DIY 3.5" JL Audio dash speaker upgrade - Wow!! (detailed how-to)

57HotrodVW

New member
After seeing a few posts about speaker upgrades, I decided to do one to the dash speakers in my '18 TRD Pro, and thought I'd share. In short, this lower cost, relatively easy upgrade is well worth it, and makes a huge difference in sound quality!

Rather than just going with a popular tweeter upgrade (aka, the Subaru/Kicker plug and play tweeters), I decided to go with 3.5" coaxial speakers from JL Audio - the C2-350x models. These full range speakers cost ~$80, and I bought mine at Amazon - https://www.amazon.com/dp/B001UDNXOQ

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I also purchased a pair of tweeter wiring harness adapters, so I didn't have to cut the factory wiring (others have taken apart the stock speakers to make an adapter plug of sorts, or kind of "jumpered" the male portion of the 4 wire factory plug). I got the adapters from Taco Tunes - https://tacotunes.com/shop/toyota-4...eter-speaker-wiring-harness-adapter-connector

To limit lower frequency sounds from being played by these speakers, and prevent "clipping" at higher volumes, I also bought a pair of 133 microfarad capacitors (aka "bass blockers"), to cut sounds below 300 Hz - https://www.amazon.com/dp/B017AJ5ECW

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The construction differences between the OEM and JL Audio speakers are notable:

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Removal of the stock speakers is easy. I started by using a plastic trim tool (part of a set like the ones at https://www.amazon.com/dp/B00ZRJCYQ2), and gently prying from the center/rear-most portion of the speaker grills to "pop" the two clips that hold them in.

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From there, a small ratchet, extension, and 10mm socket was used to remove the two hex head screws (with Phillips patterns in the top, as highlighted in red in the image below). After these screws have been removed, the speaker mount and speaker can be lifted out as an assembly. Push the tab on one side of speaker plug/harness to release it from the blue "cap" of the stock speaker, and disconnect the speaker assembly (the second image below is one where the factory mount is still in place, but I suggest removing the speaker and bracket as an assemblly, via the Phillips head screws)

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The Taco Tunes adapter harnesses make wiring a pretty simple affair. Because of the way that the door speakers are wired with the dash speakers, there are four wires in the factory dash speaker harness/plug. To mimic the same using the Taco Tunes adapter harnesses, make four wires into two -- red and white wires go together for the positive side, and black and white/black go together for the negative side. I cut the long wires of the Taco Tunes adapter harnesses down to about six inches, to reduce bulk when installed under the dash.

The capacitor is connected inline, on the positive side wire. Joints were soldered and finished with heat shrink tubing.

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Next, I fabricated some mounting tabs out of 1" wide x 1/8" thick aluminum bar stock, which can be purchased at most hardware or home improvement stores. These didn't have to have as complex of a shape as I made them, and a simple rectangle would have worked, but mine are shaped like they are due to earlier plans changing a bit, and not wanting to re-make the brackets.

Rectangular tabs would be 1.75" long and .75" wide. Two holes are drilled in the tab, 1 5/16" apart. The smaller one at the top (which the Phillips head screw will go into) was drilled using a 5/32" bit, and the larger one was drilled with a 3/16" bit.

The hardware used to attach the tabs to the speakers is 8-32 button head machine screws that are 3/4" long, with matching nuts and washers. I put one washer under the screw head, two washers between the aluminum tab and speaker (for spacing), and one washer under the aluminum tab.

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The Phillips head screw can be used to make threads in the smaller/top hole. It takes a little force to start the screw in the hole, but do this, tighten until snug, and then remove the screw. It is much easier to do this outside of the vehicle, than inside when mounting the tab/speakers in the dash.

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This photo depicts what the tab looks like when mounted on the speaker. The Phillips screw was removed prior to putting the speaker in the dash. I put blue thread locker (aka Loctite) on the button head hardware, and tightened it fairly well, but just loose enough so that I could move/align the tab with the speaker in the dash hole.

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When installing the speakers in the dash, the side of the speaker without the "tab" attached will be fastened using the Phillips head screw and existing "spring nut" that is already installed on the dash plastic. On the opposite side, you'll need to remove the "spring nut" by simply sliding it off the dash plastic (don't drop it into the dash hole, or it may be hard to retrieve. The photo below shows one of the spring nuts after it has been removed.

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After plugging the factory speaker wiring harness to the speaker, and tucking in the wires, the speaker can be carefully dropped into the dash hole. On the driver's side, put the speaker "ear" on top of the spring nut that is on the left, and loosely fasten it with one of the Phillips head screws. The fabricated "tab" on the other side of the speaker goes under the dash plastic where the spring nut previously was. Insert the Phillips screw through the top of the dash, and tighten it into the tab below, as depicted in the images below. Don't overtighten the Phillips screws on either side of the speaker, and it is a good idea to put some thread locker on them.

The installation of the passenger side speaker is similar, but it is a tighter fit due to the ductwork for the defroster vent below the speaker hole. It took some wiggling and pushing down to get the speaker into position, and clearing the sheet metal closest to the windshield.

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The OEM speaker grills have a ring on the bottom side that meets up with foam that is on top of the factory dash speakers. I used an angle grinder and sanding disc to carefully sand away/remove both rings, so that the back of the grills was essentially flat, and no speaker interference would occur.

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Snap the speaker grills back into place, and the installation is done.

Now crank up some tunes, and enjoy the much improved sounds, as well as the satisfaction that you did it yourself!!
 
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Nice writeup, I almost bought these exact 3.5's but settled for some JBL's that were a bit cheaper with great reviews. I got the same TacoTunes wiring harnesses and will be installing mine tomorrow. Can't wait!
 
Nice writeup, I almost bought these exact 3.5's but settled for some JBL's that were a bit cheaper with great reviews. I got the same TacoTunes wiring harnesses and will be installing mine tomorrow. Can't wait!

Thanks! I hope your install goes easily.

If you don't already have the capacitors, and need some locally, Best Buy carries them, as should any car audio shop.

https://www.bestbuy.com/site/truconnex-bass-blockers-set-of-4/6814616.p?skuId=6814616

Also, make sure that your wiring hardness adapters from Taco Tunes have four wires each. One of the first pair that I got only had three wires in it :mad:
 
Thanks! I hope your install goes easily.

If you don't already have the capacitors, and need some locally, Best Buy carries them, as should any car audio shop.

https://www.bestbuy.com/site/truconnex-bass-blockers-set-of-4/6814616.p?skuId=6814616

Also, make sure that your wiring hardness adapters from Taco Tunes have four wires each. One of the first pair that I got only had three wires in it :mad:

I got capacitors already, but good looking out. And I already inspected the wiring harnesses, pretty sure they have 4 on each, at least I hope they do!
 
Finally got time to do this mod with my new set of JBL Club 3.5's from Crutchfield. I also grabbed some bass blockers on Amazon

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The wiring for the tweeters is different than my 4th gens, so I had to get new 4 wire wiring harnesses from TacoTunes to do this install, I've had them laying around for the last year and finally put them to use. Since the speakers are wired in parallel I had to splice the 2 positive and negative wires together

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Here's a before of the stock tweeter paper cone garbage, these were the only stock speakers left in my truck

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And here's a little side by side

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So once I got all the wires soldered up, I threw on the foam dampening material, even though they barely touch any metal other than the mounting brackets.

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I had gotten a spare set of twetter mounting brackets from a member on here so I cut those up to make the mounting easier since the speaker basket was so large and to keep the stock tweeters completely intact

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So I mounted them the same style as the tweeters

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And here's the driver's side all installed, the driver's side was super easy to install because it has plenty of room underneath...

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The passenger side has air ducts directly below it and is much tighter, I eneded up having to take the left bracket back out and trim it down further with some tin snips, and tuck the wiring down in the back in order to get it to fit correctly

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But then I got it to bolt right in, and voila!

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I also trimmed the speaker grills down

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Then I reinstalled the speaker grills, and cranked up the tunes! They sound SO much better than stock, the stock tweeters are garbage and were killing me for quite a while. So glad I finally got this mod done

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Are you running the JL C2-350x off the factory amp? If so, did you change the door speakers as well?
 
I am watching all the speaker changes using the factory head unit. Is it powerful enough to make a difference in a 2018 sr5 regular or are better quality speakers making the difference?
 
I am watching all the speaker changes using the factory head unit. Is it powerful enough to make a difference in a 2018 sr5 regular or are better quality speakers making the difference?

I'm running all my speakers except my sub off of the factory unit and just adding quality speakers with real magnets made a world of difference to me. I have a $500 4 channel amp sitting in my closet but don't feel the need to use it since the speaker upgrades improved the sound so much
 
I started with those JBL Club 3020 and definitely an improvement over factory.

But then I switched to Hertz 87.3 and with higher sensitivity (92 vs. 89) they play about 3 dB louder than the JBL Club 3020 with factory power. (Every bit counts if you are not amping). I also preferred the sound of the Hertz over the JBL.

Mod was the same as posts above, but I also added some acoustic fill into the empty space around the speaker as the aftermarket speakers are not "sealed" to the speaker cover like the factories. Not much of a seal, but the foam on the factory speakers match the plastic ring on the cover. Not sure how much of an impact the acoustic fill has but makes sense to me.
 
I'm running all my speakers except my sub off of the factory unit and just adding quality speakers with real magnets made a world of difference to me. I have a $500 4 channel amp sitting in my closet but don't feel the need to use it since the speaker upgrades improved the sound so much

Since I dont really off road but am an audiophile, I am thinking this may take priority for just a speaker change. I am halfway satisfied with the sound now. I would hate yo hear an upgraded speaker unit, minus sub.
 
Are you running the JL C2-350x off the factory amp? If so, did you change the door speakers as well?

I am using the factory head unit with these, and they sound great all the way up to near full volume.

IMO, the stock system has a fair amount of bass, but sounds "muddy" up front, due to a lack of highs.

Adding the 3.5" coaxial speakers added the missing highs with their woofers, along with extra mids.

I'm very happy with the sound now, especially given the price/effort required to improve it. The only thing that I might change in the future would be to add a powered subwoofer under one of the front seats. I've heard good things about the Kicker 11HS8 powered sub from other 4R owners on the forums -- https://www.crutchfield.com/p_20611HS8/Kicker-11HS8.html
 
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re: Speaker Impedance

Cool install and write-ups from both guys above (one doing the JL the other the JBL speakers), thanks for the awesome details.

One thing confuses me though....the JL speakers used above were 4ohm speakers. The JBL speakers were 3ohm. In other audio threads I've read guys are using 2ohm Infinity Kappas??? Something is not right. The speaker impedance should be matched to A) what the stock speaker was and/or B) what the factory deck is designed to drive at. I'm a little surprised that everyone in these threads is claiming such great results with no issues with such a varied use of speaker resistances. Some decks must be running quite hot as a result I would think.

As I understand it, since the dash speakers are wired in with the door speakers, we should be using a 2 ohm speaker in this case (or as close to it as possible). Am I correct, or is the Toyota deck versatile enough where is doesn't really matter?

Thanks.
 
...the JL speakers used above were 4ohm speakers. The JBL speakers were 3ohm. In other audio threads I've read guys are using 2ohm Infinity Kappas??? Something is not right. The speaker impedance should be matched to A) what the stock speaker was and/or B) what the factory deck is designed to drive at. I'm a little surprised that everyone in these threads is claiming such great results with no issues with such a varied use of speaker resistances. Some decks must be running quite hot as a result I would think.

As I understand it, since the dash speakers are wired in with the door speakers, we should be using a 2 ohm speaker in this case (or as close to it as possible). Am I correct, or is the Toyota deck versatile enough where is doesn't really matter?

Thanks.

Speakers of lower resistance (ohms) require less power to drive them. Speakers don't have to be of matching resistance, but total resistance (based on Ohm's Law) varies with how they are wired - i.e., series versus parallel. You can find some related info in the thread at Ohm's Law in Car Audio
 
Speakers of lower resistance (ohms) require less power to drive them. Speakers don't have to be of matching resistance, but total resistance (based on Ohm's Law) varies with how they are wired - i.e., series versus parallel. You can find some related info in the thread at Ohm's Law in Car Audio

I agree with using Ohms law to calculate the load. It is important to know the load on the amp/headunit. It is also helpful to know the specs of the amplifier/headunit. Not all amplifiers are 1 ohm stable. Some probably aren't 2 ohm stable.

"As the ohms drop, the amplifier will unleash more power, but with less control. This is an important aspect to remember. Failing to understand this concept is probably the main cause of self installed amplifiers shutting down and going into protection mode."
From this article: 2 Ohm, 4 Ohm, 1 Ohm, what's the difference? - Car Stereo Reviews & News + Tuning, Wiring, How to Guide's
 
Cool install and write-ups from both guys above (one doing the JL the other the JBL speakers), thanks for the awesome details.

One thing confuses me though....the JL speakers used above were 4ohm speakers. The JBL speakers were 3ohm. In other audio threads I've read guys are using 2ohm Infinity Kappas??? Something is not right. The speaker impedance should be matched to A) what the stock speaker was and/or B) what the factory deck is designed to drive at. I'm a little surprised that everyone in these threads is claiming such great results with no issues with such a varied use of speaker resistances. Some decks must be running quite hot as a result I would think.

As I understand it, since the dash speakers are wired in with the door speakers, we should be using a 2 ohm speaker in this case (or as close to it as possible). Am I correct, or is the Toyota deck versatile enough where is doesn't really matter?

Thanks.
As a bass player with my eden amp you could use 2 ohm bass cabs. If you used an 8 ohm cab it didn't affect my amp except for volume. Lower ohms will put out more volume. If you run two 8 ohm cabs together it changes the ohm to 4 for the cab. IMO, the only affect you may have by using different ohms would be variable volumes from different speakers when setting volume from the head unit.

Maybe I'm wrong but in my bass playing head that makes since.
 
Great job and write ups! Thanks for sharing! JL, blockers, and adapters ordered. It will probably be a couple of weeks before I can get to it.

Anybody have some stock dash tweeter mounts that they don't need? I will buy them.
 
Has anybody done this mod on a stock JBL system? I have a blow speaker that needs to be replaced but definitely don't want to go with factory. Thoughts?
 

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