Managed to get a pair of the Truthear Zero's for free(!) with an Amazon voucher deal. Plugged them into my smartphone and my first impression was, ok the (sub)bass on these isn't bad. I then remembered my phone doesn't have a very low output impedance and the Truthear have a stupidly low nominal impedance of just 10 ohms that rises considerably in the bass to sub-bass, so voltage division was likely meaning the bass was getting a boost. Btw I suspect this is one of the reasons for variation in reports of this IEM's bass,
even from the same person, so check the output impedance of your devices people before posting your impressions (and check cable resistance is approximately the same if changing them, as some IEM cables have ridiculously high resistance which will effectively add to the source output impedance.) And lo and behold, plugging the Truthear into my Qudelix 5K which has negligible output impedance, the (sub)bass was lacking. And the bass to mids transition isn't very cohesive, with a disconnected feel between them, likely due to the 'sub in an IEM!' gimmick, with the resultant mid-bass hump followed by a slight upper-bass dip and lower-midrange hump. It is a bit like listening to a 2.1 speaker system, but one with a mediocre subwoofer that doesn't actually extend that well down into the sub-bass, and lacking bass management so the bass doesn't correctly blend into the mids. And they're definitely pretty shouty, which just got more bothersome the longer I listened. Soundstage also isn't great compared to other IEMs. For stock sound I'd give them a 7.5 out of 10. Going back to the sound straight out of my phone, I actually preferred this overall, as at least that gave them some decent sub-bass (although it did result in the mid-bass rising a bit too high), which also flattened out the overall spectral tilt from the stock slight upwards tilt with frequency, and balanced out and somewhat masked the treble shoutniness. Out of my phone, I'd give the sound an 8/10, an improvement through pure output impedance luck and nothing more.
But the worst thing about them (apart from the covercringe) is the comfort...What were they thinking with that bore size? Did they design these for
Shrek? They're without doubt the most uncomfortable IEMs I've ever worn (with any of the provided tips), which just gets worse the longer you leave them in. Please, anyone whose first IEM this is, do not think they're all this uncomfortable and give up on trying any others based on them. After an hour of agony I was ready to pack them up and send them back (even for free they wouldn't be worth the pain), when I thought I'd see if I have any other tips lying around that might fit. Found some old cheapo Sennheiser IEMs and luckily their tips fit (and were very almost the same size as the Truthear ones so there should be minimal change in sound). Even better they improved the comfort significantly. Still not great, but good enough. So if anyone has any Sennheiser IEMs lying around, give their tips a go before shelling out silly amounts for some tiny bits of rubber to fix an ergonomic disaster of an IEM.
Overall, considering the abysmal comfort, ridiculously low non-flat impedance which can result in sound inconsistency across devices, disjointed bass with limited actual sub-bass despite the marketing and shouty treble design choices, I'd give them a 4/10. It's only through complete random chance that my phone's output impedance and some tips I had lying around elevates this up to a 7/10. Would I pay $50 for them? No way.
I actually also ordered the Sony MH1 (ancestor to the legendary MH755/MH750) and Etymotic ER2SE (can't be an audiophile without at least trying an Etymotic, right?*) to compare alongside the Truthears. The MH1 were such a relief after listening to the Truthears, in both comfort and sound. The treble was just so much smoother, never bothersome, somewhat subdued, but I'd prefer that over annoyingly shouty any day. And this is how you do sub-bass! The Truthears don't even come close in that department. Just goes to show you categorically do not need a separate 'subwoofer' in an IEM to get great sub-bass despite what Truthear's marketing tells you; a single driver can achieve this no problem. Anyone who thinks they've heard proper in-ear sub-bass please try to get your hands on an IEM without a front vent (and low bass distortion to boot) like the MH1/MH755/MH750 which create a completely airtight sealed front volume and so full pressure chamber conditions. The upper bass of the MH1 does bleed somewhat into the mids though (I actually find the cheaper MH755 better in this regard), so they do need a bit of EQ. After that they're amazing.
As for the ER2SE...absolutely awful. I don't know how anyone can think the Etymotic target (including other IEMs with or EQed to have anywhere near a similar response for that matter) sounds natural. After that initial reaction I thought I'd give them a second chance a day later. Nope, still sound terrible, thin with no bass or sub-bass, overemphasized upper midrange / lower treble, but simultaneously lacking in upper treble, and poor soundstage. Even EQed to Harman (my preference) they didn't sound great, likely due to their relatively high distortion compared to most other IEMs (even those costing a fraction of the price, with the even more expensive balanced armature models from Etymotic having higher distortion still), combined with the large increase in bass EQ they require pushing their distortion down there even higher. Then to top it all off, one of the earpieces developed a fault, randomly cutting out when the cable into it moved. After two days. Back they go. So much for paying for quality...My $5 MH755 I've had for years are still going strong with regular use. (Surprisingly the Etymotics weren't too bad in terms of comfort, nowhere near as uncomfortable as the Truthear with their stock tips anyway.)
So in terms of stock sound I'd rank all these IEMs like so: Sony MH755 > MH1 > Truthear Zero > Etymotic ER2SE. Which just so happens to be their ranking from cheapest to most expensive.
Sounds about right. And my impressions of the Sony's accords with blind listening tests:
https://www.reddit.com/r/oratory1990/comments/qyq99k/_/hmj71i2
Who'd have thought IEMs
tuned by a professional acoustic engineer who knows it's better to err on undershooting rather than overshooting their target (which btw is remarkably similar to Harman's, and came before the latter even published any of their research on headphone target response) around the frequencies our ears are most sensitive, would produce better IEMs than a YouTube reviewer? The Truthear's sound out of my phone would just come in second place behind the MH755, but that's complete random luck of the output impedance draw, and that along with randomly finding some more comfortable tips I had lying around are the only reasons I'm keeping them. (For my thoughts on EQs for the Truthear and the Harman in-ear target
see this thread.)
*Wrong. Don't bother.
