Logitech UE 600 In-Ear Monitor

Logitech UE 600 ($100)
A few months ago we tested Logitech UE's new in-ear flagship, the UE 900---a top-tier, quad-driver earphone with very impressive sound quality. Continuing the budget theme of my recent reviews, I thought the company's cheapest armature-based model was worth taking a look at as well.

Like all of the higher-end Ultimate Ears models, the UE 600 measures well---very well for something based around a single balanced armature transducer. It sounds good, too, especially considering that the earphone has been around for the better part of four years.

Originally known as the Ultimate Ears Super.Fi 5vi, and later the Ultimate Ears 600vi, the current Logitech UE 600 comes with a remote and microphone and retails right around $100. The remote is a 3-button unit designed for iPhones and other Apple devices. The microphone will also work with many non-Apple smartphones, though the volume control will not. It seems Logitech has dropped the remote-less version of the UE 600 completely with the latest revision---a nod to the growing number of smartphone users. Those who prefer vanilla stereo earphones will now have to step up to the UE 700 or UE 900.

The UE 600 is based around a single top-firing balanced armature transducer. The vertically-mounted driver gives the earphone its unique shape, allowing the main body to be placed perpendicular to the nozzle. The construction is plastic but the smooth chrome finish gives the UE 600 a polished, upscale look. Color coding of the nozzles makes it easier to tell the left and right earpieces apart. The cable is identical to those found on the UE 350 and UE 700 models---soft and tangle-resistant, but lacking in strain relief at the 3.5mm plug. A protective hard shell carrying case is included to help keep the earphones intact.

The plastic build does keep the UE 600 lightweight and the long nozzle places the largest part of the housing comfortably outside the ear. To help with fitment further, the earphone ships with 5 sizes of silicone eartips and two pairs of Comply foam tips. Isolation from outside noise is above average, and made even better when the Comply foams are used. The position of the microphone indicates that the UE 600 should be worn with the cable looped up around the user's ear, though cable-down wear is also possible. Cable noise is very low.

Logitech UE
7600 Gateway Blvd.
Newark, CA 94560

Seth195208's picture

What kind of music do you listen to most? For a reviewer, I know the typical answer to that question is "A little bit of everything". But for headphones that measure accurately, I think it's important to listen mostly to well recorded small scale acoustic music, especially acoustic jazz, mainly because you can hear each individual acoustic instrument in its own acoustic space. Also, we all have a pretty good idea of what each of these instruments, from kick drum to cymbals and everything in between, sound like in real life. Electric and electronic  type instruments recorded in a complex studio environment kind of exist in their own subjective sonic reality. Headphones or earphones that have been tuned to deal with these subjective sonic realities are one thing (My Sony XBA3's for example). Objectively accurate (Measuring)  earphones like the UE600 seem to almost always prefer more purist style acoustic recordings and probably should be recommended for that type of thing. Most popular, over processed music just seems to be too harsh, zingy and forward sounding with the more accurate phones.

Would you agree? Or do you think I'm off base with this?

ljokerl's picture

I have no problem with this sentiment. Personally, I gravitate towards rock, blues, and jazz (more mainstream jazz, at least). I have a number of test albums in .wav format, which I listen to with every set of earphones I test. However, I do my reviews on a comparative basis, which I think eliminates some of the potential for bias. I will listen to a track over and over with several earphones to figure out where the set I’m testing fits in among others in its price range or performance bracket. Lucky I have that luxury – there would be more difficulty in trying to gauge the performance of an earphone objectively in a void.

On a similar note, sound signature preferences are usually tied into preferred genres so if you listen to mostly compressed-for-radioplay pop you probably won’t like (or be looking for) a set that pursues neutrality. Good thing there is no shortage of earphones that don’t measure flat – the market is saturated with them. The XBA-3 is one for sure, as is the pricier XBA-4 that I don’t really like all that much. This is also why reference-flat sets don’t always get great reviews out in the mainstream and why most entry-level sets tend to be tuned bassier or more v-shaped in signature.

Guitarist9273's picture

Does a reversed polarity usually correspond with any specific sound quality or characteristic issues in headphones?

I recall seeing that the HifiMan HE-400, HE-500, HE-6 and HE-5 also showed a reversed polarity in their measurements.

ljokerl's picture

Perhaps Tyll can share his views on this one - I don't have any experience with the HiFiMan sets referenced. 

Personally, I have tried to hear absolute polarity in a blind ABX using a pretty decent setup - an iBasso DAC feeding a Portaphile 627 and high-end custom monitors. I could not differentiate a track as recorded (not sure if polarity is always preserved through the recording process) from the same track with reversed polarity reliably (averaging ~50%, i.e. textbook randomness).

This is not to be confused with something that is out of phase (i.e. the polarity of only one channel reversed) - that I can hear very reliably.  

xnor's picture

It doesn't matter, as long as the left and right drivers are in phase.

Tyll Hertsens's picture

I've never heard any differences when both cans are out of polarity.  It's pretty easy to tell if only one is though---you completely loose the center image.

But since it's so easy to get right, it kind of sticks in my craw.

Seth195208's picture

It would be interesting to investigate whether left and right, out of phase headphones can be identified with listening alone. When listening with out of phase loudspeakers, destructive interference occurs before the sound reaches the ears, cancelling the bass and pulling the image to the left or right. It's a physical phenomenon. Physchoacoustically, I don't know if this cancelation effect can occur inside the head, even though it seems obvious that it would.

 Tyll, would you know off hand? 

ljokerl, have you heard this effect with actual headphones/ earphones?

ljokerl's picture

Yeah, absolutely. Out of phase earphones are very easy to hear - like Tyll said you lose the center image, everything sounds sort of vague and ethereal and seems to shift farther back. I don't know the physical cause for this - there is no destructive interference of sound waves with two out-of-phase in-ears, but it seems the brain still gets very confused. There are some cheap in-ears I've had that have been wired out of phase right out of the box.

xnor's picture

Interaural time differences. Especially at low frequencies, the brain uses phase differences between left/right to locate the sound source. Our hearing also expect a lot of crosstalk*, again especially at low frequencies. By supplying out of phase signals you're creating a completely unnatural experience.

*) that's why imho a lot of mixes sound weird on headphones without crossfeed

Seth195208's picture

I can now see how imaging can be effected in out of phase phones, based on the most dominant HRTF frequenies centered Between 1 and 5khz. As one ear canal is pressurizing at these important localization frequencies, the opposite ear is simultaneously being depressurized, which would completely destroy imaging specificity.

   Does that sound about right?



xnor's picture

It has little to do with where the hearing is the most sensitive.

At low frequencies the hearing uses mostly phase differences between left/right. At higher frequencies level differences become more important due to the short wavelength of those frequencies. So the confusion happens mostly below 2 kHz.

The wavelength of a 100 Hz wave is about 3.4m (11 feet). A 180° phase shift (the next closest thing to inversion) means the distance between your ears has to be about 1.7m (5.5 feet).

Seth195208's picture

Head related transfer function has nothing to do with image specificity? A 2khz wavelength is the width of a human head. A 4khz wavelength is half the width. So, your'e saying that primary stereo imaging cues don't occur in the range between those two frequencies? That they actually occur at wavelengths that are longer than the width of a human head? Really?

ultrabike's picture

I don't think xnor is implying that HRTF has nothing to do with image. In fact, I believe he is making a case for it in his previous posts. Here is a link to his crossfeed implementation (crossfeed attempts to mimic some of the effects of the HRTF):


What I understand form xnor's post is that relative phase differences (or issues) between the left and right channels of a headphone (or whole rig) impact soundstage the most if those differences happen bellow 2 kHz. This is something I didn't know and the point is much appreciated.

It is interesting that crossfeed and phase sensitivity seem to have a critical point at 2 kHz. Check Fig 1 of this link describing the effects on frequency response due to crossfeed in the Total BitHead:


Also, thanks ljokerl (ups! sorry for the typo) for a very well put together review!

xnor's picture

That's right.

Of course our hearing can both locate low (e.g. bass drum) and high (e.g. hi-hat) frequency sound sources. At around 2 kHz it's a mix of both relative, i.e. inter-channel, phase differences and level differences. The transition is smooth. There's also frequency response changes depending on the position of the sound source, but this is irrelevant for phase inversion.

A HRTF is just the response an ear receives from a sound source. If you have a pair of HRTFs, for example for a sound source 30° off-axis, you can see both the time and level differences. You can also see ear canal resonances, the acoustic mirror function of the pinna etc.

But coming back to phase inversion, what matters most is how our hearing interprets phase differences. And that happens to "work best" at low frequencies.

Seth195208's picture


My head was starting to spin. I will read the links to xnor's posts. The science of headphone based sound perception is fascinating.

Just for the record, it's ljokerl, not ljockerl. Tyll made a typo..  


yuriv's picture

I’m getting solid bass on mine. The UE600 has really low DC resistance, so if you’re using an amplifier with a capacitor-coupled output stage, there’ll be more roll-off in the bass response than almost anything else out there. On a Cowon or an older iPod, the response will be down a couple of dB by the time it reaches 40 Hz. Combine that with a dip at 3 kHz and a sharp drop-off after 10 kHz, and I can see how “mid-centric” could happen, especially with foam tips.

With enough series resistance, the UE600 will be fed by something much closer to a constant current source. The electrical response entering the IEM will follow the impedance-vs-frequency curve. This will pull up the voltage at 3 kHz by up to ~5 dB, depending on the added resistance, and this makes the response closer to the DF or ID target. Because the BA unit’s coil inductance dominates the impedance figure at high frequencies, we can also triple the relative voltage at the top octave. There’s your missing 10 dB of response above 10 kHz. Moreover, the amp will now see a higher-impedance load, so if it’s capacitor coupled, it’ll roll off the bass much more slowly than it did before. 

Also, the UE600 is one of the most sensitive IEM’s I’ve heard. On some players, you can hear the hiss on very quiet tracks when you plug it straight in. The added series resistance lets you crank up the player’s volume and improve the signal-to-noise ratio.

The Etymotic ER4 p-to-s adapter works pretty much the same way, but it makes the ER4p’s response at 2.5 kHz a little too high (for me). One can argue that the added resistance works better on the UE600. Channel balance issues aside, an easy way to make the IEM “see” the series resistance is to use a voltage-divider-type inline volume control like a Shure EAS650 or a Koss VC20. You can effectively dial in how much resistance you want. It’s like having a variable p-to-s adapter. Try this: set the player at maximum volume and the inline volume control at minimum. Then turn the control until the UE600 is loud enough. When I do this, what I hear is brighter and livelier than what I heard without the volume control. I certainly wouldn’t call it mid-centric now.

The big disadvantage to all of this is that it bumps up the resonance at 8-9 kHz too high. Maybe that can be fixed with an acoustic damper or different ear tips. But some people actually like the effect. On some kinds of music I can hear a fake sparkle that isn’t there when I listen to it on calibrated monitor speaker systems. Of course, you could just use an EQ. But the ones on iOS and Android don’t work system wide, like it does on Rockbox. BTW, here’s goldenears.net’s take on it:

Accudio - UE600

ljokerl's picture

Good info. The Cowon J3 does have some issues with such loads, as does the Touch 4G, but my Fiio E7 seems to do pretty well. If I remember correctly its output impedance is well under 1Ω. I don’t use the portable players for critical listening.

I have some fixed-impedance adapters but nothing variable, I don’t think. I tried a 68Ω one with the UE600 and it did things to the treble I did not like. If I can find a variable-impedance adapter that doesn’t introduce major imbalance like my old Shure one did, I’ll give it another try.

I did compare it to the Fischer SBA-03 (http://www.innerfidelity.com/content/dandy-meelecronics-a161p-and-fischer-audio-sb-03-measurements) which I would expect to exhibit similar bass roll-off to the UE600 but manages better deep bass and more impact.

All in all, I do like the UE 600 quite a bit and don’t think it has gotten the recognition it deserves in the 4+ years it’s been on the market. Especially surprising is that it wasn’t a hit early on when decent-sounding competition was much more scarce. That said, I like the SBA-03 / Etymotic HF5 better as far as $100 single armatures go. 

Seth195208's picture

  The newest touch has a .75 ohm output impedance.   It's about time they started catching on..

yuriv's picture

Yep, with a 16-ohm load, the Cowon J3 is already down -3.5 dB at 40 Hz. Its output impedance is much higher at low frequencies, hence the roll off. The UE600 has around 9 ohms DC resistance, so the roll off will be much more severe with it. The 4th-generation iPod Touch, on the other hand, has a direct-coupled output. There will be no roll off, like on old iPods like the iPod Video (5/5.5G). The Touch 4G actually handles a constant 16-ohm load well. It does have a higher output impedance that’s nearly constant with frequency--just under 4 ohms, which should be high enough to make it have an audibly higher treble response when driving the UE600 (up to +2.5 dB). So what you’re hearing from the Touch 4G is, effectively, bass that has been slightly shelved down, instead of rolled off. Arguably, the response is now more linear to a DF or ID target, especially with the foam tips.

The SBA-03 has a much higher minimum impedance than the UE600 (35 ohms according to Tyll’s measurements). So the J3’s coupling cap or the Touch 4G’s 3.7-ohm output impedance won’t have nearly as much effect. The iPod will play flat within 1 dB. So just plug it into either one.

I got my pair (the vi version) at least three years ago on clearance, but I haven’t used it for a long, long time. Your review and Tyll’s measurements got me to dig it out of storage. Whatever foam tips were with it are now worn out and don’t seal as well as a new pair of Comply TX400. My first impression upon hearing it again is that it’s a little bass heavy, even with the silicone tips. Compared to an RE0 or an ER4p matched at 1 kHz, the UE600’s response is stronger at 300 Hz, stronger still at 100 Hz, and doesn’t roll off until it’s well into the bottom octave. I hear a bassier presentation than what I get from any of my speaker systems or an HD600 (which already has around +3 dB of bass at 100 Hz).

What I’m hearing is more in line with the Accudio graph that I posted above. There, the green line decreases below 80 Hz because the Goldenears target curve has the “missing 6 dB” effect built in. The raw response will show the level higher in the bass.

So, could we be listening to two different versions of the same-model IEM? Logitech changed the connector, the cable, and the controls. Maybe they changed the sound too? If so, then Accudio will make the new version UE600 sound thin. GE will have to make a setting for the new revision.

Added series resistance works well with the sample that I have. The inline volume control increases the response above 1 kHz; it partially fills in the dip at 3 kHz, and it raises the level above 10 k. This also makes the UE600 sound less bassy. I measured an equivalent 32-33 ohms of series resistance with my favorite setting. So it comes as no surprise to me that 68 ohms doesn’t work for you--especially if the new revision really does have a different sound. I’ll have to try one out. Also an A161p when I get the chance.

ljokerl's picture

I must have misread the graph of the SBA-03... it looks to be well below 25 ohms below 100Hz assuming a linear scale.

I did stumble on two different versions of the UE 700 here: http://www.head-fi.org/t/599247/heads-up-two-versions-of-the-ue700. They looked different and sounded different, and no doubt would have measured different. 

I don't have an HD600 but the UE600 I have does not have the bass boost of my HD580, though it does not sound as flat as the ER4S to me. 

yuriv's picture

No, you didn’t misread anything. I did. I went with what Tyll wrote on the A161P review instead of reading the graph:

“Impedance is a fairly low 35 Ohms below 100hz, indicating that sources with high output impedance may have trouble maintaining the flat bass of the earphones.”

The 35 ohms is probably a typo, and should really be 15 ohms. In that case, you would get a bit of bass roll off on the J3. The Touch 4G would fare a little better: the treble goes up--but no more than 2 dB.

BTW, check this out:SE535 and UE600 frequency response

If you’re calling the SE535 mid centric, then I see where you’re coming from. The two-way SE535 has better distortion numbers, but worse performance in the time domain (depending on how you define “worse”).

Also, that’s an interesting read about the UE700.

ljokerl's picture

I did actually think the triple-driver Shures (both the old and new ones) have rather upfront mids - subjectively speaking, of couse. I know Tyll likes the SE535 and it is quite popular on Head-Fi but it's one of the few sets that never really did much for me.

Jazz Casual's picture

I appreciate your thorough, no-nonsense reviews ljokerl. Your Multi-IEM Review thread over at Head-Fi is a fantastic resource. Will you be reviewing the IE800?

Tyll Hertsens's picture

Jocker and I aren't sure if the sample we got is working properly, so we're trying to get another one.  I've passed some emails, and one should be coming soon.

ljokerl's picture

That was the plan for next month but it seems our (Innerfidelity) sample might not be representative of other IE 800s. Once that's squared away I do plan to take a crack at it.

 Edit: Seems I was late for the ball. What Tyll said. 

melvin's picture

It seems like the frequency response is the same as Etymotic ER4P w/c is very flat. I like IEMs that are flat /neutral in response however for commuting, I feel like a bit of an elevated lows could help tune out some noise.

Great review!

ljokerl's picture

In my experience many manufacturers recognize & acknowledge that a bump in the bass frequencies can be beneficial in a noisy (e.g. commuting) environment. Maybe less so for IEMs, but defintely for portable headphones. 

Seth195208's picture