded my four door speakers to Polk DXI 6500 components and removed the center "sub" in order to mount my CB speaker in that location. Obviously the stock amp is garbage and even though this set up sounds a thousand times better than the stock speakers, I want to by pass the stock amp and add my old school PPI Power Class 4 channel amp to these Polk's. I should expect to see another 1000 times better sound ;).

Here is the catch, I would like to keep my factory head unit. I have my reasons for wanting to keep the factory head unit and one of which is security from the "stock" look. Has anyone ever installed an aftermarket amp to the factory LX450 head unit? I know there are no pre-amp outputs on the LX450 head unit so I need to tackle that issue and I also will need to run a remote power wire from somewhere into the amp. I will plan to run all new speaker wire from the amp to the crossovers/speakers.

What am I missing?

Any ideas on creating the pre-amp outputs?

I searched and didn't find anythign so feel free to post links if you know of any other threads that would help.

TIA,

Smitty
 
SO i just found a few threads and it looks like my plan will be as follows (please critique and add suggestions if you have any):

1. Cut all output speaker wires coming FROM the OEM amp to the speakers.

2. Run speaker wire FROM the OEM amp for the FRONT LEFT and FRONT RIGHT speakers back to a Line Out Converter that also has remote turn on capabilities (near the amp location).

The reason that I am only going to tap into the FRONT speakers is that it appears that the LX450 factory amp uses high pass filtering on the rear speakers. I know that I will lose the FRONT/REAR adjustments at the headunit, but I will still have the gain and HP/LP adjustments at the amp as well as the crossovers that came with the Polk DXI 6.5" conponents. Since I am only going to have these four speakers in use and they are all the same, I figure that I can get away with not having FR/RR controls at the HU.

3. Use RCA Y-adapters from the 2-channel Line Out Converter to the FR/RR inputs on the amp (I know, not ideal, but I am not an audiphile and this is an off-road/bad weather extra vehicle that will not be entering any audio competitions).

4. Run new speaker wire to all four crossovers/speakers from the amp.

5. Dial in all of the gain/HP/LP settings available (HU, LOC, AMP) to my ear's delight. I am thinking that I will have the rears be a little more low pass biased while the fronts will lean a little more towards a high pass bias. This could all change as I sit in the seat and adjust to my liking.


As far as a LOC, I am thinking about these two:

LC2i - Audiocontrol 2-channel - $75.99

PAC SOEM-T-2-Channel - $16.08

I am not sure if the extra $ is worth it or if the less expensive version will suit my needs. I don't mind paying extra if I will actually get more out of it...that is not always these case with these types of things so I mush research some more. They both have very good reviews.


How does this sound to the 80 series powers that be? Any thoughts?

Smitty
 
if your a true music fan and want it to sound killer, Get rid of all factory components and go with a quality head unit.

The Head unit is the most important part, you cant polish a turd! and wouldn't you want ipod, aux, satellite radio, ect anyway
 
if your a true music fan and want it to sound killer, Get rid of all factory components and go with a quality head unit.

The Head unit is the most important part, you cant polish a turd! and wouldn't you want ipod, aux, satellite radio, ect anyway


X2 plus a pioneer double would only cost you 300 dollars and you get much better sound with your amps, I am in the process of adding a bazooka in the original sub area, but it seems tight, however the sound of your polks will be fantastic with the new head!
 
While I agree that a new head unit could be an improvement, it really is not an option. It is not a $ thing but more of a need to be discreet. I am planning to ship the cruiser out west next spring and may be keeping it out there for years (in Denver and Las Vegas). It is very important to me to keep the stock radio look as I will not be out there with it. It should be in secure locations at all times, but I still don't want to draw any unnecessary attention to it - the snorkel already does enough :)

I have heard some wonderful sound from stock head units over the years. I am really not concerned about the head unit as the amp and speakers are both killer. I don't need perfect sound for this wheeler but then again, I bet this head unit will surprise some people.

Smitty
 
I used a PAC unit similar to what your describing on my old Tundra. Worked great! I might still have it if your interested?
 
While I agree that a new head unit could be an improvement, it really is not an option. It is not a $ thing but more of a need to be discreet. I am planning to ship the cruiser out west next spring and may be keeping it out there for years (in Denver and Las Vegas). It is very important to me to keep the stock radio look as I will not be out there with it. It should be in secure locations at all times, but I still don't want to draw any unnecessary attention to it - the snorkel already does enough :)

I have heard some wonderful sound from stock head units over the years. I am really not concerned about the head unit as the amp and speakers are both killer. I don't need perfect sound for this wheeler but then again, I bet this head unit will surprise some people.

Smitty

So why do you have a need for amps, is it bass that you are looking for? Just get a powered sub, cross over your components and you will be blown away with the sound, your components will be more dynamic after you reliefe them from working so hard on the bass! Plus you will not have to work on your doors to avoid the rattles you will get with the extra power from the amps!
 
Don't need a lot of bass. Just the bass that the mids provide. I feel that these 6.5s will provide enough bass and balance with this amp pushing them. I don't want a sub as I am not looking to give up any cargo space or have anything else to attract/tempt wondering eyes. These 4 component 6.5s should be a huge upgrade over stock in ALL areas and that is all that I am really looking for. I think that the stock head unit will do just fine. If I find that I am wrong, I will get a new HU and run the RCAs that I already have from that deck to the amp and be done with it.

Smitty
 
Great, let us know how much you like your set up after the amp install!
 
stock head

Just swap out the stock for a better double Din. Take pic of stock head, enlarge and laminate and place in front of double D went not in use. Some very good color printers out there these days.
I'm thinking about skipping out on buying a winch and just use a pic.:doh:
 
Just swap out the stock for a better double Din. Take pic of stock head, enlarge and laminate and place in front of double D went not in use. Some very good color printers out there these days.
I'm thinking about skipping out on buying a winch and just use a pic.:doh:


What the :censor:
 
Go for it!
Don't let anyone tell you the factory HU isn't capable of high fidelity.

This is the road I went down too, only I'm using an EQ for fader control (maybe that was my thread you saw about the amp using high-pass filtering for the rear).

Here's what I found: The fronts have great low-end response, but have a little dip around 100Hz. The rears, having smaller doors, actually accentuate the frequencies around 100Hz, and sound a little "tubby", so adjusting the fader works as sort of an equalizer to smooth out the bass. I usually keep the fader set about half-way to the front, but you can do the same with setting the amps' level controls.

For the line-out converter (LOC) I used the 4ch Scosche model from Wal-Mart ($20). The extra channels are feeding my sub-amp.

Here's the nearly 30 year-old gear I used (dig the gooseneck EQ with analog VU meters!):

Amp-EQ.JPG

BTW, the Polks sound amazing and handle a great deal of bass. High-pass filtering is not required.

Amp-EQ.JPG
 
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BTW, the Polks sound amazing and handle a great deal of bass. High-pass filtering is not required.

X2 plus you will be hitting peaks way above 105 dbs which depending on your age could be harmfull to your hearing!
 
Progress pic. Taking a while to do since I can only sneak about 30 mins at a time to work on it. Only one more speaker wire to run (all new speaker wire being ran). Amp will be mounted under the driver seat.

Amp power/ground wires are done. Still need to run the remote and LOC wires from dash. Should have all speakers wired and mounted tonight.

Btw...that picture was taken at night with just PFrans LEDs on (3 domes and the doors)...those things are amazing and I have been thrilled over and over again with such a simple and inexpensive mod! Order yours here:http://www.pfranleds.com/

Smitty

image-4086478195.jpg
 
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Finished running all of the speaker wires last night. Also buttoned up the rear speakers. I am digging the component look.

image-2479254649.jpg
 
Looking forward to seeing where you placed the front tweeters.
 
Amp is all wired up and functioning. Sounds a lot better. Jury is still out on the LOC. I am getting a little noise and the amp can certainly "amplify" it. It still sounds MUCH better and the components are a lot happier with the power.

image-1551618607.jpg
 
You are going to be dissapointed.

Smitty

I put my tweeters on the pillars angle to the driver and passanger and I get good soundstage I also boosted my tweeters 3+ DB on the crossovers but I am old!

I have a feeling you installed your tweeters down by the mid/woofer?
 
I have completed the speaker/amp install and wanted to do a brief write-up for anyone else that is looking to upgrade speakers while adding an amp to the factory head unit. There are a few things that I had to go back and re-work (which meant taking the seats out and taking apart the center console again). Overall I am VERY happy with the results even though an audiophile would find faults. The Polk Audio DXI 6500 components scream with the amp and sound MUCH better than the stock system could have ever dreamed.

Here are a few thoughts from the install:

Parts:
PAC SOEM - T Line-Out-Converter from post #2
Precision Power (PPI) PC4400 amp (50 watts x 4 RMS - clean old school power)
2 sets of POLK DXI 6500 component speakers (6.5"woofers, 1" tweeters and passive crossovers)
2 Esoteric Y adapter RCAs
50 ft spool of Monster Cable 16-guage insulated speaker wire (Here at AMAZON)
Various butt and spade connectors

- I ended up tapping into the front left output speaker wire from the factory amp. I then attached that wire to the factory sub wire at the amp (I had removed the factory sub years ago when input my cb speaker in it's place). I then simply tapped into the sub wire where it comes off the factory harness under the center cosole. I grabbed it before it plugs into the black "sub box" (blue and white wires). From there I only needed about 14" of speaker wire in order to reach the LOC that sits under the seat by the amp.

- I only used a 2 channel LOC. I used two Y adapter RCAs in order to attach the two outputs from the LOC into both FR and RR RCA inputs on the amp. I can then use the FR and RR gain to adjust the fade...if needed.

- Since I was mounting the amp under the driver's seat and my keyless fob has been missing for years, I decided to go ahead and remove the black alarm box as it was of no use. At the time, I didn't know that I also needed to switch some connections by the left foot kick plate in order to have the truck start again...I thought that I had a dead battery the first time I tried to start the truck after the amp install. I am attaching a pic of the two connections that I switched in order to bypass the starter interruption that occurs when the black box is disconnected. Once I switched these connections, life was good and I was very relieved to have mud to utilize in finding this solution. Btw, I had the RS9000 box.

-Make sure you have a VERY good ground for the amp! I had some noise after the initial install (at first I thought it was the LOC) and had to take everything apart to sand the ground area down more (I should have done a better job the first time...I knew better). My ground for the amp is under the center console. I have no complaints about the LOC. It is serving my needs perfect!

- Component speakers are the way to go! The passive crossovers combined with the amp's active crossovers in the amp add a great deal of flexibility and the separate woofer and tweeter increase performance.

- Even though I am sure sound quality could be better, I chose to mount then tweeters for the front in the same location as the factory dash tweeters. I may at some point change this but I just couldn't decide on a location in the door that I was happy with and therefore didn't want to drill 2" holes until I thought about it more. I guess that another benefit of this will be the lack of visible components to wandering eyes as many will then correctly assume that there is an amp in the truck. The rear speakers do have the tweeters mounted near the woof and aimed up. The more I think about it, I may just mount the front tweeters on the black plastic cover for the by the side mirrors. I figure that I can use some SUGRU and get them mounted up good without having to drill anything. I will be able to point them at the driver and passenger directly (will probably use the -3db setting on the passive crossover to start.

- I ran all new speaker wire and although it was tedious, I think it was better than running wire all the way back to the factory amp location and connecting it to the the factory output wires from there. I used a cheap 50 ft spook of Monster cable wire that I got on amazon. I liked this wire as it was not only twisted but came in coated in a plastic sleeve of protection. These new wires were bigger as well so maybe they will be better for the higher wattage that the amp is pushing (I really don't think there will be a difference since I am only running about 50 watts RMS to each speaker.


Here are the pics:

#1 - Factory amp where I tapped into the Front Left Speaker output and combined it with the wires that run to the sub.

#2 - Here are the two connections that you need to switch if you remove your black alarm box (truck will not start until you switch these). They have blk and white wires leading into the plugs.

#3 - Rear door speakers with tweeters. There is no metal behind the panel where these tweeters are mounted. That was nice as I only had to drill the 2" hole in to the panel for the flush mount kit from Polk...very easy to install. Speaker did not need spacers but did need a larger hole than stock.

#4 - Front door speaker. I did use the spacer that came with the speakers to enable the magnet to clear the window rail. I did not have to make the hole any bigger to fit the speakers up front. There is about 1/4" gap between the grill and the side dash when the door is closed

factory amp LOC.jpg


starter switch.jpg


rear door speakers.jpg


Front speakers.jpg
 
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