User Experience and Conclusion

Seen above is the right channel of the LETSHUOER EJ07M CIEMs placed into an artificial ear mold. I mentioned in all my previous IEM reviews how I have average-sized ears, and the ear mold above represents my own experiences well enough as a proxy. As such I surely had to take a photo of these in my own ear too. The phrase "fitting like a glove" came to mine but I'd rather say "fitting like a CIEM" going forward given how well these worked. I have also seen a few people recommend using hearing air lubricants such as Otoferm to help with the insertion and seal from CIEMs. The way you essentially insert these is by going in from the top and angling into the ear canal until you actually feel the seal in place. Do the same in reverse to extract it, and the see if you need the lubricant, which I ended up foregoing. The CIEMs will also seal better over the next few days as ear wax and your ear canals conform around them to make for, in an ideal scenario, near-perfect passive isolation that would compete against the best ANC solutions. Comfort should also be at the very top of the scale here, and I know people who sleep with CIEMs/ear plugs in the ears accordingly. The IEMs weigh ~8 g each here to where the larger size makes for relatively low density shells, which also reduce physical fatigue. I will also give a shout out to the angled 2-pin connector housings on the cable that allow for the pre-formed ear hooks to be more comfortably placed above and going around the back of the ears, for further support.


The LETSHUOER EJ07M CIEMs use the same drivers as the UIEM version in the form of a custom-to-LETSHUOER 10 mm nanocarbon-coated membrane diaphragm dynamic driver to handle the bass response, two Sonion 2389 balanced armature drivers for the middle frequencies, and four Sonion EST65QB02 electrostatic (electret) tweeter drivers for the high frequencies. It's a tribrid set thus, with a 1+2+4 configuration in a three-way crossover that has three tubes in the nozzle as we saw on the previous page. Driving the CIEMs should be comparable to the UIEMs too, in that it doesn't take a lot to get them going. It's more the testing part that required me to use blutack putty to essentially seal the CIEM nozzle inside my IEC711 couple as shown above. It's not a perfect solution but really it's impossible to accurately measure CIEMs unless you also make a custom coupler attachment based on your ear canals. Removing the stock attachment to couple the CIEMs directly to the mic capsule is possible with some CIEMs but my ear canals were too large to allow this to be done easily and instead made things worse. Testing was done as with any other IEM review thus, except without the use of the artificial ear mold.


Here is the average frequency response for both channels of the LETSHUOER EJ07M CIEMs plotted against my personal target, taken from VSG.squig.link, which also gives you an idea of my personal preferences to better correlate any possible biases. I also have the LETSHUOER EJ07M UIEM shown here for additional context and want to make it clear that the treble response is not dropping off with the CIEMs in practice. It's a measurement artifact and, if anything, I noticed the CIEMs to have further treble extension too! With the excellent fit and seal achieved in my ears, the LETSHUOER EJ07M CIEMs effectively dialed up all the good things about the UIEM version to 11, and I completely understood why so many people find this set their end game when it comes to the bass response in particular. Given I've already discussed how the UEIM version sounds and compares against others, I will simply stop here and point you to this page instead for more.