I measured the Phiaton MS 100 BAs 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. Measurements were calibrated for drum reference point (DRP), roughly the point at the center of the eardrum (in this case, the center of the measurement mike). I used the Phiatons’ medium-size eartips because those best fit the RA0045. This is a “flat” measurement; no diffuse-field or free-field compensation curve was employed.
This chart shows the frequency response of the MS 100 BAs. It’s surprisingly flat -- most earphones have a larger dip in the midrange and a bigger bump in the bass -- which suggests that the Phiatons may sound smoother, but less vivid and less exciting, than many of their competitors.
As with most headphones using balanced-armature drivers, 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 a large effect on the MS 100 BAs’ tonal balance. If you connect it to a high-quality source device, it has a flat response; if you connect it to a high-impedance source device (such as the headphone amps built into most laptops), the treble will be boosted a couple dB and the bass reduced by about 5dB -- easily audible differences.
The MS 100 BAs’ departure from the norm is visible in this comparison with NAD’s HP20 dynamic earphones and Sony’s XBA-H1 hybrid dynamic/balanced-armature earphones. The midrange dip visible in the NADs’ and Sonys’ responses is usually thought to produce a subjectively flatter response and a more spacious sound. However, the science here is still developing.
The Phiaton MS 100 BAs show no significant resonances above 800Hz, which is excellent performance.
The MS 100 BAs’ total harmonic distortion (THD) is relatively high; at 100Hz, it’s 2% at 90dBA and 7.5% at 100dBA. Competitors such as the Marshall Mode EQs post numbers more in the range of 1-2%. However, note that 100dBA (level measured with pink noise) is an extremely high listening level; I include it here mainly because some headphones can handle it and some can’t. Also note that research has shown that headphone distortion is rarely audible except when it’s very high.
In this chart, the external noise is at an SPL of 75dB; the numbers below that indicate the Phiatons’ attenuation of outside sounds. Their isolation is very good for earphones, reducing noise by 20dB at 100Hz (the middle of the “airplane cabin-noise band”) and by up to 32dB in the treble. Note that your results may not be as good, depending on the size and shape of your ear canals and on the size of eartips you choose.
This is the biggest impedance swing I can remember measuring in a passive headphone model: from 24 ohms in the bass to about 460 ohms at 20kHz. This is why the Phiatons’ tonal response changes so much when they’re used with a high-impedance source device.
The Phiatons’ sensitivity, measured between 300Hz and 3kHz with a 1mW signal and calculated for the rated 24 ohms impedance, is 110.8dB, which is exceptionally high. This means that the MS 100 BAs will be able to deliver high playback levels from practically any source device.
. . . Brent Butterworth
brentb@soundstagenetwork.com
I measured the Marshall Mode EQs 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. Measurements were calibrated for drum reference point (DRP), roughly the point at the center of your eardrum (in this case, the center of the measurement microphone). I used the medium-sized eartips because those best fit the RA0045. This is a “flat” measurement; no diffuse-field or freefield compensation curve was employed.
This is the frequency response of the Mode EQs in EQ1 mode. (The comparison with EQ2 mode is shown below.) This measurement may look very uneven, but it’s actually a fairly common response for earphones. The bass boost and the midrange peak at 2.5kHz are intended to compensate for the fact that the earphones effectively bypass the acoustical effects of the earlobes and ear canals.
This chart shows the Mode EQs’ frequency response in EQ1 and EQ2 modes. The response is effectively the same, except that EQ2 mode reduces bass by about 3dB.
Adding 70 ohms to the V-Can’s output impedance of 5 ohms, to simulate the effects of using a typical low-quality headphone amp, has a modest effect on the Mode EQs in EQ1 mode (shown here), but a much larger effect in EQ2. In EQ1, the higher-impedance source shows a bass boost of about 0.5dB and, beginning above 2.5kHz, a treble rolloff of about 2dB. In EQ2, though, using a low-quality amp (like the ones built into most Windows laptops and some cheap smartphones) will soften the sound significantly, boosting bass by about 2dB and, starting at about 1.5kHz, reducing the treble by a like amount.
You can see from this chart that the Mode EQs (shown here in EQ1 mode) have a more extreme bass boost and a more extreme upper-midrange/lower-treble peak than the NAD HP20s or the Sony XBA-H1s, both of which produce comparatively neutral sounds.
The Mode EQs’ spectral decay plot shows some unusual and very narrow resonances at 6, 8, and 12kHz, and a little more bass resonance than is usual for dynamic earphones, but there’s nothing particularly troubling here.
The total harmonic distortion (THD) of the Mode EQs in EQ1 mode is insignificant, showing a slight rise around 800Hz but never rising even to 2% at the very high listening level of 100dBA.
In this chart, the sound-pressure level (SPL) of external noise is 75dB; the numbers below that indicate attenuation of outside sounds. The Mode EQs’ isolation is perhaps a little better than average for earphones, with a reduction of 10 to 30dB through most of the audioband. Note that, depending on the size and shape of your ear canals and on the eartips you choose, your results may not be as good.
Here’s why the response in EQ2 mode changes a lot depending on the output impedance of the source device. The impedance swing in EQ2 is huge for earphones with dynamic drivers, dropping from 49 ohms in the bass to 17 ohms in the treble. It’s much less extreme in EQ1 mode, which has a maximum impedance of 31 ohms. I assume that the extreme impedance shift in EQ2 mode is due to the filter used in the EQ switch.
The Mode EQs’ sensitivity, measured between 300Hz and 3kHz with a 1mW signal calculated for the rated 30 ohms impedance, is 108.1dB in EQ1 mode, 107.0dB in EQ2 mode -- sensitive enough to get loud levels from practically any source device.
. . . Brent Butterworth
brentb@soundstagenetwork.com
I measured the Oppo PM-2s using a G.R.A.S. 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. Measurements were calibrated for ear reference point (ERP): i.e., roughly the point where the axis of your ear canal intersects with your palm when you press a hand flat against your ear. This is a “flat” measurement; no diffuse-field or freefield compensation curve was used. I experimented with the fit of the earpieces by moving them around on the plate of the ear/cheek simulator, and settled on the positions that gave the best bass response and the most characteristic result overall.
The Oppo PM-2s’ response is similar to those of most of the planar-magnetic headphones I’ve measured, with one noteworthy difference. Most planar-magnetics are flat to about 1.5kHz, above which frequency their response begins to rise. The PM-2s’ response starts rising gradually at about 500Hz, which means that their midrange should sound +3 to +5dB fuller.
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, does not significantly affect the PM-2s’ response. Thus, its tonal balance will be the same from any source device. That’s especially good for these headphones, which are designed to be used with portable devices.
This comparison shows that while the PM-2s produce considerably less treble energy than the HiFiMan HE-560 or HE-400i headphones, compared to the PM-1s they have roughly +2dB more treble from 2 to 3kHz, and +3dB more from 6 to 8kHz. The PM-2s seem to strike the most even tonal balance of all four models.
The spectral-decay (waterfall) plot shows slight resonances around 2kHz. However, these are so low in level, at about -40dB, that there’s little chance you’ll hear them, especially considering that external sounds leaking in through the open backs of the earpieces will likely be much higher in magnitude.
Distortion at 90dBA from the PM-2s was almost nonexistent, except for a rise to 2% at 400Hz. At 100dBA -- an extremely loud listening level you probably couldn’t tolerate for long -- the distortion rises to 4% at 400Hz and 3% at 230Hz. (Both of these peaks correspond with peaks at the same frequencies in the impedance measurement.) I heard no distortion when I was testing the PM-2s.
For open-back headphones, the PM-2s deliver better isolation than average. There’s no isolation below 1.5kHz, but it’s -5 to -15dB from 1.5 to 10kHz. However, most closed-back models deliver isolation in the -10 to -30dB range.
The PM-2s’ impedance is almost flat, with a magnitude of 31 to 32 ohms and negligible phase shift. There are a couple of small impedance “bumps” that correspond to the peaks noted in the high-level distortion test.
The PM-2s’ average sensitivity from 300Hz to 3kHz at the rated 32 ohms measures 103.7dB. That’s +2.1dB more than Oppo’s PM-1s, and roughly in the average range of over-ear headphone sensitivity -- very impressive for planar-magnetic headphones.
. . . Brent Butterworth
brentb@soundstagenetwork.com
I measured the NuForce Primo 8s using a G.R.A.S. 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. Measurements were calibrated for drum reference point (DRP), the equivalent of the headphones’ response at the surface of the eardrum. This is a “flat” measurement; no diffuse-field or free-field compensation curve was used. I used the medium-sized silicone eartips supplied.
The Primo 8s’ measured frequency response is unusual, and doesn’t correlate well with my perception of its tonal balance. The response below 1kHz is exceptionally flat, much like what I’ve measured from planar-magnetic headphones such as the Audeze LCD-3s -- most other earphones have a bump in the bass response. There’s a relatively mild peak at 2kHz, and above that the response rolls off quickly. Just goes to show that you need to be careful not to judge a set of headphones too strongly by its measured frequency response.
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, has a large effect on the Primo 8s’ measured response. The peak at 2kHz disappears entirely, and the treble rolloff becomes more severe by about -7dB. These earphones really demand a source with a low output impedance, at the very least a higher-quality smartphone such as an iPhone or a Samsung Galaxy S; an even better idea would be a separate headphone amp.
Compared to the Audiofly AF140 (a design with one dynamic driver and two balanced armatures) and the Sony XBA-H1 (one dynamic driver and one balanced armature), the Primo 8s show a much flatter response up to about 5kHz, but much less treble response.
The decay of the Primo 8s might look a tad messy, but this is an excellent result. First, see how clean the response is from 500Hz to 1kHz. That’s rare: Few other earphones I’ve measured can stop on a dime at frequencies between 500Hz and 1kHz. There are some long resonances at 6, 8, and 14kHz, but they’re very narrow and very low in level; there’s little chance they’d be audible.
The Primo 8s’ total harmonic distortion (THD) at 90 and 100dBA is modest. There’s a little, but this is an average to above-average result. At the loud-but-not-crazy-loud level of 90dBA, the THD below 1.5kHz is about 1%. Even at the very high level of 100dBA, THD is never higher than 3%.
In this chart, the external noise level is 75dB SPL; the numbers below that indicate the level of attenuation of outside sounds. Probably because of the occlusion of the G.R.A.S. ear simulator by the Primo 8’s relatively large driver enclosure, the NuForces deliver outstanding isolation. They should substantially reduce jet-engine noise, considering that they attenuate outside sound by -28dB at 100Hz and -33dB at 1kHz, and by even more between 2 and 10kHz.
The impedance plots of balanced-armature headphones usually show pretty wild swings, and the Primo 8s are no exception. You can see here that they peak at 59 ohms at 550Hz, then fall to just 6 ohms at 20kHz. Phase response is also extreme: flat through much of the audioband, but dropping to -67 degrees at 1.35kHz. All the more reason to make sure you mate the Primo 8s with a high-quality source device.
The Primo 8s’ average sensitivity from 300Hz to 3kHz at the rated 38 ohms measured 116.6dB. That’s very high, and indicates that the Primo 8s will play loud as hell from even the cheapest, crummiest MP3 player.
. . . Brent Butterworth
brentb@soundstagenetwork.com
I measured the Level Ins 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. Measurements were calibrated for drum reference point (DRP), roughly the point at the center of the listener’s eardrum (or, in this case, the center of the measurement microphone). I used the Samsungs’ medium-size memory-foam eartip because that’s what fit the RA0045 best. This is a “flat” measurement; no diffuse-field or free-field compensation curve was employed.
The Level Ins’ response clearly shows the cause of the bright tonal balance I heard. The rise in the bass centered at 130Hz is normal, as is the peak centered at 3kHz (if perhaps a tad high), but the relative amount of energy between 5 and 9kHz is extremely high. My guess is that the balanced armature Samsung uses as a tweeter is set for a level about 5dB too high.
Adding 70 ohms output impedance to the V-Can’s 5 ohms, to simulate the effects of using a typical low-quality headphone amp, usually has a large effect on earphones with balanced armatures. With the Level Ins, the effect is not large in magnitude, but it kicks the treble of an already bright-sounding headphone up another 1.5dB.
The Level Ins’ response is quite similar to that of Sony’s XBA-H1s, which I love so much, except that the Samsungs’ output between 6 and 9kHz is 5 to 10dB higher than the Sonys’. The Audiofly AF140s show more of a “boom’n’sizzle” response than either the Samsung or Sony earphones.
The Level Ins have one of the cleanest spectral-decay plots I’ve seen in any type of headphone or earphone, with near-zero resonance. I redid this measurement three times and got the same result every time; other headphones measured in the same session gave me more typical results.
The Samsungs’ total harmonic distortion (THD) is fairly average at 90dBA: typically, around 1%. But at 100dBA -- a very loud listening level -- the distortion is pretty high, and consistently so through much of the audioband, running 3 to 5% below 2kHz, then rising to 9% in a narrow peak centered on 4kHz.
In this chart, the external noise level is 75dB SPL; the numbers below that indicate the attenuation of outside sounds. The Level Ins’ isolation is very good for universal-fit earphones, reducing noise at 1kHz by about 15dB, and reducing noise by 35dB or more between 2.2 and 11kHz at higher frequencies. Between 5 and 12kHz, the isolation is 5 to 10dB better with the memory-foam tip than with the silicone tip.
The Level Ins’ impedance is low overall, remaining below 10 ohms up to 1.5kHz, but is flatter than usual for earphones with balanced-armature drivers. The impedance phase response is also close to flat.
The sensitivity of the Level Ins, measured with a 1mW signal calculated for the specified 16 ohms impedance, is 98.2dB. That’s enough to get you a reasonable level from a portable audio player, but most of the earphones I measure deliver 6 to 10dB more output from the same signal.
. . . Brent Butterworth
brentb@soundstagenetwork.com
I measured the Brainwavz S5s 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. Measurements were calibrated for drum reference point (DRP), which is roughly the point at the center of the eardrum (in this case, the center of the measurement microphone). I used the largest silicone eartips because those best fit the RA0045. This is a “flat” measurement; no diffuse-field or free-field compensation curve was applied.
The S5s’ frequency response shows that they’re something a little different. See that big peak in the response centered at 6.8kHz? Move it down to about 3kHz, drop it by about 5dB, and you’d have a totally normal, “by the book” earphone response. But as you can see, the response is very smooth through most of the audioband, and the average amount of treble energy pretty well balances the average amount of bass energy.
Adding 70 ohms to the V-Can’s 5-ohm output impedance, to simulate the effects of using a typical low-quality headphone amp, has the completely insignificant effect of elevating the S5s’ bass response by 0.5dB at 10Hz.
It’s interesting to see how similar the response of the Brainwavz S5s is to that of the NAD Viso HP20s, the earphones that so closely resemble it. But there are differences: the NADs have a little more bass, a little less treble. The Sony XBA-H1s have a flatter overall response than either competitor, but considerably less treble energy above 5kHz.
The S5s produce an extremely clean spectral-decay plot, with no significant resonances except a couple of very well-damped ones at 9.5 and 13kHz, which correspond with the response peaks that show up in the frequency response.
The S5s’ total harmonic distortion (THD) is very, very low. At 90dBA, the distortion basically disappears into the noise floor at frequencies above 100Hz. At 100dBA, it rises to about 2.2% at 20Hz -- still exceptionally low, especially considering that 100dBA (measured with pink noise) is an extremely loud level.
In this chart, the external noise level is 75dB SPL; the numbers below that indicate the degree of attenuation of outside sounds. The S5s’ isolation is outstanding for universal-fit earphones, reducing noise at 1kHz by about 30dB, and reducing noise at about 3kHz by as much as 47dB. Note that your results may not be as good, depending on the size and shape of your ear canals and on the eartips you use.
The S5s’ impedance is fairly low, running almost dead flat at 17 ohms. The impedance phase response is essentially flat up to 10kHz.
The sensitivity, measured between 300Hz and 3kHz with a 1mW signal and calculated for the rated impedance of 16 ohms, is 105.1dB. That’s about average, and should be plenty enough to get you ample volume with any portable device.
. . . Brent Butterworth
brentb@soundstagenetwork.com
I measured the Oppo PM-1 headphones using a G.R.A.S. 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. Measurements were calibrated for ear reference point (ERP), which is roughly the point where the axis of your ear canal intersects with your palm when you press your hand flat against your ear. This is a “flat” measurement; no diffuse-field or free-field compensation curve was employed. I experimented with the fit of the earpieces by moving them around on the plate of the ear/cheek simulator, settling on the positions that gave the best bass response and the most characteristic result overall.
The PM-1s measure much like the other planar-magnetic headphones I’ve tested. It’s common for headphones to have a peak at 3kHz, which is thought to make headphones sound more like speakers in a real room -- but this peak is mild, at about +6dB (a lot of them are more like +12dB). Another mild, and very narrow, peak occurs at 8.8kHz.
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, has no real effect on the PM-1s. That might not be a big deal with most planar-magnetics -- few are designed to be driven by portable devices -- but it’s important with the PM-1s. It suggests you won’t hear a change in tonal balance when you switch from a good high-end amp to a portable source device.
In this comparison with two other planar-magnetic headphone models, Audeze’s LCD-X and HiFiMan’s HE-6, the PM-1s have the flattest-looking response, which suggests they will probably have a fairly flat sound and won’t be an outlier.
The spectral-decay (waterfall) plot shows no major or troublesome resonances.
The PM-1s’ total harmonic distortion (THD), at 90 and 100dBA, is generally very low, which is the norm for planar-magnetic headphones, although there is a little band of distortion between 200 and 300Hz. The important number here is the 90dBA result; that’s a usable (if quite loud) listening level, and there the distortion is just 2%, which is barely audible. At 100dBA, a level useful only for measurement comparisons, the distortion is 6%.
For what it’s worth, the PM-1s deliver better isolation than any other open-back planar-magnetic I’ve measured: -16 to -20dB above 4kHz. Still, though, as with all open-back ’phones, there’s no attenuation of sound below 1kHz.
The PM-1s’ impedance is effectively flat, with a magnitude of 32 ohms (same as the spec), and negligible phase shift.
The Oppos’ average sensitivity from 300Hz to 3kHz at the rated 32 ohms measures 101.6dB. That’s excellent for a planar-magnetic, although about -2 or -3dB below what typical over-ear headphones might deliver.
. . . Brent Butterworth
brentb@soundstagenetwork.com
I measured the KEF M200 earphones using a G.R.A.S. 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. Measurements were calibrated for drum reference point (DRP), the equivalent of a earphone’s response at the surface of your eardrum. This is a “flat” measurement; no diffuse-field or free-field compensation curve was employed. I used the medium-size silicone tips that I received with the review samples. Because of the large diameter of the M200s’ sound tubes, I had to press lightly with a fingertip to get a good seal in the ear simulator.
There’s some disagreement about what constitutes a good frequency-response measurement for earphones, but I think all experts would agree that this one looks unusual. That dip in the midrange centered at about 900Hz is fairly common, but here it’s about -6dB lower than I usually measure. The treble response above 4kHz is cleaner than I’m used to seeing, with just one strong, narrow peak at 8kHz instead of the usual multiple, spread-out peaks.
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 does affect the M200s’ performance, but only in a band of about one-third of an octave centered at 13kHz, where the response drops about -4dB with the high-impedance source. This would be audible to most people, although whether you’d perceive it as an improvement in or a degradation of the sound would depend on your hearing and taste.
This comparison of the M200s with NAD’s Viso HP20 and Bowers & Wilkins’ C5 earphones suggests that the KEFs are the least likely to be perceived as having a flat response, thanks to that big midrange dip. To my ears (and those of many other reviewers), the Viso HP20s sound fairly flat, the C5s a little on the bassy side.
The spectral-decay (waterfall) plot looks clean except for one very strong resonance at 4.8kHz. But given the narrowness of this resonance, I expect it would be audible only with certain pieces of music, and then only fleetingly.
The total harmonic distortion (THD) at 100dBA is a little high relative to the best earphones I’ve measured, hitting about 3% at 1kHz, but given that 3% isn’t such a high distortion level in transducers, and that 100dBA is an extremely loud playback level, I doubt you’d encounter this flaw in normal listening.
In this chart, the external noise level is 75dB SPL; numbers below that indicate the degree of attenuation of outside sounds. Thanks probably to its big, fat 6.8mm sound tubes, the M200s deliver good isolation from outside sounds. In the key band between 100Hz and 1kHz, the reduction ranges from -11dB at 100Hz to -27dB at 1kHz, and even better at higher frequencies.
The impedance magnitude is almost dead flat (if unusually low) at 12.5 ohms; the impedance phase is also almost entirely flat.
The M200s’ average sensitivity from 300Hz to 3kHz at the rated 12 ohms measures 96.7dB, which is -7 to -10dB lower than I measure with typical earphones. That’s because of the big midrange dip. With the M200s, you’ll probably need to turn your smartphone up to nearly maximum volume.
. . . Brent Butterworth
brentb@soundstagenetwork.com
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