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A venerable reputation alone won't do much in our laboratory, of course, but performance will.

Turns out, the J33i put up a quality fight. Like the very similar J22i model, these headphones earned great marks in the lab, impressing us with factors like portability, noise cancellation, and build quality. Most listeners will be more than pleased with this soundscape, especially anyone with a bit of bass lust.

More practical than fashionable

The J33i in-ears certainly aren't the flashiest set in town, but the design is still quite attractive and practical.

Press the remote's middle button for a moment to summon Siri.

Listeners will get plenty of use from the three-button remote/mic, for instance: Without reaching for your pockets, you can easily skip that song you're sick of, increase your volume, or answer your phone.

There are actually two different versions of these headphones—the J33i for iPhones, and the J33a for Androids. If you own the first, you can press the remote's middle button for a moment to summon Siri. If you own an Android, the J33a offers a standard universal remote—no volume control for you.

As for the sturdy cable, it sports a flat contour that reduces tangles. Tack on the little shirt clip to avoid unwanted tug and you're almost in business.

Be sure to peruse the four different speaker covers.

Before you get to listening, though, peruse the four different speaker covers. One is made of foam, which users compress and insert. After a moment, the foam expands again for a more customized fit. If those are too big or too small, there are three other sizes of same-shaped silicone sleeves to choose from, too. I wish there were more shapes, and maybe one even-smaller size, but this is still a very nice selection that should suit most.

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If you need to commute with the J33is, just tuck them into their palm-sized, zippered carry case to keep them from harm. The materials are all quite nice, and the jacks and other vulnerable points are fairly well protected, but a carry case will always help preserve your headphones from unnecessary wear and tear. Rounding out the nice design is the fact that the 1/8 plug is gold-plated—always an appreciated touch.

Trendy quality to please most, with a minor blemish or two

With the sole exception of noise cancellation, the J33is perform almost the same as their sibling, the J22i. So right off the bat, unless peace and quiet is a big part of what you're after in a set of in-ears, definitely take a look at the other model—maybe you'll save a buck, maybe not, prices vary online.

There's plenty of emphasis on the low end, but big focus on middle and high notes too.

That said, in terms of their actual audio quality, the J33is are likely to please many. Refined ears won't take kindly to a bass range as big and loud as this one, but most listeners these days want exactly that. These JBLs put plenty of volume emphasis on the low end, so that bass really booms, but there is also big focus on middle and high notes.

Some of the highest notes are _so_ prominent that you'll likely find yourself turning down the volume because of slightly abrasive cymbal crashes and the like.

The result is a very bass-driven sound profile supported by prevalent middle and high notes. However bassy a song may be, you'll still hear chimes, vocals, snares, and violin strings, no problem.

In fact, some of the highest notes are so prominent that you'll likely find yourself turning down the volume because of slightly abrasive cymbal crashes and the like. Occasionally, the "s" sounds on vocals were enough to make me flinch and tick down my volume. JBL could have gone a bit easier there.

As to the rest, distortion-free listening is a major perk. From the lowest to the highest notes, music goes unhampered by clipped harmonics or added junk—well done JBL.

Sibling rivalry

At the end of the day, the J33i has a starting price of $79 while its relative, the J22i, starts at $59. What's the difference? Both do a great job quieting the noises around you, but the J33i does a slightly better job, thanks to the included foam tips.

And like its relative, there isn't much to complain about when it comes to the J33i. Higher notes can really hiss at times, which may have you turning the volume down even when you don't want to, but otherwise things sound great. Bass is quite eminent, but doesn't overpower delicate middle and high notes. On top of that, everything is distortion-free. Add on great design, portability, and quality parts—what's to complain about?

Maybe the better question is, what else is out there? Competition, that's what. If you're a determined bargain hunter, you could get the same great sound for a much lower price by compromising build quality, for instance. Yet for all that, the J33i's performance and build quality are top notch—and sale prices of around $40 online make the deal that much sweeter.

A lesser product might break under the pressure of a slew of tests, a laboratory, and a stone-cold robot, but the J33i in-ears came out mostly unscathed. From frequency response, to isolation, to distortion testing, we continually noted positive scores. Trials did reveal a few drawbacks, like some mild tracking errors, but nothing too severe on the whole.

Crowd-pleasing balance

As with most of the consumer audio products we test, the J33i's frequency response handles a signal much like an equal loudness curve—meaning it equalizes frequencies in volume for the human ear. Audiophiles prefer a flat response, they'd just as soon achieve that balance themselves, but the J33i is no studio product—so these are some fine results.


The JBL J33i balances sound nicely, with a firm foundation of prominent bass, but plenty of volume for middle and high notes, as well.

From the sub-bass range all the way up through the highest notes, the J33i strikes a mostly proper balance of emphasis throughout. The curve on the chart may look erratic to you, but this response actually means your audio will sound balanced in practice. The low end is heavily emphasized, treating listeners to big, pounding bass tones—but finer, higher pitches like female vocals, chimes, or cymbals will be easy to hear, too. The highest notes are in fact a bit over-emphatic, clanging out so abrasively that you may find yourself lowering the volume to spare you ears.

A+ performance

The J33i is a total ace when it comes to distortion. The sub-bass range, even on expensive products, are often wrought with clipped harmonics and other garbage, but these in-ears keep distortion measure to below 3% throughout the entire range. These are excellent results.


The J33i aced its distortion test, keeping levels to below 3% across the board.

If you increase volume up past 112.46dB, these measurements will jump to more than 3% though—all the more reason to practice safe listening and stick with volumes no higher than 100dB.

No severe errors, but results aren't flawless

Tracking tests measure the balance of volume between left and right speakers. Is music much louder on one side than another? Hope not.


Volume does spike in the J33i's right speaker around 2kHz, but most will never hear this mild error.

Happily, the JBL J33i is mostly balanced from left to right. Certain high middle notes are notably louder in the right channel at times, but the error doesn't span the entirety of said range—most listeners will never even notice it. We've noted better tracking results before, but there is nothing fatal here.

Foam tips for the win

The J33i in-ears sit right inside your ear canals, so of course they do a great job blocking outside noise. But they also ship with foam tips, and that means noise cancellation will be extra-great.


If you need to block outside noise, the J33i is a great bet; it halves low-end noise, and batters high-pitched sounds to 1/32.

Using the foam tips, outside noise of the bassy variety, such as grumbling engines or baritone voices, are hushed to about half their volume. Things just get better the higher the pitch: Mid-tone sounds get cut to anywhere from 1/4 to 1/8, and very high-pitched bothers are hammered down to as much as 1/32 their original volume.

Looking Further...

The J33i in-ears have no issues with unwanted echoing, as this impulse chart shows.

Meet the tester

Virginia Barry

Virginia Barry

Former Managing Editor


Virginia is a former Managing Editor at Reviewed.com. She has a background in English and journalism. Away from the office, Virginia passes time with dusty books & house cats.

See all of Virginia Barry's reviews

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We use standardized and scientific testing methods to scrutinize every product and provide you with objectively accurate results. If you’ve found different results in your own research, email us and we’ll compare notes. If it looks substantial, we’ll gladly re-test a product to try and reproduce these results. After all, peer reviews are a critical part of any scientific process.

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