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Parent Category: Products

Category: Headphone Measurements

Created: 01 March 2016

I measured the Blue Ellas using a G.R.A.S. Model 43AG ear/cheek simulator, a Clio 10 FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, a Musical Fidelity V-Can headphone amplifier, and an Audio-gd NFB-1AMP amplifier for the distortion measurements. This is a “flat” measurement; no diffuse-field or free-field compensation curve was employed.

The Ellas’ frequency response is unusual in two ways. Judging from the right-channel response, it’s flatter than usual, with a much narrower peak in the 3kHz area than I’m used to seeing. The other unusual thing is that the response of the left channel doesn’t match that of the right. I tried reseating the left earcup many times, and even repeated my measurements a week later, but couldn’t get a closer match than is seen here. It could be because the left channel’s acoustics are different from the right’s. I’ve seen this before in active headphones, and assume that it’s because of the space consumed by the battery in one earpiece. It’s worth noting that in Blue’s first headphones, the Mo-Fis, which share the Ellas’ basic design and are also internally powered, the channels were much better matched.

This chart shows the Ellas’ frequency response in passive, active, and + (bass boost) modes. The response in active mode is the same as in passive, but the level in passive mode is 8.1dB lower. The response in + mode shows a bass boost about two octaves wide, centered at 65Hz.

This chart shows the results of adding 70 ohms of output impedance to the V-Can’s 5 ohms, to simulate the effects of using a typical low-quality headphone amp. Only the results in passive mode are shown, because in active mode the impedance of the source component doesn’t affect the response. Using a higher-impedance source has only a barely measurable, probably inaudible effect on the Ellas’ response.

This chart shows the Ellas’ measured right-channel frequency response compared with that of Oppo Digital’s PM-3s -- like the Ellas, one of only a few closed-back planar-magnetic headphones available -- and NAD’s Viso HP50s, my comparison standard for midpriced closed-back headphones. Out of curiosity, I also included Blue’s original headphones, the Mo-Fis, which have dynamic drivers instead of the Ellas’ planar magnetics. The Ellas have more or less the flattest measured response of the bunch, though that doesn’t necessarily mean they’re the flattest-sounding.

The spectral-decay (waterfall) chart shows a resonance only at around 500Hz, though overall there’s less bass resonance than I usually see in these charts.

The total harmonic distortion (THD) of the Ellas was higher than I’m used to measuring. At 90dBA, the THD is low above 50Hz, and of course most music has little content below 50Hz. The THD gets very high below 60Hz at 100dBA, but this is an extremely loud level that few people would want -- or be advised -- to listen to for more than a few seconds. I repeated this measurement a week later with a fresh calibration and got essentially the same result. The measurements were roughly the same in passive and active modes, so this distortion is apparently coming from the driver.

In this chart, the external noise level is 75dB SPL; the numbers below that indicate the degree of attenuation of outside sounds. For comparison, I’ve included the isolation plots of the Oppo Digital PM-3s (a closed-back planar magnetic design), the NAD Viso HP50s (a closed-back dynamic design), and the noise-canceling Bose QC25s. The Ellas’ isolation is below average for a closed-back design, though they do attenuate the upper mids and treble by 14-19dB.

The Ellas’ impedance in active mode, while specified as 10 ohms, is actually beyond my Clio analyzer’s limit of 1500 ohms. (The Clio is designed to measure the impedance of speakers, not electronics.) In passive mode, it’s flat at 54 ohms, with almost perfectly flat phase response. Electrical phase varies more in active mode, but this shouldn’t affect the Ellas’ sound.

The sensitivity of the Ellas, measured between 300Hz and 3kHz with a 1mW signal, was 95.8dB in passive mode (calculated for the specified 50 ohms passive impedance), 95.3dB in active mode (calculated for the specced 10 ohms active impedance). Note that because these sensitivity measurements are calculated for different headphone impedances, they use different signal voltages -- 0.22V for 50 ohms, 0.1V for 10 ohms -- and thus are not comparable. In my frequency-response measurements, cited above, I found that switching to active mode boosts the Ellas’ output by 8.1dB with the same test-signal voltage. In either mode, though, the Blues’ sensitivity was a little lower than average; the Ellas should play loud enough in active mode, but passive mode might be a little too quiet to reach satisfying levels with some music in some environments.

. . . Brent Butterworth
brentb@soundstagenetwork.com

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Parent Category: Products

Category: Headphone Measurements

Created: 15 February 2016

I measured the Edition Xes using a G.R.A.S. Model 43AG ear/cheek simulator, a Clio 10 FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, and a Musical Fidelity V-Can headphone amplifier. I tried the headphone at several different positions on the ear/cheek simulator, to find the one with the most bass and the most typical average response. This is a “flat” measurement; no diffuse-field or free-field compensation curve was employed.

This chart shows the Edition Xes’ frequency response, which is flat up to 1.5kHz. The strong peak at 3kHz is found with most headphones, and is thought to make them sound more like conventional speakers in a room, but this peak is stronger than we usually see. The bass is a little rolled-off compared with some other open-back planar-magnetic headphones.

Adding 70 ohms output impedance to the V-Can’s 5-ohm output impedance to simulate the effects of using a typical low-quality headphone amp boosts the Edition Xes’ bass below 80Hz by about 1dB -- a subtle difference.

This chart compares the Edition Xes with three other open-back planar-magnetic models: HiFiMan HE1000, Audeze LCD-3, and Oppo Digital PM-1. Compared with the HE1000s, the Edition Xes have less bass but also less treble above 3kHz, so the two might have a similar perceived tonal balance. But there’s no denying that the Edition Xes’ 3kHz peak is stronger than average.

Like the HE1000s’, the Edition Xes’ waterfall plot doesn’t look clean at first glance, but all those resonances in the high frequencies are extremely narrow and well spread out. There’s almost no resonance in the bass, which is unusual for headphones, even open-back models. I speculate that the only resonance seen here that might be readily audible is the one centered at 1kHz.

The total harmonic distortion (THD) of the Edition Xes is insignificant even at levels far too loud to listen to safely.

In this chart, the external noise level is 75dB SPL; the numbers below that indicate the attenuation of outside sounds. Like all open-back headphones, including the HiFiMan HE560s and Audeze LCD-Xes shown here, the Edition Xes offer essentially no isolation from outside sounds. I included the isolation measurement of the Oppo PM-3s to illustrate the difference between open- and closed-back models in this regard.

The impedance magnitude of the Edition Xes is almost perfectly flat at 21 ohms; the impedance phase is about as flat as it gets.

The sensitivity of the Edition Xes, measured between 300Hz and 3kHz with a 1mW signal calculated for the rated 25 ohms impedance, is 96.5dB. That’s below average for headphones in general, and much less than the specified 103dB (HiFiMan doesn’t specify the conditions for that measurement), but it should be adequate to get a fairly comfortable listening volume from a smartphone.

. . . Brent Butterworth
brentb@soundstagenetwork.com

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Parent Category: Products

Category: Headphone Measurements

Created: 01 February 2016

I measured the Everest Elite 700s using a G.R.A.S. Model 43AG ear/cheek simulator, a Clio 10 FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, and a Musical Fidelity V-Can headphone amplifier. I moved the headphones around to several different locations on the ear/cheek simulator to find the one with the most bass and the most characteristic response. This is a “flat” measurement; no diffuse-field or free-field compensation curve was employed. However, I did run a TruNote auto-EQ sweep (see review for details) to optimize the response of the Everest 700s for the ear/cheek simulator. For all measurements, I used a cabled connection; adding a Bluetooth transmitter introduces latency and thus requires gating, which introduces anomalies into the measuring.

This chart shows the Everest Elite 700s’ frequency response with noise canceling (NC) on. The results are fairly typical, although with a somewhat stronger peak at 3kHz than I’m used to seeing. (This may be an anomaly caused by TruNote’s attempt to calibrate itself for the G.R.A.S. 43AG’s metal cheek plate, fake rubber ear, and unnaturally round simulated ear canal.) The match between the left and right channels is the best I could achieve. I can’t be sure if this is the result of minor differences in the fit of the two earpieces on the ear/cheek simulator, or if the internal acoustics of the two earpieces are different (a phenomenon I’ve seen before in NC headphones, caused by the varying amounts of space occupied by the internal electronics).

This chart shows the frequency response of the Everest Elite 700s with NC on and with the headphones powered completely off. Obviously, the tonal balance is very different in the two modes; the JBLs have very little bass in passive mode, so best not to let the battery run down.

Adding 70 ohms of output impedance to the V-Can’s 5 ohms to simulate the effects of using a typical low-quality headphone amp has no effect in NC mode. In passive mode, the balance will get subtly more trebly with higher-impedance sources.

This chart compares the Everest Elite 700s with three other noise-canceling headphones -- the Bose QC25s, the Definitive Technology Symphony 1s, and the PSB M4U 2s -- all with NC on. The main difference between the JBLs and the others is the larger peak at 3kHz. Most headphones have such a peak somewhere in that octave of audio, but how big the peak should be remains a matter of debate (and, as noted above, it’s possible the peak is the result of the TruNote auto EQ slightly miscalibrating itself for the nonhuman characteristics of the test gear). The Everest Elite 700s also have less deep bass than the others, but considering that music seldom has much content below 30Hz, you probably wouldn’t notice that.

The Everest Elite 700s’ waterfall plot (shown here with NC on) is exceptionally clean in the bass, with much less resonance than I see with most headphones. There are a few ultra-high-Q resonances -- at about 6, 8, 12, and 16kHz -- but considering that they’re so narrow, so low in level (-40dB), and so high in frequency, I’d be surprised if anyone can hear them.

The total harmonic distortion (THD) of the Everest Elite 700s, shown here with NC on, is insignificant at the loud level of 90dBA, but the extremely loud level of 100dBA (which I include more for testing purposes than for any sort of real-world evaluation) pushes the internal amp or the driver over the limit, resulting in considerable distortion below 2kHz. But, as I always say, if you listen long at this volume, you won’t be hearing much of anything after a while.

In this chart, the external noise level is 75dB SPL; the numbers below that indicate the attenuation of outside sounds. I recently did some acoustical measurements of the cabins of jet airliners in flight, and found that most of the noise is between 100 and 1200Hz. In this band, the Everest Elite 700s are roughly the equal of the PSB M4U 2s -- but, as usual, both are handily beat by the Bose QC25s.

As often occurs with active headphones, the impedance of the Everest Elite 700s was greater than 1000 ohms in NC mode and thus immeasurable on my Clio analyzer. In passive mode the impedance is largely flat, averaging about 24 ohms and presenting an essentially flat phase response.

The sensitivity of the Everest Elite 700s, measured between 300Hz and 3kHz with a 1mW signal calculated for 32 ohms impedance (my default when measuring active headphones), is 97.2dB in passive mode and 103.6dB in active mode (NC on). Thus, the JBL Everest Elite 700s, unlike many noise-canceling headphones, still produce a decent amount of volume when their internal battery runs down.

. . . Brent Butterworth
brentb@soundstagenetwork.com

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Parent Category: Products

Category: Headphone Measurements

Created: 15 January 2016

I measured the Reference X20i’s using a G.R.A.S. Model RA0045 ear simulator, a Clio 10 FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, and a Musical Fidelity V-Can headphone amplifier. I used one of the medium-sized eartips (not the Super-Slim tips) because it’s what best fit the simulator. (The simulator has a round canal, not an oval canal like a real human ear.) This is a “flat” measurement; no diffuse-field or free-field compensation curve was employed.

This chart shows the frequency response of the X20i’s -- a very typical, by-the-book response curve for earphones, suggesting that the X20i’s will have a fairly neutral sound.

Adding 70 ohms of output impedance to the V-Can’s 5 ohms, to simulate the effects of using a typical low-quality headphone amp, has a huge effect on the Klipsches’ sound. The greater the output impedance of your source device, the more the X20i’s will tilt toward a trebly sound. This characteristic is typical of headphones using balanced armatures, but this is one of the more extreme examples I’ve seen.

This chart confirms what I stated above: the X20i’s have a very standard response. Here they’re compared with the PSB M4U 4s, the NuForce Primo 8s, and the Shure SE846s: all high-end earphones having balanced armatures or a combination of balanced armatures and dynamic drivers. It’s important to note that all of these headphones have a fairly neutral sound, which is reflected in the relatively even amounts of bass and treble shown in the chart.

Resonance in the X20i’s is generally mild; you can see the usual bass resonances, and also, at 10kHz, an unusual resonance of very low amplitude (approximately -40dB) and very narrow bandwidth that is nonetheless poorly damped. It’s hard to imagine, given the frequency, amplitude, and bandwidth of the resonance, that anyone could hear this other than an expert listener using test tones.

The total harmonic distortion (THD) of the X20i’s is pretty low, at 90dBA (measured with pink noise) -- a very loud listening level. At 100dBA -- an extremely loud level I include not because it applies to real-life listening but because it’s a hurdle some headphones can clear and some can’t -- the X20i’s exhibit significant distortion: 5-10% between 2 and 4kHz. You can probably hear that, but if you listen for long at 100dBA you won’t be hearing much for long.

In this chart, the external noise level is 75dB SPL (red line); the numbers below that indicate the attenuation of outside sounds. The X20i’s’ isolation (orange trace) is typical, at least when measured by the simulator and compared with the RBH EP3s (green) and PSB M4U 4s (purple). If the Super-Slim eartips are as good as Klipsch says, they should improve the isolation in an actual human ear canal.

The X20i’s exhibit a huge impedance swing, going from a low of 24 ohms at 20Hz to a high of 300 ohms at 8.7kHz. This, along with the accompanying large shift in impedance phase, is why the sound changes so much with higher-impedance sources.

The sensitivity of the X20i’s, measured between 300Hz and 3kHz with a 1mW signal calculated for the rated 50 ohms impedance, is 111.9dB, which is extremely high -- you can get very loud levels from the X20i’s with any source device.

. . . Brent Butterworth
brentb@soundstagenetwork.com

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Parent Category: Products

Category: Headphone Measurements

Created: 15 December 2015

I measured the Definitive Technology Symphony 1s using a G.R.A.S. Model 43AG ear/cheek simulator, a Clio 10 FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, and a Musical Fidelity V-Can headphone amplifier. I moved the headphones around on the ear/cheek simulator to find the position that produced the most bass and the most characteristic response. As I usually do with on-ear ’phones, I used the Model 43AG’s clamping mechanism to ensure a good seal. This was a “flat” measurement; no diffuse-field or free-field compensation curve was employed. For all measurements, I used a cabled connection; adding a Bluetooth transmitter introduces latency and thus requires gating, which introduces anomalies into the measurements.

This chart shows the Symphony 1s’ frequency response with noise canceling (NC) on. It’s unusual in that the bass response keeps rising all the way down to 10Hz. Also, most of the measurements of closed-back headphones that I’ve taken show more energy between 100 and 500Hz. I’m not sure if this is good or bad, but these two attributes do suggest that the Symphony 1s’ bass might sound a little unusual. This chart represents the best channel matching I could achieve, but I rarely take points off on this because the positioning of the earpiece on the simulator has such a big effect on the measurement.

This chart shows the frequency response of the Symphony 1s in their three wired listening modes: passive (power off), active (power on, no NC), and NC. Obviously, the sound changes significantly from passive to active to NC modes, but this is common among headphones with these options, and with many, the differences are larger. Active mode seems to have more bass resonance (“hump”) than NC mode, and a little more treble response. That’s surprising, because the bass sounds substantially more prominent in NC mode. It’s likely that the extra treble in active/no-NC mode makes the sound thinner than in NC mode.

Adding 70 ohms of output impedance to the V-Can’s 5 ohms, to simulate the effects of using a typical low-quality headphone amplifier, had no measurable effect in the Symphony 1s’ NC or powered mode (which is why I don’t show it here), but in passive mode it boosted the bass by 2-3dB and the treble by about 1dB, effectively increasing the Symphony 1s’ midrange dip.

This chart compares the Symphony 1s with two other noise-canceling headphones -- Bose’s QC25s and PSB’s M4U 2s -- all with NC on. The Boses are widely considered the market leader in noise canceling, and the PSBs have won nearly universal praise for their sound quality. The big difference is that the DefTechs have a midrange dip of 5-10dB between 700Hz and 2.3kHz. Don’t be too quick to condemn them for this -- lots of well-regarded headphones show a similar midrange dip.

The Symphony 1’s waterfall plot, shown here with NC on, reveals a few minor resonances between 2.5 and 10kHz, but these are well damped, and die out in just a few milliseconds.

The Symphony 1s’ total harmonic distortion (THD), shown here with NC on, is insignificant.

In this chart, the external noise level is 75dB SPL; the numbers below that indicate the degree of attenuation of outside sounds. For reference, the drone of jet-engine noise in an airliner cabin is typically between 50 and 200Hz. For comparison, I’ve included in this chart the measurements of the PSB M4U 2 and Bose QC25 headphones. With NC on, the Symphony 1s’ isolation is about average for NC headphones.

As is usual with active headphones, the Symphony 1s’ impedance is high in powered/NC mode, though from this test I often see impedances of 1000 ohms or more. In passive mode, the DefTechs’ impedance runs between 30 and 60 ohms with a bit of phase shift, which is why the response changes with high-impedance sources in passive mode.

The sensitivity of the Symphony 1s, measured between 300Hz and 3kHz with a 1mW signal and calculated for 32 ohms impedance (my default when measuring powered headphones), is 94.7dB in passive mode, 105.2dB in active mode (NC on). Thus, when their battery runs down, the Symphony 1s will likely play reasonably but not very loud with a smartphone or tablet used as the source.

. . . Brent Butterworth
brentb@soundstagenetwork.com

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Parent Category: Products

Category: Headphone Measurements

Created: 01 December 2015

I measured the RBH Sound EP3s using a G.R.A.S. Model RA0045 ear simulator, a Clio 10 FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, and a Musical Fidelity V-Can headphone amplifier. I primarily used one of the smaller Comply foam eartips supplied with the EP3s because it fit the simulator well, and I figure it’s what most listeners will prefer. For comparison, I also include a measurement taken with one of the supplied silicone tips. This is a “flat” measurement; no diffuse-field or free-field compensation curve was employed.

This is the frequency response of the EP3s using the smaller of the supplied Comply foam eartips. There’s a little more bass and treble output (or a little less midrange output) than I’m used to seeing.

This chart shows the EP3s’ frequency response with the Comply foam tip (green trace) and the medium-size silicone tip (purple trace). The slight difference is perhaps enough to cause the EP3s to sound slightly brighter with the silicone tip. Because the shapes and sizes of ear canals vary, so may the actual results you get with these tips.

Adding 70 ohms output impedance to the V-Can’s 5 ohms to simulate the effects of using a typical low-quality headphone amp has zero audible effect on the sound of the EP3s.

You can see from this chart that the EP3s (blue trace) have stronger bass and treble output than RBH’s EP1s (red trace), and that both have much less midrange energy than the PSB M4U 4s (green trace). The Sennheiser IE 800s -- which I included because they’re well-regarded earphones that also have ceramic enclosures -- have much less lower-treble response, but a stronger 10kHz response than any of the other headphones measured here.

Resonance in the EP3s is mild and well damped, other than the bass resonances that have shown up in almost every set of earphones I’ve measured.

The EP3s’ total harmonic distortion (THD) is low. At the loud listening level of 90dBA, the distortion will almost certainly be inaudible. A narrow THD peak at 2.7kHz rises to about 3.5% at 100dBA, but it’s probably not troublesome, considering that: 100dBA is way louder than most people would ever listen; the peak is narrow; and the first three distortion products will be at the high frequencies of 5.4, 8.1, and 10.8kHz.

In this chart, the external noise level is 75dB SPL; the numbers below that indicate the degree of attenuation of outside sounds. The EP3s’ isolation is fantastic with the supplied eartips of Comply (shown) or silicone (not shown, but almost exactly the same result). They reduce ambient noise in the “jet-engine band” of 100-200Hz by 17-20dB -- better, even, than most noise-canceling headphones can achieve.

The EP3s’ impedance magnitude is essentially flat at 16 ohms, as is the phase.

The sensitivity of the EP3s, measured between 300Hz and 3kHz with a 1mW signal calculated for the rated 16 ohms impedance, is 105.2dB, which is above average; the EP3s should play quite loudly, regardless of the source device used.

. . . Brent Butterworth
brentb@soundstagenetwork.com

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Parent Category: Products

Category: Headphone Measurements

Created: 01 November 2015

I measured the Viso HP30s using a G.R.A.S. Model 43AG ear/cheek simulator, a Clio 10 FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, and a Musical Fidelity V-Can headphone amplifier. I used the clamping mechanism on the ear/cheek simulator to ensure a good seal (as I always do with on-ear models), and moved the headphone around to several different locations on the simulator plate to find the one with the most bass and the best average of midrange and treble responses. This is a “flat” measurement; no diffuse-field or free-field compensation curve was employed.

This chart shows the HP30s’ frequency response, which is fairly flat. There’s a mild dip in the midrange, which I believe has something to do with the RoomFeel voicing (and anyway isn’t uncommon in headphones), plus a broad, relatively mild peak centered at 3.5kHz. In most of the headphones I measure, this peak -- which is intended to make headphones sound more like speakers in a room -- is narrower, higher in magnitude, and a little lower in frequency.

Adding 70 ohms of output impedance to the V-Can’s 5 ohms to simulate the effects of using a typical low-quality headphone amp shows a broad boost below 80Hz that maxes out at +1.5dB. It might barely be audible, but certainly wouldn’t be objectionable.

This chart compares the HP30s (blue trace) with NAD’s Viso HP50 over-ear (red) and Beyerdyamic’s T 51 p (green) and Bowers & Wilkins’ P3 (orange) on-ear models. These curves are normalized to 500Hz, which is near where the HP30s’ response is weakest; while it looks as if the HP30s have a lot more bass and treble than the others, they’re actually fairly close to what I measured from the HP50s.

The HP30s’ waterfall plot shows less bass resonance than usual (not so surprising, considering there’s not much enclosure to resonate), and only a few extremely narrow and almost certainly inaudible resonances at a few higher frequencies.

The measured total harmonic distortion (THD) of the HP30s is a little on the high side in the bass, although I didn’t notice it in my listening tests. (I could, however, hear the distortion when I cranked up Mötley Crüe’s “Kickstart My Heart” to a level louder than I’d ordinarily listen.) The THD is about 2% at 100Hz, measured at the high listening level of 90dBA measured with pink noise. At the extremely high level of 100dBA, which I use only for measurement purposes, it hits 3% at 100Hz, rising to 11% at 20kHz.

In this chart, the external noise level is 75dB SPL; the numbers below that indicate the level of attenuation of outside sounds. The HP30s don’t offer much isolation, but few passive on-ear models do. There’s little or no attenuation below 600Hz, and attenuation of only 5 to 7dB from 600Hz to 2kHz. The HP30s wouldn’t be a good choice for air travel.

The HP30s’ impedance magnitude is fairly flat, running at or near the specified 32 ohms, except for a peak at 37 ohms right around 50Hz. The impedance phase is also mostly flat.

The sensitivity of the HP30s, measured between 300Hz and 3kHz with a 1mW signal calculated for the specified 32-ohm impedance, averages 109.2dB, which means they’ll play loud from any source device.

. . . Brent Butterworth
brentb@soundstagenetwork.com

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Parent Category: Products

Category: Headphone Measurements

Created: 01 October 2015

I measured the HiFiMan HE1000s using a G.R.A.S. Model 43AG ear/cheek simulator, a Clio 10 FW audio analyzer, a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface, and a Musical Fidelity V-Can headphone amplifier. I moved the headphones around to several different locations on the ear/cheek simulator to find the one that produced the most bass and the most characteristic response. This is a “flat” measurement; no diffuse-field or free-field compensation curve was employed.

This chart shows the HE1000s’ frequency response, which is flat up to 1.5kHz, and rises sharply above that from 2 to 9kHz.

Adding 70 ohms output impedance to the V-Can’s 5 ohms to simulate the effects of using a typical low-quality headphone amp has no audible effect on the HE1000s’ frequency response.

This chart compares the HE1000s (blue trace) with HiFiMan’s HE560s (red trace) and Audeze’s LCD-3s (green trace). The HE1000s have a similar response to the HE560s, with about 5dB more energy between 5 and 9kHz, and a little more bass to help balance out that treble peak. The LCD-3s have much less treble energy above 2.5kHz, and a flatter measured response, than either HiFiMan model. Note that, unlike with most speakers, a flat measured response in headphones does not necessarily equate with a flat perceived response.

The HE1000s’ waterfall plot may not look very clean at first glance, but if you look close you’ll see that all those little blue streaks are resonances of very narrow bandwidth about -40dB below the test signal. The only resonance shown here that might be audible is the combination of two adjacent -20dB resonances near 5kHz.

The total harmonic distortion (THD) of the HE1000s is well below audible levels, even at the extremely high level of 100dBA, measured with pink noise.

In this chart, the external noise level is 75dB SPL; the numbers below that indicate attenuation of outside sounds. As is almost always the case with open-back headphones, the HiFiMan HE1000s provide essentially no noise isolation; any sounds from outside them will come right through.

The impedance magnitude of the HE1000s is nearly dead flat at 37 ohms; the impedance phase, too, is nearly flat.

The sensitivity of the HE1000s, measured between 300Hz and 3kHz with a 1mW signal calculated for the specified impedance of 35 ohms, is 88.1dB. Although that’s relatively low, as I say in the review, it was enough for me to get a fairly comfortable volume level from my smartphone.

. . . Brent Butterworth
brentb@soundstagenetwork.com