JBL GTO638 | 6.5-Inch 3-Way Speakers| Review

Whether you are hitting the road on your own or have got someone by your side, you can definitely agree to the fact that music is the best companion you could have. What if I told you I had just the perfect speaker replacement for your factory installed unit?

Well, I know this may sound somehow too good to be true but it actually is; today, we’ll be taking a look at the JBL GTO638 6.5-Inch 3-Way Speakers.

Before we move on to take a look at what makes this set of components as good as it is, you should know that when it comes to car speakers, there’s quite a lot to consider. It’s all about narrowing down your options to getting something that’ll be able to offer you exactly what you want.

That being said, how about we move on to the main agenda? Let’s get started with our review, shall we?

Moving on to the main agenda, it’s time to take a look at the in-depth review of the

The Woofer- definitely the Best bass

The woofer and the tweeters are basically what we should expect from a full-range car speaker whether it’s a two-way or a 3-way car speaker, it just has to have these two.

For our JBL GTO638, you’ll be getting a 3-way speaker in your vehicle which simply means that the performance will be above average but for now, let’s take a look at the woofer alone, shall we?

listen The Quality Sound

Another One!

You’ll be getting the Patented Plus One woofer cone. This type of cone is quite popular with the JBL component speakers and truth be told, it will give you a kick for your buck. The Plus One woofer cone has got a greater surface area as compared to the other woofer cones and in addition to this, it’s constructed from propylene. As a matter of fact, as compared to most of the other speakers, the plus one woofer cone is about 30% larger in size

In a nutshell, the larger the surface area on a woofer cone means that it is going to move more air which in turn leads to the delivery of a better bass as far as clarity and accuracy are concerned.

As for the polypropylene, you should know that the best speaker cones for the best bass are normally constructed from the rigid and flexible material. This is usually done to increase the sensitivity of the speakers and at the same time don’t compromise on the quality. The high sensitivity and outstanding rigidity ensure that you get an outstanding bass in overall.

Besides the woofer cone, something else that greatly influences the bass quality is the type of surround you have on your woofer which takes us to the next point.

Edge-Driven, Mylar-Titanium Super Tweeter

Whereas some music genres lean more towards the bass, some lean more towards the tweeters. Considering that your taste in music is entirely a personal opinion, JBL strives to ensure that the tweeters are just as good in playing their role as are the woofers.

That being said, let’s have a look at what theJBL GTO638 have for us…

Right out of the box, you’ll be getting a pair of the JBL GTO638 speakers. Each of these speakers is a 3-way and included in the design is an Edge-Driven, Mylar-Titanium Super Tweeter.

Unlike the normal tweeters you are used to, these tweeters will be quite the upgrade; first, they come with a large voice coil similar to what you will get in home audio systems. The benefit of having a Mylar and titanium blend is that you get both lightweight and strength all in one.

Besides just being light and strong, the larger the voice coil is the greater the surface area and the better the heat dissipation capabilities it’s got. With this, the voice coil is able to increase power handling on the super tweeters and simultaneously reduce distortion at high output levels.

The design on these tweeters is also meant to create a more seamless integration with the woofer and more so, it is adjustable. You can, therefore, modify them so as to optimize the sound and get crystal-clear and extended high frequencies.

Edge-driven Mylar titanium tweeter

Whereas the super tweeter functions to handle the extremely high frequencies, the edge-driven Mylar titanium tweeter on the JBL GTO638 simply handles the high frequencies.

Here’s what makes it a choice worth your money…

With the addition of this driver in the component JBL speaker, rich sound is delivered via the midrange frequencies which, as we all know is where most vocals in the music are found.

With the addition of extra detail in the mid-range coupled up with the super tweeter’s high frequencies and the low frequencies of the woofer, this qualifies as an audiophile's number one speaker. As a matter of fact, it indeed is worthy of being used for home entertainment as well

The addition of a built-in crossover network.

Well, here’s something you don’t see every day- a built in crossover in a coaxial speaker system. One of the main reasons as to why people do not settle for the coaxial speakers as a suitable upgrade to the factory installed units is the frequency overlap in the drivers.

Whereas some speakers incorporate bass blockers so as to prevent the bass from going to the tweeter, this one does so much more.

By incorporating the use of a built-in crossover network that has got advanced high and low pass filters, the JBL GTO638 is able to create a smooth transition between the woofer and the tweeters. The end result of this effect is mid-range vocals that are so natural you can hardly tell them apart from the original sound.

Rubber surround- get the best flexibility.

Having an outstanding woofer cone with a poor-quality surround would mean that the cone will not be able to reach its full potential.

In the JBL GTO638, the surround is made of rubber. As compared to most of the other surround materials, a rubber surround might just be the perfect choice if you want the biggest kick for your buck. This does not restrict the cone movement in any way and by doing so, the cone moves freely and achieves its optimal potential.

Something else that makes rubber far much better than most other surround materials is that it’s quite durable. Considering that the speakers tend to be heated up at times which may lead to the bass being flawed, rubber tends to take care of this since it is not affected by extreme temperatures. Besides just extreme temperatures, rubber is also not affected by moisture.

Outstanding durability- listen loud at all times.

We can both agree on the fact that the last thing you'll want to worry about is the quality of your speakers. When it comes down to this, you should know that each JBL speaker released in the market is passed through as much as 500 hours of environmental testing inclusive of which is the JBL GTO638.

This set of component car speakers is exposed to temperatures fluctuating between -35 degrees Celsius and +90 degrees Celsius and; more so, there is as much as 90% humidity exposure for more than 200 hours.

The speakers are also exposed to UV light for more than 150 hours so as to stimulate the mounting location on the vehicle’s deck. to see to it that you’ll only be getting the best from these speakers, they are passed through vibration testing possibly to simulate their operation in a moving vehicle.

In a nutshell, JBL has put a lot of time and resources into this set of coaxial car speakers to ensure that they won’t disappoint you- this should be enough reason to put your money on the JBL GTO638.

Easy installation.

Even for someone who’s done a speaker installation in the past, they can agree that it’s not an easy task since every vehicle is different and so is the physical construction of the speakers.

Watch The Unboxing JBL GT0638 speakers

What if I told you that you could actually do the installation of the JBL GTO638 on your own? I know, this sounds too good to true but here’s what makes this car speaker one of the best and user-friendly speakers in the market.

Since most OEM speakers measure 6 ½ inches, this car speaker does have this measurement as well. If your vehicle happens to have a 6 ½ installation location, you can easily be able to replace your stock speakers without the use of any special tools. You’ll also not have to worry about making any modifications.

Right out of the box, you’ll get quite some installation gear that’ll definitely make things easy for you. included with the speakers are mounting brackets and grilles as well as a buffer for the bracket/grille. You’ll also be getting 16 screws to make the installation easier.


To make the installation much easier, the JBL GTO638 employ the use of the patented intermount III mounting system. Normally, depending on the type of vehicle you have, the common factory built 6 ½ inch location can vary in size to about 6 ¾ inches. To take care of this slight variation, this set of speakers come with installation rings included. This makes replacing even an older set of aftermarket speakers quite easy.

Something to have in mind…

Even though you can install the speaker in a number of places, the doors seem to give the best results in creating a good soundstage. When installing them on your doors, ensure that the window is not obstructed in any way since the magnet is quite large. Most preferably, you should probably take your measurements to the last centimeter so as not to damage the speakers or any mechanisms in the door.

True 4-ohm Topology

The impedance rating is one of the important features in speaker operation. Before we move on to looking at what the JBL GTO638 have in store for us, let’s take a look at what impedance really does.

Speaker impedance normally determines how much power will be able to reach the speakers from the radio head unit. Normally, the lower the impedance rating the greater the amount of power gets to the speakers. Simply put, low impedance voice coils are able to extract more power from your amp or head unit as compared to the high impedance coils.

In the JBL GTO638, the impedance coil used is lower than the 4-ohm coil which is considered as being of outstanding performance, now, think of how much you’ll get from the 2-ohms in these speakers.

The reason the 2-oh load is better is that the speakers will be able to extract as much power as possible from amps that are designed to drive loads that are 4 ohms or less.

Most factory-installed sound systems include 2-ohm speakers and amps made to drive the 2-ohm loads.Replacing them with anything more than this reduces the amps output power. Taking this into account, getting this set of JBL speakers ensures that you get the most powerful performance from the speakers.

Power Handling

For the best sound quality, it’s important that the speaker’s power handling capabilities be as good as possible. When it comes to power handling, you’ll need to pay attention to the RMS. This is basically the continuous wattage that the speaker runs on without getting damaged.

For our set of JBL GTO638, the RMS is 60 watts. This may not seem like a lot but considering the impedance rating on the set of speakers, you’ll definitely have your mind blown. The speakers will be able to extract as much power as possible which means that the bass will not be compromised and the same goes for the mid and the high frequencies.

As for the peak, the rule of thumb in most cases is that this is double the amount of RMS but it doesn’t necessarily have to be the case which is why you’ll get 180 watts for these car speakers.

The peak, unlike the RMS, pushes the speakers beyond its limits. You, however, should not substitute the peak for the RMS since if the speakers operate beyond the peak for too long, you could end up with a distorted sound.

This may need you to go spend on the repair or even worse, you may be needed to make a full replacement of your speakers which can be quite frustrating.

Sensitivity- louder & Better

The power and impedance are not enough to give you an outstanding sound which is why you’ve got the impedance rating.

The impedance and the power handling normally work hand in hand in the sense that the higher the impedance is, the better and louder sound you’ll get. The benefit of having the high impedance on a speaker is that with the high sensitivity, the speaker gets to produce louder and clearer sound while at the same time making use of the least amount of power.

The recommended rating is normally 88dB but in our case, you get an outstanding 94 decibels. This sees to it that the sound is loud without any lags, distortions or being too ear piercing.

Coupled up with the impedance and power handling, you'll also be able to make use of as much power as possible. This, in the long run, gets you the most from this 3-way coaxial speaker system- it's definitely going to give you a bang for your money.


  • Built-in crossover network to isolate the high frequencies from the lows to give a lifelike experience.
  • The plus one woofer cone has a greater surface area for a better bass response.
  • With the rubber surround, you get both durability and utmost flexibility from the woofer.
  • Comes with mounting brackets, grilles, and screws to make installation easier.


  • you may have to do some modifications on the fit just in case it’s a hassle to have them in place.

Frequently asked questions (FAQs)

Q: what is the mounting depth of the speakers?

A: this is 2 1/16 inches

Q: what is the impedance of the speakers

A: the rating is 2 ohms as indicated in the package

Q: how's the bass in this pair?

A: the bass is good; you can always add a subwoofer if you want more

Final Verdict

As far as quality is concerned, the JBL GTO638 car speakers are definitely worth every penny. From the construction design to the installation procedure and the performance, this pair might just be the perfect upgrade to your stock installed speakers.

For an even better performance, I recommend that you consider doing an all-around upgrade on your sound system when you decide to get this pair. This way, you can then match the speaker to a head unit that'll ensure the full potential of this set is achieved.

Proper maintenance is also important. Be sure to observe the RMS threshold. At the same time, you should make sure the mounting location does not compromise the safety or performance of the speakers.


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