Introduction

If you’re reading this buyer’s guide, you’re likely deep into the IEM game. I won’t bore you too much with an elaborate introduction. This buyer’s guide will showcase some of the best IEMs I think are worth listening to in your search for the coveted endgame IEM - consider these curated suggestions rather than definitive picks.

But for those less familiar with high-end IEMs and are doing a little bit of window shopping, let me be the first to say that IEMs are very much luxury products. The deeper you venture into the luxury market, the question of value becomes increasingly difficult to answer. That economic “willingness to pay” curve shifts dramatically as customers prioritize different aspects of a product’s quality - sound, comfort, uniqueness, to name a few. 

In this price range, diminishing returns are near their peak, but so is the challenge to find that few drops of performance that synergize with your music and preferences. This is for those who love the audio journey - the discovery of unique acoustic signatures, appreciating driver implementations, or simply owning a piece of sonic art - all of this justifies the investment.

This guide was written by Fc-Construct with input from the rest of the Headphones.com reviewer team. The team does not receive any form of compensation from any of these recommendations. Current prices may differ from listed due to shifting market conditions.

64 Audio U4s - $1,100

The U4s is 64 Audio’s most affordable universal IEM. But don’t let the price tag fool you. In many respects, the U4s usurps its older brother, the Nio, while maintaining the classic, 64 Audio house sound. The U4s is tuned in a U-shaped fashion with a strong emphasis on sub-bass and upper-treble for an exciting yet controlled sound. The addition of a dynamic driver completes what some might affectionately describe as a “baby U12t with a DD”. 

Of course, no IEM is perfect and some listeners might be predisposed to find issues with the more reserved upper-midrange tuning or find the U4s too bright. But the addition of three APEX modules (swappable modules that control the level of bass) offers the potential for plenty of fine-tuning. With the variety of options in today’s market, it’s hard to say if the 64 Audio U4s is the best option. But it remains one of the first recommendations for anyone looking for something in the kilobuck range. 

Precogvision’s written and video review | Read Fc-Construct’s impressions vs the Nio

Honorable Mention: 64 Audio U6t - $1,300

A slightly more expensive alternative to the U4s is its all-BA older brother, the U6t. It falls behind (arguably) on technical ability, but comes with a tonality that may be more preferable to others. Compared to the U4s, it relaxes the U-shaped features - tamer bass and milder treble. The U4s gets the nod over the U6t given its cheaper price tag and more vivid qualities, but if you’re looking for a warmer, steadier sound, the U6t is a rock-solid choice.

Read Precogvision's review | Read Fc-Construct’s and Resolve's dual review

Symphonium Helios - $1,100

The Helios is an IEM for listeners who like their IEM to demand attention. The Helios has a classic neutral-bright signature. Its presentation is clean with a slight upper-midrange emphasis and a (better than) class-leading treble response. That said, it does have a bit of disjointed feel in the mid-bass/lower-mids transition due to a 200 Hz recession. Beyond that, the Helios has almost zero weaknesses in the technical department: sharp leading edges to notes, notable micro-contrast, and incisive, slightly out-of-head imaging. The only thing that holds us back from unequivocally recommending the Helios is its fit - it’s just a little too large for some ears. But if you can get around that, the Helios is one of the best sounding reference-style IEMs for the price.

Read Fc-Construct’s review | Read Precogvision’s review

Thieaudio Monarch MKIV - $1,150

Thieaudio’s Monarch IEM line-up is possibly the most recognizable name at the $1,000 mark. The MKIV represents their latest entry, now tuned to the “New Meta” style. But that’s not all - it features an effective bass switch for a borderline basshead experience. Two in one!

The Monarch MKIV is a slightly leaner take on the “New Meta”, with a little more forwardness in the upper mids and treble that doesn’t overstep any boundaries. This makes the MKIV have a focused, more analytical sound. Resolution and imaging are top notch. If you’re looking for those perceived technicalities, the MKIV is one of the best at the $1,000 or so mark. That said, there is an element of “dryness” to this IEM. It’s very good, but somehow arguably not quite as musically engaging as some of the other options on this list. The bass switch helps a little with that enjoyment, but doesn’t completely resolve it.

 

Read Fc-Construct review

Nightjar Singularity - $1,300

The Nightjar Singularity asks the question: what happens when you take a superbly well-tuned single dynamic driver IEM and add bass to it? A lot, a lot of bass. This is an IEM for bassheads that don’t want to compromise on timbral performance. And there’s nothing else to it; the Singularity is a pure, single-minded IEM. While it won’t have the final word in any technical parameter, it puts on a satisfactory performance that doesn’t detract from its main mission of delivering bass. The only nitpick to its bass is a pillowyness in its impact.

Read Fc-Construct’s review

Sennheiser IE900 - $1,500

Sennheiser is a legendary name in audio. But unlike their pedigree in headphones, they’ve struggled to find relevance in the modern IEM landscape. Enter the IE 900. Sennheiser’s return to the high-end market was marked with arguably one of the best single dynamic driver IEM out there. The raw quality of its bass, its dynamics and power, easily competes at the highest level. To contrast all of this bass energy, the IE900 has a significant amount of mid-treble elevation. Yet Sennheiser, through meticulous research and design, has managed to do what many companies can only dream of: a bright, lively treble that doesn’t compromise on control. Overall, the IE900 has a vivid U-shaped that’s made for immersion. Unfortunately, the IE900 is not perfect. Namely, its upper midrange structure has an awkward recession that compromises vocal performance. Furthermore, the IE900 doesn’t quite hold up to the U4s or Helios when it comes to resolution or imaging.

While the IE900 won’t be the first choice, it’s definitely one of the best “flavor” IEMs to have in your collection, particularly if you’re open to EQing the midrange. Between the authors of this recommendation, Precogvision has owned one. Fc-Construct is sorely tempted.

Read Precogvision’s review | Read Fc-Construct's review

 

Symphonium Crimson - $1,500

Like the Helios, the Crimson is an intense sounding IEM. The bass response of the Crimson is incisive like only BA bass can be, yet more impactful than it has any right to be for BA bass. The upper midrange of the Crimson is forward as can be with an aggressive edge. The biggest point of contention would be the Crimson’s treble response, where it may come off as excessively sharp. This is an IEM that benefits from tip swapping. 

Overall, the Crimson’s sound is highly colored yet undoubtedly delivers when it comes to technicalities too. In particular, the sense of dynamics it is able to deliver might be the gold standard for its price point. The Crimson is a slap in the face to common driver stereotypes and performs far beyond what anyone might expect a BA IEM to deliver.

Read Precogvision’s review | Read Listener’s review | Watch Resolve’s review

64 Audio U12t - $2,000

It had to make the list. The 64 Audio U12t remains one of our favorite IEMs, and it’s made its mark in the audio community as the perennial flagship benchmark. The U12t really makes so few mistakes thanks to its slightly warm, yet clean tonality with a touch of spice up top in the upper-treble. And it's no technical slouch either, from its superb BA bass, impactful center imaging, and authoritative macro-dynamics. Listeners seeking a more forward sound, particularly in the upper-midrange, might be suited elsewhere, but it’s difficult to go wrong with the U12t. It's for these reasons that the U12t is the first IEM that’s often recommended to anyone with an abundance of money to spend and isn’t exactly sure of what they want.

Read Fc-Construct’s review | Read Precogvision’s review | Read Resolve’s review | Watch Goldensound’s review

Thieaudio Valhalla - $2,000

After years of dominating the more budget IEM market, Chinese brands have started to expand into high-end IEMs. The Valhalla is Thieaudio’s flagship product and their proclamation that they can compete at the highest end.

In many ways, the Valhalla is the Chinese analog to the U12t. Both IEMs come in at $2,000. Both IEMs have exceptional technical performance. Both IEMs are well-tuned to be engaging without straying too far outside of balanced. Like the U12t, the Valhalla delivers a shockingly deep, impactful bass response with its 19 BAs. Its treble is largely downsloping, with the exception of a bright spot in the upper treble. This gives the Valhalla an overall focused, denser sound in the lower frequencies without losing a step in agility and articulation. The biggest complaint you’ll find about them is the size of its titanium shells.

Read Fc-Construct’s review

Conclusion

You might have noticed that a number of the IEMs in this list feature tonal balances that don’t follow common preferences. These eccentric tunings may be polarizing, and that’s no coincidence. Beyond tonal preferences, these unconventional designs of boutique IEMs can sometimes offer certain perceived technical qualities (such as resolution, imaging, and soundstage) that might otherwise be limited in more traditional tunings. Like many luxury products, these IEMs are meant to appeal to a very specific set of customers. While there aren't many of them, these customers exist. And the IEM space is made better for it.

More Resources

If you’re completely new to the audio hobby or in-ear monitors and still have questions, here are a few important resources to give you a foundation of what reviewers talk about in this hobby.

The ABSOLUTE Beginner's Guide to IEMs - Everything You Need to Know in Less than 10 Minutes

Watch the video  

A Reviewer's Guide to Understanding Graphs - the B&K 5128 Edition

Don't Buy Headphones Until You Watch This

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What is a DAC and why do you need one?

Watch the video  

What does an amplifier actually do?

Watch the video  

Sound quality in headphones explained

Watch the video