How To: 4 Ohm Resistor Upgrade For Aftermarket Dash Speakers

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JimGregory

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Hey folks, just so I understand this clearly, the 8-ohm load on the factory speakers is due to the factory wiring itself NOT the factory head unit correct? I plan to upgrade both head unit and speakers and just wanted to make sure that I'd still need to perform this step to normalize the sound. Thanks!

With my standard 6 speaker arrangement in my 16 express I AM TOLD that the dash speakers and front door speakers are joined. The factory put 8 ohm speakers in the dash so that the dash speakers would not overpower the door speakers due to their placement (in your face). I used 3 way JBL 6x9's in the front doors, 2 way JBL 6x9's in the rear doors and 2 way JBL 3.5's in the dash. I was MASSIVELY over tweeted. I put 4 ohm resistors then 6 ohm resistors then clipped the wire to the tweeters, added bass blockers, and ultimately just unplugged the ****** things.
Sounds great now!
Should I ever upgrade my head unit I will revisit the whole thing.
 

Matts175

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Hey folks, just so I understand this clearly, the 8-ohm load on the factory speakers is due to the factory wiring itself NOT the factory head unit correct? I plan to upgrade both head unit and speakers and just wanted to make sure that I'd still need to perform this step to normalize the sound. Thanks!

The short answer is YES, you will need to do this still. The SPEAKERS determine the ohms, not the wiring. So, If you use 4 ohm speakers and then run these 4 ohm resistors inline... you get 8 ohms... just like factory.
 

tnctx02

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What is the best speaker brand to install in the 4th gen Ram?
I had great luck over the years with JBL, Kicker, and Rockford Fosgate. My Alpine speakers were really good too.
I have never had any Infinity brand before.
 

Rherman1

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I have the kickers in the dash and the infinity's in my doors. I am very happy!
 

GeeZee

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This is a great write up and makes a fantastic difference. About a year ago I put some kicker 3.5" in the dash and pioneer 6x9s in all 4 doors. They sounded much better than stock, but the fronts were overpowering and I couldnt turn it up past 16 or so without distortion. Today I wired up the resistors (following the instructions here) and the results are very noticeable! Better sound stage and ability to turn it up much louder without distortion. I'm kicking myself in the ass for not doing this sooner.
 

BrazenHaven

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I am planning on doing this as well. Seems on the 19’s with the factory six the front doors have a lot of midrange and bass so maybe they are two ways? When you guys installed the doors were they already 4ohm and not 8 from factory? So you only needed to bring the dash down to 8 from 4 ohms? I haven’t taken my doors apart to check, but I wanted to see what your installs were. Also has anyone tapped into the rear doors to add subs?


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I am planning on doing this as well. Seems on the 19’s with the factory six the front doors have a lot of midrange and bass so maybe they are two ways?

There appears to be a smaller cone at the center of the stock 6" X 9" speakers but it's probably decorative. Hard to see as there is a thin, black dust cover over the speaker area. In any event, it is not a true coaxial speaker.

Here are some pics I took when I replaced my front door speakers:

Speakers-Front-Door-6X9-Stk.jpg

Speaker-Stock-6X9.jpg

Speaker-Stock-6X9-Depth.jpg


When you guys installed the doors were they already 4ohm and not 8 from factory? So you only needed to bring the dash down to 8 from 4 ohms? I haven’t taken my doors apart to check, but I wanted to see what your installs were.

That is correct. In the 6 speaker non-Alpine system, the door speakers are 4 ohms. Only the dash speakers are 8 ohms, so if the dash speakers are replaced with 4 ohm speakers they need to be brought back up to an 8 ohm load for the amplifier by adding the resistors.

Also has anyone tapped into the rear doors to add subs?

Yes, this is a common way to do it. You might need a line-out converter (LOC) between the rear speaker taps and the subs.
 
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CoZo6

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(Continued from previous post)

8. Repeat the process (steps #2 through #7) on the other end of the resistor and the other section of the positive wire.

View attachment 139003


View attachment 139004



The Preliminary Results

I removed one speaker and connected the resistor/harness assembly to it. I connected this dash speaker to my truck. I did not completely install the speaker, I laid its magnet on top of the dashboard. I now had one speaker with the 4 ohm resistor installed and one speaker without the 4 ohm resistor. Was there a difference in the sound output between the two dash speakers? Yes, but not as much as I thought there would be. I set the fader to fully front speakers and while playing music at a volume setting of 20 I moved the fader from left to right, and from right to left noting any difference in volume levels. The speaker with the resistor was not as loud as the resistor-less speaker but I expected more of a difference.


I put the fader back in the center position and played a couple of songs at volume setting of 20. This is a moderately loud setting. I fiddled with the equalizer. Played sections of songs I knew would be “treble heavy”. I suppose I did this for 10 minutes or so.


I wanted to see how hot the 4 ohm resistor would get. I cautiously reached for it and gently pinched it with my thumb and index finger….and….it was not hot, it was not even warm. In fact, it was basically the same temperature as the ambient air around it. That was a good result, I thought. That meant I could confidently crank up the stereo with no worries of this resistor getting blisteringly hot underneath my dashboard. The 4 ohm resistor wasn't hot because it was rated at 10 watts. Be sure to get 4 ohm resistors with a 10 watt power rating.


I installed the speaker with the resistor on the wiring harness, screwed it in place and replaced the cover grill. I then did the other wiring harness, installed it on the other dash speaker and replaced that speaker. I now had both speakers with 4 ohm resistors installed and in place.




The Results

I played some songs I knew were from good source material and had some dynamic range. “So Far Away” “ and “Money for Nothin’” by Dire Straits; “Abacab” by Genesis; “December” by Collective Soul, “Everyday is a Winding Road” by Sheryl Crow (Jeez, I’m dating myself…)


I kept adjusting the equalizer to tune the songs into what I perceive as good sounding. I noticed I was turning down the bass and turning up the treble. Here are my before and after settings on the equalizer, before resistors and after resistors. (Disclosure: I have an 8” powered subwoofer installed)


Bass
Before: +4
After: +2


Midrange
Before: 0
After: +1


Treble
Before: -4
After: 0 or +1 (depends on the album/song)


The system sounds much better. The most surprising thing, though, is that I can turn the volume up much, much higher and not get distortion. The max I dared to turn up the volume before the resistors was to about 24. At that level I could sense my brain didn’t want to listen to the music—there was something grating and raw about it. I can now go to 30 and not get the grating, harsh, “something just isn’t right” feeling. Now, at 30, it’s just too loud for my (old) ears!


I think the resistor install worked wonders to bring down the prominence and reduce the harshness of the dash tweeters. The system sounds better overall. There is less distortion. I can play the music louder. The front door speakers are more noticeable. All in all, a worthy mod.
I’m going to complete this mod soon. Just following up to see if your still pleased with the resulting sound performance with this resister install?
 
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PowrRam

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I’m going to complete this mod soon. Just following up to see if your still pleased with the resulting sound performance with this resister install?
Absolutely satisfied. I believe it should be a mandatory mod if you've replaced the dash speakers in the stock 6 speaker system.

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BrazenHaven

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I just did this and this write up was great so thank you.

I did find out by measuring the resistance on all speakers; for the base 6 speaker system on 19 new body, the dash are 8 ohms. and all the doors actually measure 2.3 ohms and not 4. According to the wiring diagram from crutchfield the dash and front doors have separate inputs from the radio but the output to the speakers are together.

I was wondering if anyone used the stock base amplifier and tapped into the speaker wires from there to connect an LC2i instead of coming from the doors?

I also purchased this cable to prevent the base amp from producing a drone to the aftermarket sub for the ANC.

https://lljcustoms.com/store?olsPage=products/2019-ram-anc-bypass


I was also thinking of adding a Kicker Key180.4 amp to give the new speakers a boost. I used all kicker CSC speakers. 6x9 3 way for rear, 6 1/2 two way for front and 3 1/2 for dash (of course I would replace the cable for dash to bring it back down to 4 ohms). Reason for the kicker key is it was made to integrate using factory wiring and factory amp.

Has anyone else done this or thought about it?

By the way if anyone needs the instructions for wiring let me know and I’ll send it to you. They include the stock amp wiring for all versions of speaker setups.


Sent from my iPhone using Tapatalk
 
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tnctx02

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I just did this and this write up was great so thank you.

I did find out by measuring the resistance on all speakers; for the base 6 speaker system on 19 new body, the dash are 8 ohms. and all the doors actually measure 2.3 ohms and not 4. According to the wiring diagram from crutchfield the dash and front doors have separate inputs from the radio but the output to the speakers are together.

I was wondering if anyone used the stock base amplifier and tapped into the speaker wires from there to connect an LC2i instead of coming from the doors?

I also purchased this cable to prevent the base amp from producing a drone to the aftermarket sub for the ANC.

https://lljcustoms.com/store?olsPage=products/2019-ram-anc-bypass


I was also thinking of adding a Kicker Key180.4 amp to give the new speakers a boost. I used all kicker CSC speakers. 6x9 3 way for rear, 6 1/2 two way for front and 3 1/2 for dash (of course I would replace the cable for dash to bring it back down to 4 ohms). Reason for the kicker key is it was made to integrate using factory wiring and factory amp.

Has anyone else done this or thought about it?

By the way if anyone needs the instructions for wiring let me know and I’ll send it to you. They include the stock amp wiring for all versions of speaker setups.


Sent from my iPhone using Tapatalk

Yes, would love to have a copy of it before I begin.
 

CoZo6

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Absolutely satisfied. I believe it should be a mandatory mod if you've replaced the dash speakers in the stock 6 speaker system.

Sent from my Nexus 7 using Tapatalk
I completed this update today. With the fronts not so bright, I get much better full surround throughout the crewcab. Thanks for the great write up and the recommendation. Most pleased.
 

Matts175

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I did this a while back and I'm still finding my Kicker 3.5 dash speakers to be a bit too "bright". As a band aid, I have the treble turned way down. Do you think if I went with some higher rated resistors, it might be better for me? Should I try the 5.1 ohm? Or should I go for the 6.2 ohm?

Capture.PNG
 

bchap05

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Hey all bought new dash and door speakers before reading this thread this weekend. The dude at the stereo shop recommended I get Hertz 3.5s and Hertz 6x9s. I noticed my highs were extremely high and dash super loud which lead me to this thread. Looked up the speakers and found out they are both 4 ohms. Unfortunately i couldnt find adapters locally so I just cut the factory wiring harness and put on spades. Since I did that I can't follow the first post exactly. If i get the ohm adapter will I just wire it to one of the wires before the spade since I don't have the adapter? And two if I get an aftermarket hu which I will eventually would this matter? Or is this just a factory hu issue?
 

Matts175

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Hey all bought new dash and door speakers before reading this thread this weekend. The dude at the stereo shop recommended I get Hertz 3.5s and Hertz 6x9s. I noticed my highs were extremely high and dash super loud which lead me to this thread. Looked up the speakers and found out they are both 4 ohms. Unfortunately i couldnt find adapters locally so I just cut the factory wiring harness and put on spades. Since I did that I can't follow the first post exactly. If i get the ohm adapter will I just wire it to one of the wires before the spade since I don't have the adapter? And two if I get an aftermarket hu which I will eventually would this matter? Or is this just a factory hu issue?

You just wire the resistor in on the + terminal side. Leave the resistor in place when you get the aftermarket head unit.
 

bchap05

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You just wire the resistor in on the + terminal side. Leave the resistor in place when you get the aftermarket head unit.

Perfect thanks. Any ideas if most stereo shops would carry something like this? Or will I have to order online. I'm impatient and hate waiting for delivery
 
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