Reviewed on: SoundStage! Solo, April 2021
I measured the KEF Mu3 earphones using laboratory-grade equipment: a GRAS Model 43AG ear/cheek simulator with the RA0402 high-resolution ear simulator with KB5000/KB5001 simulated pinnae, and a Audiomatica Clio 12 audio analyzer. For isolation measurements, I used a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface. An Mpow BH259A Bluetooth transmitter was used to send signals from the Clio 12 to the earphones. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed. Note that my usual impedance and sensitivity measurements are irrelevant for wireless headphones, and impossible to do without disassembling them, and are thus not included here. If you’d like to learn more about what our measurements mean, click here.
The above chart shows the Mu3s’ frequency response measured with the RA0402 ear simulator. The most interesting thing to see here is in the lower-midrange and bass response, which starts to rise below about 200Hz, rather than below 500Hz as in most earphones. This response corrects for the lower-midrange boominess and bloat generally noted in earphones and headphones, and which the Harman curve corrects.
This chart shows the Mu3s’ right-channel response compared with other true wireless earphones (Technics EAH-AZ70Ws and Status Audio Between Pros), as well as with the AKG N5005s, the passive earphones said to best reflect the Harman curve. The Mu3s track the Harman curve more closely than any other earphones I’ve measured, other than the N5005s, although the KEFs have a little less energy at 2kHz and more between 5 and 7kHz.
The Mu3s’ spectral-decay (waterfall) response shows no significant resonances.
The Mu3s’ distortion is very low at the loud level of 90dBA (measured with pink noise), and barely any higher at the extremely loud level of 100dBA.
This chart shows the Mu3s’ isolation in its various modes (ANC on, ANC off, Ambient) versus two other true wireless models with ANC—the Technics EAH-AZ70W and the 1More EHD9001TA earphones, both of which have excellent noise canceling. The results with the KEFs’ ANC are strange, but correspond with what I heard. Rather than focusing on noise in the band between about 100 and 500Hz—where most airplane cabin noise resides and where ANC tends to be most effective—the Mu3s’ noise canceling is most effective above 300Hz. It doesn’t appear to me that much engineering effort was put into the Mu3s’ noise canceling.
Latency with the Mu3s connected to the Mpow BH259A Bluetooth transmitter is 243ms. In this case, the SBC codec is used because the BH259A doesn’t have AAC, but AAC works much the same way as SBC and should have similar latency. The latency seen here is enough to create lip-sync problems when watching YouTube videos or playing video games, but that will also depend on the latency of the display you’re using.
Bottom line: The Mu3 earphones have generally excellent measured performance, with low distortion and resonance, and a frequency response clearly shown to correlate well with listener preferences. However, if you are a frequent traveler (or expect to return to frequent travel) and want noise-canceling earphones to fly with, I’d recommend you look elsewhere.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, March 2021
I measured the 64 Audio Nio earphones using laboratory-grade equipment: a GRAS Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, and a Clio 12 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. Except as noted, I made all measurements with the M15 APEX modules installed. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed. If you’d like to learn more about what our measurements mean, click here.
This chart shows the Nios’ frequency response, with the factory-installed M15 APEX modules. This is close to a textbook response, but the bass bump is about 2dB lower and the peaks at 2.4 and 5kHz about 2dB higher.
Here we can see the way the APEX modules affect the Nios’ frequency response. The M20 module bumps the bass up about 2dB, while the MX module reduces it by 5dB at 100Hz and 10dB at 20Hz.
This chart shows how the Nios’ 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, or some exotic tube amps. The LID (Linear Impedance Design) is supposed to eliminate this concern. While the change here is less than I often see with balanced-armature earphones, there’s still a difference: with high-impedance sources, about a 1dB boost in the bass and a 1dB reduction in treble output.
This chart shows the Nios’ right-channel response with the M15 APEX module, compared with three other high-end earphones: the Meze Rai Pentas, the Technics EAH-TZ700s, and the AKG N5005s, which are said to be very close to the Harman curve target. You can easily see that the Nios’ upper-mid/lower-treble peaks are lower in magnitude than similar peaks in the other earphones.
The Nios’ spectral decay shows much stronger resonance in the bass than I normally see in earphones, perhaps due to its internal acoustics, which are said to include resonant chambers for the different drivers.
The Nios show a little bit of distortion at high listening levels, but at most it’s about 3%, which isn’t a lot for transducers. If you have them cranked really loud, you might encounter that distortion peak at 2.6kHz (with readily audible harmonics at 5.2, 7.8 and 10.4kHz), depending on what you’re listening to.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. The lower the lines, the better the isolation. I compared the Nios with the three different APEX modules installed (using the medium silicone tips, which fit the ear/cheek simulator best), versus two other high-end earphones: the Technics EAH-TZ700s and Audeze Euclids. There doesn’t seem to be much difference in the isolation with the different APEX modules.
True to the claims for LID, the Nios show one of the flattest (maybe the flattest) impedance-magnitude curves I’ve seen in balanced-armature earphones, averaging about 5 ohms with only a mild wrinkle in the treble (which is reflected in the phase measurement), and the likely cause of the changes in treble response with high-impedance sources.
Sensitivity of the Nios, measured between 300Hz and 3kHz, using a 1mW signal calculated for 6 ohms rated impedance, is just 95.1dB, much lower than the rated 105dB. However, this doesn’t square with my experience; based on what I’ve heard with other earphones using my Samsung S10 phone as a source, I think the Nios’ sensitivity would be somewhere around its rating. I derive the drive voltage for this test according to IEC 60268-7, which mandates a voltage that produces 1mW into the rated impedance, which in this case is just 77mV, versus 179mV for 32-ohm earphones. This method has worked fine for me in the past, and obviously has gotten the job done for countless others for more than three decades, but it doesn’t seem to work with a super-low-impedance model like the Nios.
Bottom line: My measurements suggest the Nios will sound a little on the soft side from a tonal balance standpoint. Otherwise, the design looks pretty solid, and the Nios are mostly free of the source-matching concerns that balanced-armature earphones usually present, although the measurements do nothing to convince me of the efficacy of (or need for) the APEX modules.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, March 2021
I measured the Emotiva Airmotiv GR1 headphones using laboratory-grade equipment: a GRAS Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, and a Clio 12 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. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed. If you’d like to learn more about what our measurements mean, click here.
This chart shows the Airmotiv GR1s’ frequency response. Nothing really out of the ordinary here—one could criticize the GR1s for being a little light in the treble and the bass, and a little bumped-up between 300 and 900Hz, but as we’ll see in the comparison chart, they’re roughly in line with industry norms.
This chart shows how the Airmotiv GR1s’ 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, or some exotic tube amps. There’s a little bit more bass with high-impedance sources.
This chart shows the Airmotiv GR1s’ right-channel response compared with two somewhat similar models (HiFiMan Sundara and Philips Fidelio X3 headphones), and the AKG K371 headphones, which are said to be very close to the Harman curve target. The measurements of the GR1s and the Fidelio X3s are quite similar (as expected from my listening tests), the Sundaras are more trebly, and the K371s have more bass and more treble—which the Harman research shows results in a subjectively flat response.
The GR1s’ spectral decay shows fairly strong resonances at about 500Hz, 4kHz, and 6kHz, which correspond with frequency-response dips and peaks in those regions; they’re high-Q resonances; I expect they’re not overtly audible but that they do affect the sound a bit.
As expected from my listening tests, the Airmotiv GR1s do show some distortion at high listening levels, getting into the range of 5% to 10% below 100Hz at the extremely high level of 100dBA, measured with pink noise. So if you like to listen loud, these aren’t the headphones for you—but unless you relish the idea of crippling tinnitus and not being able to understand normal conversation by the time you’re 60, you should just get used to lower volumes instead.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. The lower the lines, the better the isolation. I compared the GR1s with the similar Philips Fidelio X3, the closed-back AKG K371, and the fully open-back HiFiMan HE400i headphones. This is about the level of isolation I’d expect for semi-open headphones.
The Airmotiv GR1s’ impedance magnitude curve is typical for a dynamic-driver design, hovering in the mid-30-ohms range except for a peak at the driver’s resonant frequency of 58 ohms. In the electrical phase plot, there’s a little bit of a wrinkle in the bass, which is why the bass response increases a bit with high-impedance sources.
Sensitivity of the Airmotiv GR1s, measured between 300Hz and 3kHz, using a 1mW signal calculated for 32 ohms rated impedance, is 103.5dB. That’s high enough that the Airmotiv GR1s should play loudly from pretty much any source.
Bottom line: Other than high distortion at very loud listening levels, the Airmotiv GR1s are a very normal set of headphones that are free of troublesome quirks.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, March 2021
I measured the Sennheiser IE 300 earphones using laboratory-grade equipment: a GRAS Model 43AG ear/cheek simulator/RA0402 ear simulator with KB5000/KB5001 simulated pinnae, and a Clio 12 audio analyzer. For isolation measurements, I used a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface. The earphones were amplified using a Musical Fidelity V-CAN. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed. If you’d like to learn more about what our measurements mean, click here.
This chart shows the IE 300s’ frequency response. The bass looks pretty normal, and the response above about 5kHz looks pretty normal, but there’s something missing: a peak somewhere in the 2 to 4kHz range. The lack of this peak, and the rather prominent peak around 7.5kHz, are probably the reasons I sometimes found the upper harmonics of voices to be overemphasized.
This chart shows how the IE 300s’ 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, or some exotic tube amps. There’s no significant difference.
This chart shows the IE 300s’ right-channel response compared with the JVC HW-FW01, Shure Aonic 5, and the AKG N5005 earphones, the latter being the earphones that come closest to the Harman curve target. You can see that all the other models have a prominent peak somewhere between 2 and 4kHz.
This is a very clean spectral-decay plot, with no hint of an audible resonance.
The IE 300s have a little bit of distortion, but even if you really cranked them, you probably wouldn’t hear it: it maxes out a little above 2% THD at around 1kHz, at the extremely high level of 100dBA, measured with pink noise.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. The lower the lines, the better the isolation. The isolation of the IE 300s is not as good as I’d expect, given their over-the-ear cable routing; I’d guess that their compact, lightweight design makes them less isolating than the Shure Aonic 5s (also shown).
The IE 300s’ impedance magnitude is amazingly flat for a dynamic driver, running 15 ohms at all frequencies, and there’s very little electrical phase shift.
Sensitivity of the IE 300s, measured between 300Hz and 3kHz, using a 1mW signal calculated for 16 ohms rated impedance, is 103.1dB. That’s about 3dB lower than what I extrapolated from Sennheiser’s 1V RMS rating, but it’s high enough that the IE 300s should play quite loud from practically any source.
Bottom line: The Sennheiser IE 300 earphones’ frequency response is pretty weird in its near-complete lack of an upper-midrange peak. I loved the sound, but I sure wish I had access to a listening panel to get some other opinions.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, February 2021
I measured the Between Pros using laboratory-grade equipment: a GRAS Model 43AG ear/cheek simulator with the RA0402 high-resolution ear simulator with KB5000/KB5001 simulated pinnae, and a Audiomatica Clio 12 audio analyzer (recently upgraded from the Clio 10 FW I’ve been using since 2011). For isolation measurements, I used a laptop computer running TrueRTA software with an M-Audio MobilePre USB audio interface. An Mpow BH259A Bluetooth transmitter was used to send signals from the Clio 12 to the earphones. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed. Note that because of the latency introduced by Bluetooth, I wasn’t able to do a spectral-decay measurement, and of course my usual impedance and sensitivity measurements are irrelevant for wireless earphones. If you’d like to learn more about what our measurements mean, click here.
The above chart shows the Between Pros’ frequency response measured with the RA0402 ear simulator. This is a fairly standard-looking curve except for one thing: the lower-treble response peak is centered at about 3.8kHz, which is fairly high. Somewhere between 2 and 3kHz would be more typical. I suspect the relatively high frequency of this peak is what sometimes made voices sound a bit exaggerated in their upper harmonics. Note also that while Status Audio’s claims about the bass response are true—the rise in the bass occurs primarily below 200Hz—the bass bump is fairly high relative to the midrange, which would likely make these sound a little bassy. So the measurements (which were done after the review text was submitted) do reflect the earphones’ subjective audio characteristics, contrary to what dudes on the Internet who’ve never done an audio measurement in their lives may tell you.
The impulse response shows that the latency with the aptX-capable Mpow BH259A is 216ms, which is typical for the standard SBC codec, and higher than the roughly 120ms I would expect to measure with aptX. My guess is that the test sample I have was produced before the company added aptX and AAC.
This chart shows the Between Pros’ right-channel response compared with the EarFun Free and Technics EAH-AZ70W true wireless earphones, as well as with the AKG N5005s, the passive earphones said to best reflect the Harman curve. You can see that the Between Pros are pretty close to the Harman curve, with about 3dB more bass output on average, and about 5dB less output at 2kHz.
Fortunately, the new Clio 12 analyzer software can produce distortion measurements despite Bluetooth’s latency, so I no longer have to present the THD vs. frequency measurements as a Google chart. The Between Pros’ distortion is near zero at the loud level of 90dBA (measured with pink noise), and at the extremely loud level of 100dBA, reaches only about 2% in a small peak centered at 1kHz. So basically, these earphones can’t produce audible distortion, and unlike some true wireless models, they can reach 100dBA with pink noise.
This chart shows the Between Pros’ isolation versus three other true wireless earphones—the EarFun Free, the Grado GT220, and the Technics EAH-AZ70W (which have outstanding active noise canceling). The same slim, non-ear-filling design that makes the Between Pros so easy to seal securely in the ear canal also limits the amount of sound they can block below 1kHz, so these wouldn’t be a good choice for places where there’s lots of low-frequency noise, such as airplane cabins.
Bottom line: The Between Pro earphones have bit of a “smiley” (bass- and treble-boosted) response, but it’s pretty close to industry norms, and unless you want lots of isolation from external sounds, there’s nothing in the measurements that should give you pause.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, February 2021
I measured the Audeze Euclid earphones using laboratory-grade equipment: a GRAS Model 43AG ear/cheek simulator with the RA0402 high-resolution 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. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed. If you’d like to learn more about what our measurements mean, click here.
This chart shows the Euclids’ frequency response. This is mostly a “by the book” earphone response, except that the peak at 5kHz would usually be lower in magnitude than the peak at 2kHz, and the bass seems a little light relative to the upper mids and treble.
This chart shows how the Euclids’ 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, or some exotic tube amps. As expected with planar-magnetic drivers, whose impedance is almost entirely resistive, there’s very little difference.
This chart shows the Euclids’ right-channel response compared with Audeze’s iSine10 open-back earphones, the Meze Rai Pentas, and the AKG N5005s, which are said to be the earphones that come closest to the Harman curve target. Obviously, the Euclids are well within the range of normal—with a few dB less bass than the Harman curve, and more energy above 5kHz.
I learned a lot from the Euclids’ spectral-decay plot. I’ve seen that scattering of very high-Q resonances between 1 and 5kHz in most planar-magnetic drivers, and I always assumed it was caused by reflections between the large, flat planar driver and the flat metal “cheek” plate of the ear/cheek simulator. But here, the earphone is inserted straight into a steel coupler and the cheek plate is not used. So apparently, I was wrong—those narrow resonances are apparently inherent to planar-magnetic drivers, no matter what size they are. Anyway, I don’t know how audible they are; I suspect they may contribute an added sense of spaciousness.
It looks like Audeze’s 120dB claim for the Euclids’ max level isn’t so audacious after all. There’s basically no distortion at my normal test levels of 90dBA and 100dBA, measured with pink noise. I raised the level to 110dBA just to see what would happen, and all I got were a few narrow distortion spikes (up to around 2% THD) at 2.7, 4.4, and 6kHz. Using dBA with pink noise is a very conservative method of volume measurement; I’d guess that my 110dBA measurement was taken somewhere around the same level as Audeze’s 120dB measurement, which I’d guess was done with a 500Hz or 1kHz sine tone.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. The lower the lines, the better the isolation. The isolation of the Euclids is comparable to that of typical high-end earphones, and far better than you’ll get with Audeze’s open-back earphones (such as the iSine10 shown in the chart).
The Euclids’ impedance magnitude is dead flat at 13 ohms, and the phase is almost dead flat at 0°.
Sensitivity of the Euclids, measured between 300Hz and 3kHz, using a 1mW signal calculated for 12 ohms rated impedance, is 97.9dB. That’s about 7dB lower than Audeze’s rating, but still sensitive enough that the Euclids will play reasonably loud from a smartphone or tablet.
Bottom line: The Audeze Euclid earphones measure very well; I find nothing in the measurements that makes me question my very enthusiastic assessment of their sound.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, January 2021
I measured the Master & Dynamic MH40 headphones using laboratory-grade equipment: a GRAS 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. An Mpow BH259A Bluetooth transmitter was used to send signals from the Clio 10 FW to the headphones. For wired measurements, the headphones were amplified using a Musical Fidelity V-CAN amplifier. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed. If you’d like to learn more about what our measurements mean, click here.
This chart shows the MH40s’ frequency response in Bluetooth mode. The only really unusual thing here is that the peak near 3kHz is a few dB lower in magnitude than we might normally see, which suggests it’s unlikely these headphones will sound bright.
Bluetooth latency of the MH40s used with the Mpow BH259A transmitter is just 37ms, which suggests the headphones are equipped with aptX Low Latency or aptX Adaptive rather than just the standard version of aptX.
This chart shows how the MH40s’ tonal balance changes when they’re used in wired mode rather than Bluetooth mode. The shapes of the two curves are similar, but in wired mode you’ll get 3 to 4dB less bass and about 2dB more treble, so the sound will be thinner and brighter.
This chart shows the MH40s’ right-channel response compared with the AKG K371s’ response (headphones that come very close to the Harman curve response), the Marshall Monitor II A.N.C.s, in Bluetooth mode, and the Ultrasone Performance 880s with the Sirius Bluetooth adapter. You can see the relative weakness of the ~3kHz peak, but otherwise the MH40s are well within the realm of “normal.”
The MH40s’ spectral-decay plot (measured in wired mode) shows no significant resonances.
Even at the extremely loud level of 100dBA, the distortion (measured in wired mode) of the MH40s is insignificant.
In this chart, the external noise level is 85dB SPL, and numbers below that indicate the degree of attenuation of outside sounds. The lower the lines, the better the isolation. The isolation of the MH40s is comparable to that of typical passive on-ear and over-ear models. I threw in the Bose NC 700 headphones with noise canceling on so you can see how a model with excellent noise canceling would compare.
In wired model, the MH40s’ impedance magnitude is fairly flat, running between 18 and 20 ohms (although only about half the rated 32 ohms), and the impedance phase angle is also mostly flat.
Sensitivity of the MH40s in wired mode, measured between 300Hz and 3kHz, using a 1mW signal calculated for 32 ohms rated impedance, is 104.6dB, so any source device should be able to get plenty of volume from them in wired mode.
Bottom line: Other than a little less energy than expected around 3kHz, which will likely give the MH40s a somewhat mellow sound, this is a well-designed, well-built set of headphones.
. . . Brent Butterworth
brentb@soundstagenetwork.com
Reviewed on: SoundStage! Solo, January 2021
I measured the Grado GT220 earphones using laboratory-grade equipment: a GRAS 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. An Mpow BH259A Bluetooth transmitter was used to send signals from the Clio 10 FW to the earphones. These are “flat” measurements; no diffuse-field or free-field compensation curve was employed. Note that because of the latency introduced by Bluetooth, I wasn’t able to do a spectral-decay measurement, and of course my usual impedance and sensitivity measurements are irrelevant for wireless earphones. If you’d like to learn more about what our measurements mean, click here.
The above chart shows the GT220s’ frequency response measured with the RA0402 ear simulator. The bass is certainly extended and doesn’t seem attenuated from the measurement, but the high peaks at about 2.5 and 5.1kHz rise above the level of the bass, which is probably what makes the bass sound attenuated. Otherwise, the GR220s’ frequency response looks pretty much like the Harman curve with a deep midrange dip.
The impulse response shows that the latency with the Mpow BH259A is high, at 322ms. This surprises me, as the BH259A and the GT220s both have aptX, which in its standard version I’d expect to have latency in the low 100ms area. I have no way, with these devices, to confirm that aptX was actually activated when I did this measurement. If you get latency similar to what I got, the GT220s won’t be a great choice for watching videos, because you’ll likely notice lip-sync problems.
This chart shows the GT220s’ right-channel response compared with other true wireless earphones (Technics EAH-AZ70Ws and Soundcore Liberty 2 Pros), as well as with the AKG N5005s, the passive earphones said to best reflect the Harman curve. Again, the GT220s’ curve isn’t unusual except for its deep midrange dip.
Because of the latency of the Bluetooth connection, I could not use Clio’s sine sweep function to measure total harmonic distortion (THD) versus frequency, so I did discrete THD measurements of sine tones in one-octave steps. Distortion was almost non-existent at the loud level of 90dBA (measured with pink noise), but goes through the roof at the extremely loud level of 100dBA, reaching about 20% at 1kHz. (As always when I get such an anomalous result on this test, I tried it again, using a different amp and a completely fresh system calibration, but got the same result.) I did notice a few fleeting moments of distortion here and there in my listening, but nothing I thought worth including in the review. I think what’s happening here is that most true wireless earphones just don’t let you play loud enough to reach this level of distortion; many can’t even play loud enough for me to get a measurement at 100dBA. But Grado, as most makers of traditional audio gear do, gives the listener the option to push the gear a little past its limits.
This chart shows the GT220s’ isolation versus two other true wireless models—the HiFiMan TWS600 and the Technics EAH-AZ70W earphones (the latter having outstanding active noise canceling), plus the JVC HA-FW01 passive earphones. For earphones without active noise canceling, the GT220s perform about average on this test.
Bottom line: The GT220 earphones show a somewhat treble-heavy and mid-scooped tonal balance, which means they will sound somewhat thin, but the sound will have more apparent treble detail.
. . . Brent Butterworth
brentb@soundstagenetwork.com
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