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