Here's an interesting experiment that I just tried, because of a PM, asking how my LZ A4 earphone compares to my NiceHCK EBX earbud.
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Since they've both got MMCX connectors, I've currently got an EBX (donut foam over full foam) in my left ear, and an A4 (Grey Nozzle, Red Back) in my right ear (it's the Left earphone, since it's more comfortable to switch them, when worn over-the-ear).
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I've listened to them connected to the Balanced output on my Walnut F1 Amp, with input from a FiiO Taishan D03K (Cirrus 4344) DAC, being driven by the TOSLINK output of my Roku 4 Net Streamer (streaming music from the Internet) - and to the Balanced output on my Onkyo DP-X1 DAP (playing FLAC files of my CD rips).
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Surprise - The EBX goes as low in the Bass, but doesn't have quite as much impact, since it's not sealed in my ear, like the A4.
The EBX does seem to be more efficient (louder), and it may have a bit more Midrange.
So, the whole sound image is shifted a bit to my left, since the EBX has a bigger, more open Sound Stage, and the A4 is a bit more in-your-head sounding.
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Other than that, they sound very similar. (NOTE: My hearing only goes out to about 13.5-KHz, so I'm not hearing any differences in high frequency peaks.)
EDIT:
Just realized that I had switched from the Grey Nozzles to the Black Nozzles - so the EBX really does have more Midrange (above 1.5-KHz).
Using the Green or Blue Nozzles, might even up the levels between the A4 and the EBX.