How To: 4 Ohm Resistor Upgrade For Aftermarket Dash Speakers

[OC455]

(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 just did this for the 3.5's I put in my dash...not as pretty as yours, but it works.

 

[PowrRam]

I just did this for the 3.5's I put in my dash...not as pretty as yours, but it works.

After you've listened to them for a couple of days please report your findings.


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[OC455]

After you've listened to them for a couple of days please report your findings.


Sent from my Pixel 2 XL using Tapatalk

Will do....I can say at this point listening to XM 80's on 8 (don't laugh, they were playing songs from movies so it was a good start as I now how the songs are supposed to sound), the highs were really brought out across the front and the dash as it seems. I adjusted the equalizer and the bass was running at 1, mids at 1 and treble at 3. The Hifonics 3.5 2 ways don't sound to bad right now. My Hifonic 6x9's are supposed to be here tomorrow according to the tracking I received.

I know Hifonics are probably not as good as some of the other speakers brands, but they are pretty good as far as I can hear with my ears.

 

[OC455]

After driving around with them for a few days, the 3.5's still sound pretty good. My 6x9's came in today, (3 ways), was able to install in the front doors. Seems the highs are now a bit washed right now. Had to drop the bass to zero because the bass was really prevalent when I added the 6x9's.

I have the 6x9's for the back that I am going to try putting in. I used 6mm-1/4inch spacers for the front door 6x9's. Would I need to get another set of spacers for the rear door 6x9's?

I played with my EQ a bit more, dropped the bass to zero, mids at 2 and treble to 5. Sounds much better with those settings. The highs are coming out where they belong.

 

[Bill507]

I just did this for the 3.5's I put in my dash...not as pretty as yours, but it works.

Following thread, have same ceramic resistors and kickers. Doing mine this weekend.. good to know its worth the effort to put kickers back in at 8 ohms. Thanks guys for your details and results..

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[Irongoats]

Nice writeup just ordered the parts.

 

[OC455]

After you've listened to them for a couple of days please report your findings.


Sent from my Pixel 2 XL using Tapatalk

After a few weeks of running around with the Hifonics 6x9's and 3.5's with the resistor mod done, I can say that it does sound much better than factory. I had to tweak the EQ settings on the radio to bring out the highs better throughout. Bumped the treble and mid bass, didn't touch the bass zero'd out. The bass hits pretty good through the 6x9's.

As was mentioned in one of my threads, I believe I was experiencing some phase cancellation in the highs and that's why I had to adjust the EQ a bit to bring out the highs some.

I know the Hifonics are on the cheap end of the scale as far as speaker upgrade is concerned, but they do sound pretty good for OEM replacement speakers. I do not plan on running amps, or a sub, so these suit me just fine.

Very pleased with the speaker upgrades.

 

[61N150W]

Big thanks to @PowrRam for the heads up on these resistors. I was able to find a 10 pack locally for $5.00. I already had the harnesses since I had purchased from Crutchfield (they include all hardware)
I had replaced my 6 speaker system with Kicker CS all the way around. These little guys took 5 minutes to make but much improved the 3.5s in the dash.

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[JimGregory]

I believe after dicking around with my JBL Club 3.5 speakers that I should have used possibly a 6 ohm resistor.
I was overtweeted with 3 ways in the front doors and coax in the rear doors. The rear coax's were a waste of money though. Component woofers would have done better.
Anyway I went with 4.5ohm resistors and nipped the tweeter feeds. Then I added high pass filters as well. Sounds quite nice now but still the dash speaker volume is a bit high. Just tired of screwing around with it. My big dumb fingers hate getting at those forward screws.
Actually with good front door 3 ways I pretty much dont need dash speakers. Unless I have passenger legs blocking them.

 

[GIJoe2010]

I just did this mod about an hour ago and the sound is beautiful now. I still biased my balance one notch to the rear and changed the EQ settings, but I can crank it up and the fronts aren’t overpowering any more. I have a nice balance of sound throughout the truck. Thanks for the great idea and easy to follow write up.

 

[Matts175]

Thanks for taking the time to post this. I just ordered some Kicker dash speakers, Metra adapters and the resistors.

 

[PowrRam]

Thanks for the great idea and easy to follow write up.

Thanks for taking the time to post this. I just ordered some Kicker dash speakers, Metra adapters and the resistors.

You're welcome.



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[Matts175]

Got this done today. WOW!!! The Kicker 3.5" sound great up there. I had to turn my treble down to +1. It was on +7 with the stock ones. Just have to pull the door panels off now and get my new 6x9s in. I'd do it right now, but I'm waiting for my muffler guy to call me and tell me he's ready to remove this "hot water tank" and put my Magnaflow on.

 

[QwikKota]

Has anyone added bass blockers in conjunction with the resistors to keep unwanted low frequencies from the dash speakers? If so which uF capacitor did you go with and will it effect the door speakers since the wiring is in parallel?

 

[JEFFREY HERBERT]

Great post I upgraded my dash and 6x9 and was like wtf.
Dash speakers are loud as hell.
I shame myself as I have a background in electronics.
Never looked at the 8ohm screen printing on bottom of dash speaker.
Resistors on the way will have them in soon.
Thanks

 

[Matts175]

Great post I upgraded my dash and 6x9 and was like wtf.
Dash speakers are loud as hell.
I shame myself as I have a background in electronics.
Never looked at the 8ohm screen printing on bottom of dash speaker.
Resistors on the way will have them in soon.
Thanks

Yeah. You'll like it once the resistors are in place.

 

[JEFFREY HERBERT]

Just put them in this morning now it all sounds so much better. Mine were not as pretty as yours though.

 

[duckman631]

View attachment 170640 Just put them in this morning now it all sounds so much better. Mine were not as pretty as yours though.

Why did you go with 20w instead of 10w resistors?

 

[JEFFREY HERBERT]

No reason in general they were actually cheaper then the 10w ones when I looked on amazon.
My Kenwood head unit won’t put out that much power Regardless.

 

[staying_tuned]

No reason in general they were actually cheaper then the 10w ones when I looked on amazon.
My Kenwood head unit won’t put out that much power Regardless.

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!