Reviewed on: SoundStage! Solo, February 2019
I measured the Stellias using laboratory-grade equipment: a G.R.A.S. Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, and a Clio 10 FW audio analyzer. For isolation measurements, I used a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface. The headphones were amplified using a Musical Fidelity V-CAN or an Audio-gd NFB-1AMP. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed.
The above chart shows the Stellias’ frequency response. This is a little flatter than I typically measure from audiophile headphones. There’s a very mild resonant bass bump centered at 100Hz, and less of a pronounced peak between 2 and 4kHz than most audiophile headphones exhibit.
This chart shows how the Stellias’ tonal balance changes when they’re used with a high-impedance (75 ohms) source, such as an inexpensive laptop or some cheap professional headphone amp -- or more likely in the Stellias’ case, a tube amp with transformer output (although that still wouldn’t be near 75 ohms). Using the higher-impedance source produces an increase in bass of 2 to 2.5dB below 400Hz.
This chart shows the Stellias’ right-channel response compared with the Focal Clear, HiFiMan HE1000 V2, and Sennheiser HD 800 S headphones. You can see a bit of family resemblance between the Stellias and the Clears, although they have significant differences. The HE1000 V2 and the HD 800 S headphones have a lot more treble energy and less bass energy than the Stellias.
Across almost the entire audioband, the Stellias’ spectral decay (waterfall) chart shows a little more resonance than I’m used to seeing, but it’s almost entirely damped out within 6ms (one full cycle at 167Hz), so it’s very unlikely to be audible.
The Stellias’ measured total harmonic distortion (THD) is inconsequential at the loud listening level of 90dBA (measured with pink noise). At the extremely loud level of 100dBA, it gets up to around 4% below 100Hz, but in the bass, 4% isn’t a big deal. (The generally accepted figure for audible harmonic distortion in subwoofers is 10%.)
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. Isolation of the Stellias is in the same ballpark as other closed-back models such as the Audeze LCD2 Closed-Backs and the NAD Viso HP50s -- plenty enough to shield you against jibber-jabber and light background music in the unlikely event you bring your Stellias to Starbucks.
The impedance magnitude of the Stellias averages about 40 ohms, and runs as high as 56 and as low as 31 ohms. That swing in the bass is what produces the difference in response when switching from a low-impedance source to a high-impedance source. Despite the fairly large magnitude swing, the impedance phase is reasonably flat.
Sensitivity of the Stellias, measured between 300Hz and 3kHz, using a 1mW signal calculated for 35 ohms rated impedance, is 104.0dB. For a large set of audiophile headphones, that’s really impressive -- feel free to plug them straight into your smartphone if you like.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, February 2019
I measured the Ultimate Ones using a G.R.A.S. Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, 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 amp, with an Audio-gd NFB-1AMP used for distortion measurements. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed.
The above chart shows the Ultimate Ones’ frequency response. This looks typical except for the pronounced dip between 300Hz and 2kHz. Note the roughly three-octave-wide bump in the bass response. Because the bump is so wide, it will tend to make the bass sound moderately elevated in level rather than boomy.
This chart shows how the Ultimate Ones’ tonal balance changes when they’re used with a high-impedance (75 ohms) source, such as a cheap laptop or some cheap professional headphone amps. There’s barely any difference, just a roughly 1dB bass boost between 30 and 60Hz with the high-impedance source.
This chart shows the Ultimate Ones’ right-channel response compared with a few other headphones in the same price range (AudioQuest NightHawk, HiFiMan HE400i, and Sennheiser Massdrop HD 6XX). Note that these are all referenced to 94dB at 500Hz. Obviously, the Ultimate Ones’ deep midrange dip will make them sound quite a bit different than the other models shown here.
The spectral decay (waterfall) chart shows a little more resonance in the bass than I’m used to seeing, but it’s at -20dB right from the start and falls below -40dB after 8ms, or about one-and-a-half cycles at 200Hz, so I would be very surprised if it’s audible.
At the loud listening level of 90dBA (measured with pink noise), the Ultimate Ones’ measured total harmonic distortion (THD) is a little high below 100Hz. The bass distortion doesn’t rise much at the extremely loud level of 100dB, but there’s a little more distortion between 1.3 and 2.2kHz.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. I’d classify the Ultimate Ones as semi-open-back, as they offer more isolation than fully open headphones such as the HiFiMan HE400i’s, but less isolation than a typical closed-back model such as the NAD Viso HP50.
The impedance magnitude of the Ultimate Ones averages about 37 ohms and doesn’t vary much from that, and the impedance phase is also flat.
Sensitivity of the Ultimate Ones, measured between 300Hz and 3kHz, using a 1mW signal calculated for 35 ohms rated impedance, is 97.0dB. So they’ll probably play loud enough from most smartphones, although you might not be able to get them really cranking.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, January 2019
I measured the HE6se headphones using a G.R.A.S. Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, 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 amp, with an Audio-gd NFB-1AMP used for distortion measurements. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed.
The above chart shows the HE6ses’ frequency response. This is comparable to what I’ve seen with many HiFiMan models, and not far outside what I’ve seen from most open-back planar magnetics, except that the peak between 3 and 4kHz (which is generally considered necessary to create the illusion of hearing real speakers in a real room) is a few dB higher than normal.
This chart shows how the HE6ses’ tonal balance changes when they’re used with a high-impedance source, such as a cheap laptop or some cheap professional headphone amps. (Of course, the headphones’ low sensitivity means it’s practically impossible to use them with a low-quality amp.) There’s essentially no difference at all, which means the HE6ses’ tonal balance probably won’t change if you decide to use them with, say, a high-output-impedance tube amp.
This chart shows the HE6ses’ right-channel response compared with three other open-back planar-magnetic models (the Audeze LCD-Xes, Focal Clears, and Quad ERA-1s with the leather pads). The strength of that peak between 3 and 4kHz is evident here; no way these headphones won’t sound a little bright.
The midrange hash -- the very narrow, high-Q resonances between 3 and 5kHz -- of the HE6ses are seen in almost all the spectral decay (waterfall) measurements I’ve done of planar-magnetic headphones, but here they’re focused across a smaller band and are higher in magnitude. This corresponds with the big peak in the frequency response in this same range. Meanwhile, the bass resonance is practically non-existent, the least I can remember measuring in any headphones.
The HE6ses’ measured total harmonic distortion (THD) is pretty low, except for a weird little bump to about 3.5% centered near 1.5kHz. This is at the extremely loud listening level of 100dBA, though.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. The HE6se headphones offer among the least isolation from outside sounds that I’ve ever measured -- but of course, open-back models aren’t supposed to isolate you from outside sounds, and the fact that the HE6ses provide so little isolation also means that the acoustical impedance of their rear grilles is very low, which may have contributed to the big sense of space I heard from these.
As usual with planar-magnetic headphones, the impedance magnitude of the HE6ses is almost perfectly flat. It’s about 65 ohms through the entire audio range, and the impedance phase is also flat.
Brace yourself, because the sensitivity of the HE6ses, measured between 300Hz and 3kHz, using a 1mW signal calculated for 50 ohms rated impedance, is 79.2dB, more than 4dB lower than the already-low rating of 83.5dB. Which means you will definitely need an exceptionally powerful amp for these.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, February 2019
I measured the ERA-1s using a G.R.A.S. Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, 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 amp, with an Audio-gd NFB-1AMP used for distortion measurements. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed.
The above chart shows the ERA-1s’ frequency response with the perfed leather pads. What’s unusual here is the small peak centered at 1kHz, and the fact that the peak at 3kHz is lower in magnitude than usual; typically, the peaks in a headphone’s response between 5 and 10kHz are a few dB lower than the 3kHz peak.
This chart shows the acoustical effects of the perfed leather and velour pads. The velour pads should deliver a softer treble and a fuller tonal balance, at the likely expense of perceived treble detail and spaciousness.
This chart shows how the ERA-1s’ tonal balance changes when they’re used with a high-impedance source, such as a cheap laptop or some cheap professional headphone amps. With the high-impedance source, there’s just a barely measurable (and not audible) reduction in bass of a fraction of a decibel from 20 to 30Hz.
This chart shows the ERA-1s’ right-channel response compared with two other open-back planar-magnetic models (the HiFiMan Anandas and the Audeze LCD-Xes), as well as the AKG N700NCs, a closed-back model said to deliver response very close to the “Harman curve,” shown in research by Harman International to be the preferred over-ear headphone response for most listeners. The ERA-1s are generally similar to the other planar magnetics.
The midrange hash (very narrow, high-Q resonances) shown in the ERA-1s’ spectral decay (waterfall) chart is typical of planar-magnetic headphones, although the ERA-1s’ hash covers a wider band than most.
The ERA-1s’ measured total harmonic distortion (THD) is generally low, although actually slightly higher than I typically measure from planar-magnetic headphones. It reaches an audible level only in the bottom octave of bass (20-40Hz), and at an extremely loud level, but most music has little or no content in that range, and most of the distortion harmonics are so low in pitch that they’ll be hard to hear.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. Like almost all open-back models, the ERA-1s offer little isolation from outside sounds -- much less than that of the Audeze LCD2 Closed-Backs also shown here.
As usual with planar-magnetic headphones, the ERA-1s have an almost perfectly flat impedance curve, running about 21 ohms through the entire audio range, and impedance phase is similarly flat.
Sensitivity of the ERA-1s, measured between 300Hz and 3kHz, using a 1mW signal calculated for 20 ohms rated impedance, is 93.4dB with the perfed leather pads and 96.1dB with the velour pads. This means that while you will likely get usable volume if you plug the ERA-1s straight into a smartphone, you’ll get the best performance from the ERA-1s if you use a high-quality portable music player or amplifier.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, December 2018
I measured the LCD2 Closed-Backs using a G.R.A.S. Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, 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 amp, with an Audio-gd NFB-1AMP used for distortion measurements. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed.
The above chart shows the LCD2 Closed-Backs’ frequency response. This is a typical measurement for audiophile-oriented headphones, with maybe just a dB or two more bass than many large planar-magnetic models offer.
This chart shows how the LCD2 Closed-Backs’ tonal balance changes when they’re used with a high-impedance source, such as a cheap laptop or some cheap professional headphone amps. This is a little surprising, because most planar-magnetic headphones show no variance on this test. With the LCD2 Closed-Backs, the higher-impedance source produces a boost of 1 to 1.5dB between 1.5 and 3kHz.
This chart shows the LCD2 Closed-Backs’ right-channel response compared with two other audiophile-oriented headphones (the Fostex TH909s and Focal Elegias), as well as the AKG N700NCs, a new closed-back model said to deliver response very close to the “Harman curve,” shown in research by Harman International to be the preferred over-ear headphone response for most listeners. The LCD2 Closed-Backs are clearly in the ballpark of a “standard” headphone response, with perhaps a little more treble and a slightly fuller midrange than we see in most over-ear headphones.
The LCD2 Closed-Backs’ spectral decay (waterfall) chart shows slight comb filtering effects between 2 and 6kHz that are commonly seen in planar-magnetic headphones, but they’re far better-damped than usual, probably because of the closed back and perhaps some damping material inside.
Measured total harmonic distortion (THD) of the LCD2 Closed-Backs is near zero, barely above the noise floor of the measurement.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. The LCD2 Closed-Backs’ isolation is about average for headphones of this type, and notably better than a conventional, smaller set of closed-back headphones such as the NAD Viso HP50s (also shown) -- and, of course, better than Audeze’s open-back models.
Here’s an unusual result -- most planar-magnetic models have a dead-flat impedance curve, but the LCD2 Closed-Backs’ impedance response has a large peak of 108 ohms, centered at 2.4kHz; through most of its range, the impedance magnitude is flat at 72 ohms. Despite the fairly large magnitude swing, the phase response shows just a mild shift at the same frequency. This peak is why the response of the headphones changes when they’re used with a high-impedance source.
Sensitivity of the LCD2 Closed-Backs, measured between 300Hz and 3kHz, using a 1mW signal calculated for 70 ohms rated impedance, is 97.5dB (the rating is 97dB). That’s high enough that you’ll get a somewhat usable volume from typical smartphones, but low enough that you’ll want to use a high-quality portable music player or amplifier for most of your listening.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, January 2019
I measured the T60RPs using a G.R.A.S. Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, 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 amp, with an Audio-gd NFB-1AMP used for distortion measurements. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed.
The above chart shows the T60RPs’ frequency response. This is a fairly typical measurement, except that the T60RPs show a response peak at 1.3kHz and a dip between 2 and 4kHz, while most good-sounding headphones show a dip around 1.3kHz and a peak around 3kHz.
This chart shows how the T60RPs’ tonal balance changes when they’re used with a high-impedance source, such as a cheap laptop or some cheap professional headphone amps. With the high-impedance source, there’s a roughly 1.5dB boost in the bass below 70Hz, which will be just barely noticeable.
This chart shows the T60RPs’ right-channel response compared with two moderately priced open-back models (the HiFiMan HE400i’s and the Massdrop-Sennheiser HD6XXes), as well as the AKG N700NCs, a new closed-back model said to deliver response very close to the “Harman curve,” shown in research by Harman International to be the preferred over-ear headphone response for most listeners. Besides the peak at 1.3kHz instead of 3kHz, the T60RPs have a little more bass than the open-back models, and less than the AKGs.
The T60RPs’ spectral decay (waterfall) chart shows a little bit of resonance in the bass, but overall it’s pretty clean, and doesn’t have the hash we often see with planar-magnetic headphones between 2 and 5kHz.
Measured total harmonic distortion (THD) of the T60RPs is pretty high in the bass (note that I’ve expanded my scale from the usual 20% max to 50% max in order to show the result at 100dBA). I repeated this measurement with a different amp on a different day just to check it, but the result was comparable.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. You can see that the semi-open-back T60RPs’ isolation is better than that of the open-back HiFiMan HE400i and Monoprice M650 headphones, but not as good as closed-back headphones such as the NAD Viso HP50s can provide.
As expected from planar-magnetic headphones, the T60RPs are just about dead-flat in impedance magnitude at 49 ohms, with only a slight bump in the curve at 65Hz. The impedance phase is essentially flat, too.
Sensitivity of the T60RPs, measured between 300Hz and 3kHz, using a 1mW signal calculated for 50 ohms rated impedance, is 90.8dB, slightly lower than the rated 92dB. This is low enough that you’ll want to use a high-quality portable music player or amplifier; you could probably use the T60RPs with a smartphone or computer in a pinch, but they won’t sound very loud.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, December 2018
I measured the R-220s using a G.R.A.S. Model 43AG ear/cheek simulator/RA0402 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 amp. On the Model 43AG, I used the new KB5000 and KB5001 anthropomorphic simulated pinnae for most measurements, and the stainless-steel coupler included with the RA0045 for certain other measurements as noted. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed.
The above chart shows the R-220s’ frequency response measured with the KB5000 and KB5001 anthropomorphic simulated pinnae. Above 1kHz, this measurement looks typical for earphones. But below 1kHz, there’s a lot less bass than we usually see.
This chart shows the R-220s’ right-channel frequency response measured with the RA0045 ear simulator’s stainless-steel coupler (which I’ve used for years) and the new KB5000 simulated pinna, which I recently switched to because it more accurately reflects the structure and pliability of the human ear and provides a more realistic simulacrum of what you’ll actually experience with headphones or earphones. This is just for sake of comparison with older measurements of mine.
As usual with earphones incorporating balanced-armature drivers, the R-220s show a tonal balance shift when you go from a low-impedance source device (typically between 0.5 and 5 ohms) to a relatively high-impedance source device (typically 75 to 125 ohms). In this case, the bass and lower midrange will be attenuated by about 1dB, and the treble boosted by 2 to 3dB.
This chart shows the R-220s’ right-channel response compared with two other earphones in the same price range (the Campfire Comets and the Acoustic Research AR-E010s used in wired mode), as well as the AKG N5005s, the earphones that currently best conform to the “Harman curve,” shown in research by Harman International to be the preferred in-ear headphone response for most listeners. Again, the R-220s’ response is much more heavily balanced toward the treble than the other models -- even the AR-E010s, which have only a little more bass but also balance out the sound with a somewhat reduced treble response.
The R-220s’ spectral decay (waterfall) chart shows only an extremely high-Q (i.e., narrow) and weak (-40dB) resonance around 5kHz. There’s no chance this would be audible.
The R-220s’ distortion is modest for balanced-armature earphones, running about 1% at the loud listening level of 90dBA, and 2% at the extremely loud level of 100dBA.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. The R-220s’ isolation (shown with and without its flange) is about average for earphones of this type, maybe a little above average between 500Hz and 1kHz.
Most balanced-armature earphones show some impedance swing, but the R-220s show a little more than most, rising from the rated 29 ohms below 500Hz to a high of about 130 ohms at 20kHz. The phase also swings a lot, from 0 degrees in the bass to +60 degrees at 20kHz. This is why the sound changes with high-impedance sources.
Sensitivity of the R-220s, measured between 300Hz and 3kHz, using a 1mW signal calculated for the rated 29 ohms impedance, is 97.2dB. That’s low for earphones; the reason for the low number is that the response is skewed toward the treble. So the upper mids and treble will be a lot louder than that, but the bass will be lower.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, December 2018
I measured the Solarises using a G.R.A.S. Model 43AG ear/cheek simulator/RA0402 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 amp. On the Model 43AG, I used the new KB5000 and KB5001 anthropomorphic simulated pinnae for most measurements, and the stainless-steel coupler included with the RA0045 for certain other measurements as noted. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed.
The above chart shows the Solarises’ frequency response measured with the KB5000 and KB5001 anthropomorphic simulated pinnae. This is pretty standard response for earphones, except that they have less bass and treble response (or more midrange response) than we usually see. The measurement here was done with medium-size Campfire Marshmallow foam tips. I also tried using the supplied medium-size silicone tips, and the result was almost identical.
This chart shows the Solarises’ right-channel frequency response measured with the RA0045 ear simulator’s stainless-steel coupler (which I’ve used for years) and the new KB5000 simulated pinna, which I recently switched to because it more accurately reflects the structure and pliability of the human ear and provides a more realistic simulacrum of what you’ll actually experience with headphones or earphones. This is just for sake of comparison with older measurements of mine.
Here you can see how the Solarises’ tonal balance changes when they’re used with a high-impedance source, such as a cheap laptop or some cheap professional headphone amps. As usual with earphones incorporating balanced armature drivers, there’s a tonal balance shift when you go from a low-impedance source device (typically between 0.5 and 5 ohms) to a relatively high-impedance source device (typically 75 to 125 ohms). In this case, the bass and lower midrange will be attenuated by 2 to 4dB relative to the treble. Note that this measurement is normalized to 1kHz; it would probably be more accurate to say the treble output from the balanced armatures is boosted by 2 to 4dB and the bass from the dynamic driver stays about the same.
This chart shows the Solarises’ right-channel response compared with a few other midpriced earphones: the Fidue A85 Virgos, Campfire’s own Comet earphones (which cost less than one-seventh as much, but I was curious to see if there was a family resemblance), and the AKG N5005s, the earphones that currently best conform to the “Harman curve,” shown in research by Harman International to be the preferred in-ear headphone response for most listeners. The Solarises’ response does look similar to the other brands, just flatter.
The Solarises’ spectral decay (waterfall) chart shows no significant resonance at any frequency within the range of this measurement (i.e., above 200Hz).
The Solarises show a little more distortion than I’m used to seeing in high-end earphones, and the distortion seems to be coming mostly from the midrange driver; it’s about 1 to 2% at the fairly loud level of 90dBA, and a little above that at 100dBA. That may seem like a lot of distortion if you’re used to looking at amplifier distortion numbers, but in speakers, headphones, and earphones, this level is barely, if at all, audible.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. The Solarises’ isolation is maybe a hair better than average for large earphones, although a small earphone such as the Campfire Comet (also shown here) may achieve somewhat better isolation because it can go a little deeper into the ear.
The Solarises’ impedance response is very low in the bass, at about 3 ohms. Once the balanced armatures kick in, it rises to 7 to 11 ohms, and the phase shifts positive. This is why the tonal balance changes with high-impedance source devices.
Sensitivity of the Solarises, measured between 300Hz and 3kHz using a 1mW signal calculated for 10 ohms impedance is 115.7dB, which is very high for high-end earphones.
. . . Brent Butterworth
brentb@soundstagenetwork.com
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