KATO

The Simgot metal 1DDs are all very comfortable. You have the EA500LM for a balanced, but somewhat aggressive v-shape, the original EA500 that's very bright and gets fatiguing quickly, but it probably has the biggest wow factor for the price. And the EA1000 might be just in your budget depending on sales/offers and is sort of a more refined EA500 that isn't as bright or fatiguing. The EA1000 is my overall favourite IEM, but the EA500LM is possibly a safer option for more people as it's the bassiest one, and although it also has more treble than the OG EA500, it's more balanced out by the bass and it doesn't sound as bright. The other notably good 1DDs are the Tanchjim ones, but their ergonomics are terrible. They're small, but have very bad fit stability. Also the Moondrop Kato, if you can find one, is a great all-rounder 1DD and very comfortable. But it's discontinued. The Kefine Delci is really comfortable, but it's a warm, laid back sort of tuning that's not really competitive with the $100+ stuff when it comes to resolution etc. If detail is your top priority, you aren't going to beat the EA1000. Also while it doesn't have as much bass as the EA500LM, it has more "kick" to it than any other IEM I've heard, and it is very *realistic* sounding bass, especially for acoustic drums.

I'm not sure what IEMs are going to be significantly lighter than the Kato. They're solid metal, but they're not *that* heavy. I carry mine around all the time. They're still one of the best all-rounder IEMs, fwiw. Maybe something from Aful, as they use resin shells? I don't think they're fully filled resin either, otherwise they'd be a bit heavier. Maybe something like the Performer 5+2. I have the original P5 and haven't heard the 5+2, but it gets quite good reviews. The Afuls all tend to be very comfortable as well. Most of the Tachjims AFAIK are metal as well and weigh about the same as the Kato. I have the Oxygen and it's a bit smaller than the Kato, but not noticeably lighter.

The weight normally helps them *not* fall out of your ears. My other "out and about" IEMs are the Ikko OH10 which is one of the heaviest IEMs in existence. It's basically a lump of solid copper, and quite a bit bigger than the Kato. That thing is super stable in the ears. Extra weight is only a problem if it's all on the outside of the IEM and tends to pull it out, like the 7Hz Sonus or Moondrop Stellaris. It's all about the centre of gravity being inside your concha, and ideally a bit towards the front so it will push itself towards your ear canal. If they're not stable in your ears then they might just not be going in deep enough. Maybe try other sizes of eartips. Or else you might just have quite small ears, in which case maybe something a bit thinner would be better, rather than something lighter. The Tanchjims are a bit smaller than the Kato, but I find them a bit less stable because they're too small to stay in place properly. In fact it could be that you have unusually large conchas, in which case a much larger IEM might be more stable. Also make sure the ear loops on the cable are supporting the weight properly so it's not just flopping around like it's loose. If they ear loops are too big then you can heat them up with a hair dryer and re-shape them to fit better. Hold in place until it cools down and repeat as needed.

I wouldn't say I've found one like that yet, but it's true that there's very little correlation between price and performance, at least in terms of what you like or don't like. Technical performance does tend to increase a bit with price, but also caps out well before you get into TotL stuff. Ironically, if you're very skilled with EQ and have the patience to dial everything in perfectly, some of the best IEMs to use as EQ platforms are some of the cheapest (Kiwi Ears Cadenza / KBear KB01 for instance). In terms of my collection, I probably spend more time listening to the QKZ HBB than any other single IEM and it's only $15. It's not the most technical IEM out there, but it's tuned to its limitations and does what it does really well, which is to be very warm-yet-natural sounding and easy to listen to for a long time. My most expensive IEM so far, the Variations, is one that I almost never listen to. Even though it's technically excellent, the tuning isn't my favourite (tucked midbass) and it's not very comfortable. My favourite IEM overall is the Simgot EA1000 which falls in the middle price-wise, but I wouldn't call it endgame because it's not perfect. It does however do some things other IEMs cannot do (at least none that I've heard), and at least keeps up with others in all areas. Comfort is another big, and often overlooked factor. And the interesting thing there is no only is there no correlation with price, if anything there's an inverse correlation. With the exception of Sennheiser, almost all IEMs get less comfortable as they go up in price, and the cheapest ones are the most comfortable because they're small 1DDs. I expect that when I do find something I would call "endgame", it'll probably be in the ~$300 price range, technically good, comfortable and stable in the ear, with a tuning that I just happen to like. It's entirely possible it will be a $50 1DD though because there's no technical reason why a well-tuned 1DD can't outperform kilobuck IEMs. Sennheiser's flagship kilobuck IEMs *are* 1DDs, they just put more effort than usual into tuning via 3D printing. There are already 1DDs around $50 with among the best drivers you can get, so cost of parts isn't the issue. It's more a question of when/if the market will start releasing such well-tuned IEMs at that price point. Most IEM pricing doesn't reflect the BOM cost at all, and may or may not reflect R&D investment. I also expect the EA1000 will be kept around for a long time because if you remove the imperfections, you most likely also remove what makes it so good. I expect I'll find something that I'll eventually like as much as the HBB but is better in every way. But so far I haven't, so there's a good chance that will stick around for a long time as well. If I had to get rid of my entire IEM collection and keep just one, it would, perhaps counter-intuitively, not be the EA1000. It would be the Moondrop Kato, which is actually slightly cheaper (but now discontinued). The thing about the Kato is it's just a really good all-rounder, that works for all genres of music, both indoors and outside where it's noisy, and has no issues with being listened to all day. The EA1000 easily beats it technically, but the Kato is just a bit warmer and overall I prefer a slightly warm tilt like the Kato to a cool tilt like the EA1000. I can still listen to the EA1000 all day too, but if you have a badly mastered track, the EA1000 *will not hide that fact at all*, whereas the Kato will lie to you a bit and just make it sound good.

*In theory* you can fix anything with EQ, but in practice you can't. Very fine-grained FR features will be almost if not completely impossible to correct with EQ because you can't rely on graphs and have to do it by ear, which is increasingly difficult to do the smaller the features are. The IEM is highly modal then it will be more reactive to whatever ear (or coupler) it's inserted into so ideally you want less of that. You also ideally want the IEM to be as well vented as possible for comfort reasons, but that can affect things like sub-bass extension, especially when BAs are being used to produce those frequencies. The other factor is pure extension and the absence of nulls. If the drivers can't generate sound past 10kHz, no amount of EQ is going to add those frequencies back in, at best it's going to either do nothing or add distortion. Most IEMs don't actually extend all the way to 20kHz, even though they often make nonsensical claims like 40kHz (which nobody could hear even if it were true). It's always possible to EQ down, but again if the response is very jaggy then it might not be possible to get it where you want it. Nulls are where you get certain frequencies cancelling each other out because of resonances, reflections, or phase issues in multi-driver IEMs. That will result in a dip in the FR that doesn't respond if you try to increase it with EQ, although if you do try, you risk accidentally introducing a peak right next to where you think the dip is. Here's a good video about how trying to EQ away narrow features can often end up making things sound worse, which is one of the main reasons why AutoEQ often doesn't work as well as expected: /r/headphones/comments/1ivy4u7/how_measurement_error_hurts_eq/ The general rule of thumb aside from "sounds good to me" is you want the FR to be as smooth as possible, and change as little as possible between different couplers. That way you are really only making HRTF accommodations & preference adjustments rather than trying to "fix" things. One issue about smooth graphs is that the ones you usually see, e.g., on squig.link, are smoothed (usually 1/3 octave I believe), which means there might be features you can't see. Like a slight dip in the FR could actually be a much narrower null, but when averaged out, it looks smoother than it is.

The crossover just determines which frequencies go to which driver(s), which in turn affects the final frequency response along with other things like acoustic tuning. Badly designed crossovers can cause things like nulls or other phase errors, which I mentioned earlier, can't be EQ'd away. This is why cheap hybrid IEMs are often bad, although the cost of a reasonably well-implemented hybrid has come down a lot in the last few years. That's one of the reasons a 1DD is typically better for EQ than most multi-driver IEMs, because there is no crossover to go wrong (and no possibility of phase errors between the drivers). Doesn't necessarily mean 1DDs are automatically better either. In the end, it's the end result that matters, which is almost entirely about the frequency response. That, alongside HpTF, distortion and time-dependent characteristics, although the last 2 are pretty much always below the audible threshold in IEMs, so there's no point in worrying about them most of the time. Having said that last thing, distortion is one of those characteristics that can't be controlled with EQ, so if it is audible, then it will make a difference. Crinacle actually put some thought into this in the design of the Daybreak, on the basis of "*if*you can hear it, it will sound better like this". He had said he intended to talk about it in the release video, but in the end it's only mentioned in passing, blink-and-you'll miss it sort of thing (I had to re-watch the video to see if it was mentioned at all). The thing about harmonic distortion is that even-order distortion tends to sound good, and odd-order distortion sounds bad. This contributes to why a lot of people like tube amps even though they're objectively bad. They add "good" distortion. Low levels of distortion that don't lead to clipping are typically referred to as "saturation" instead of distortion and are used a lot in mixing & mastering to make things sound fuller. That's another effect that can be added with DSP (not EQ but using the same sort of processing). But you can't *remove* distortion if it's being added by the IEM itself. As a generalism, distortion is always so low that it's not contributing anything to the sound anyway, but that may not have been the case 20 years ago, which may be where some of the myths about technicalities, and *physically* not being able to EQ them (as opposed to it just requiring a lot of skill), came from.