Reviewed on: SoundStage! Solo, October 2019
I measured the Simgot EK3 earphones 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. 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.
The above chart shows the EK3s’ frequency response measured in Strong Bass mode (the generally preferred mode of our listening panelists) with the Balanced eartips. This is a fairly ordinary result except for a couple of things. First, there are separate response peaks at 1.8 and 3kHz; normally we’d expect to see a single peak centered at about 2.8kHz. But that’s probably no big deal. The peak centered at about 6.8kHz is pretty common, although a little higher than typical. The only real issue here is the channel imbalance, with the right channel measuring about 2dB louder than the left from 150Hz to 4kHz. This result held up when I switched to using the cylindrical coupler that comes with the RA0402 instead of the full ear/cheek simulator. There’s a certain amount of uncertainty in earphone channel-balance measurements because of the slightly different response you see every time you remove and reinsert the earphone, but this is a pretty big difference, and suggests the factory QC process might stand improvement.
This chart shows the frequency response with in the EK3s’ different listening modes. I’ve doubled the dB resolution on this chart (to 5dB per major division rather than 10dB) so you can see the differences more easily. Note how close the Strong Bass mode is to the Bright Vocal mode, and how close the Exquisite Tone mode is to the Balanced Tuning mode. This shows that switch 2 has a large effect on the sound, but switch 1’s effect is small and perhaps could be considered superfluous.
The EK3s’ frequency response (shown in Strong Bass mode) changes a lot when you switch to a higher-impedance (in this case, 75 ohms) source device, such as a typical laptop or some professional headphone amps. Almost all balanced-armature earphones show some difference in response when switching from low- to high-impedance sources, but this is one of the biggest differences I can remember measuring. I’d strongly recommend using these earphones with a source device (preferably a portable music player or DAC-headphone amp) with output impedance of 5 ohms or lower.
This chart shows the EK3s’ right-channel response in Strong Bass mode compared with the Simgot EN700 Pros, Campfire Solarises, and AKG N5005s (the earphones said to best reflect the Harman curve) with their Reference filters installed. The similarity between the EK3s and the Solarises in this chart is interesting; the EN700 Pros are more like the AKG N5005s.
The EK3s’ spectral-decay (waterfall) plot shows a major, but well-damped, resonance centered at 6.5kHz. This resonance is high enough in magnitude and broad enough in bandwidth that I have to imagine it has some effect on the sound. There are also poorly damped but extremely high-Q (i.e., narrow) resonances at 6 and 12kHz, but these are so narrow and high in frequency that they’d be very unlikely to be audible. (If you’re curious, those are the fifth and sixth harmonics of the F# note at the second fret of the high E string on a guitar.)
Here you can see the EK3s’ total harmonic distortion (THD) versus frequency in Strong Bass mode; it’s fairly low for a balanced-armature model.
This chart pits the EK3s’ isolation versus several similar models, all fitted with silicone tips. Like most pinna-filling designs with over-ear cable routing, the EK3s’ isolation is pretty good, especially as the frequency rises past a couple hundred Hz, and assuming you get a good fit with whatever tips you’re using.
The impedance of the EK3s in Strong Bass mode shows large swings in magnitude and phase, which is why the earphones’ frequency response varies so much with high- and low-impedance sources.
This chart shows how the impedance magnitude of the EK3s changes with the different listening modes. The general shape of the impedance curve remains mostly the same, but switch 2 has a fairly large effect on the magnitude below 1.8kHz.
Sensitivity of the EK3s, measured between 300Hz and 3kHz, using a 1mW signal calculated for 16 ohms impedance (the rating is 14-18 ohms), is 116.2dB, one of the highest I have measured. That means the EK3s will play extremely loud from any source device, if you want them to.
. . . Brent Butterworth
brentb@soundstagenetwork.com