The THIEAUDIO Monarch MKIV and Hisenior Mega5EST are two of the most talked-about tribrid in-ear monitors in the high-end segment. Both pack dynamic drivers, balanced armatures, and electrostatic tweeters into a single shell, but they aim at different listeners. The Monarch MKIV leans toward studio neutrality with a switchable bass boost, while the Mega5EST is tuned for musical enjoyment. Their headline scores are almost identical, so the choice comes down to what you value more: reference precision or everyday engagement.
Price and positioning
The THIEAUDIO Monarch MKIV is priced at $1149, putting it firmly in flagship territory. It is a ten-driver tribrid with dual 8mm dynamic drivers, six balanced armatures, and two electrostatic tweeters. The Hisenior Mega5EST costs $649, nearly half as much, and uses a five-driver tribrid setup: one dynamic driver, two balanced armatures, and two electrostatic drivers. That price gap is significant, and it shapes the entire comparison.
The Monarch MKIV was released in 2025, two years after the Mega5EST. The newer release brings a reference-grade tuning that Thieaudio describes as studio-neutral, with an extra bass-boost mode for those who want more low-end impact. The Mega5EST, from 2023, is described as cohesive and engaging, with a tuning aimed at broad appeal rather than clinical analysis. Both are wired IEMs; neither has Bluetooth, active noise cancellation, or a microphone.
If you are looking at either of these, you are already past the budget tier. The question is whether the Monarch MKIV's extra $500 buys you something you will actually use, or whether the Mega5EST gives you most of the experience for less. That is what the rest of this comparison tries to answer.
The scores, side by side
The HearWiki buyability score for the Monarch MKIV is 84/100. The Mega5EST also scores 84/100. That is a dead heat on the headline number. Neither is a clear winner there, and the rounded score hides only a fraction of a point between them. Both are highly recommended in their price class, and the score reflects published review consensus, price, and availability, not a weighted average of the sub-scores below.
On the sub-scores, the Monarch MKIV leads on sound with 9.4/10 versus 9.1/10 for the Mega5EST. That is close, but the Monarch's edge is real. The value sub-score tells a different story: the Mega5EST scores 8.3/10 while the Monarch sits at 7.6/10. Again, these are separate category summaries, not a formula, but the pattern is intuitive: the cheaper IEM offers more value per dollar.
Neither product has listed sub-scores for ANC, battery, or calls, because neither has active noise cancellation, a battery, or a microphone. Those fields are not listed for either product, so there is nothing to compare there.
Sound
The Monarch MKIV's sound sub-score of 9.4/10 is the highest in this comparison. Its tribrid configuration, with two dynamic drivers, six balanced armatures, and two electrostatic tweeters, is designed for clarity and detail. Published reviews describe it as reference-grade neutral with excellent clarity, and the electrostatic tweeters extend the treble without harshness. The switchable bass-boost mode adds flexibility, letting you move between a flat studio tuning and a more impactful low end. That makes the Monarch a tool for critical listening, but it also means it demands a capable source to perform at its best.
The Mega5EST's sound sub-score is 9.1/10, close enough that most listeners would need to A/B them to hear the difference. Its tuning is described as pleasure-oriented but balanced, with a cohesive presentation that is easy to listen to for long sessions. It is not trying to be a reference monitor; it is trying to make music sound good, and published reviews suggest it succeeds. The trade-off is that it does not offer the same level of technical precision as the Monarch, but it also does not require as much from your source.
If you want to dissect recordings and hear every micro-detail, the Monarch MKIV is the safer bet. If you want to put on an album and enjoy it without thinking about the gear, the Mega5EST is arguably the better daily companion. Neither is a wrong choice, but they are different philosophies.
Noise cancelling and battery
Neither the Monarch MKIV nor the Mega5EST has active noise cancellation. Both are wired IEMs, so they rely entirely on passive isolation from the ear tips and the shell. The Mega5EST is listed at 6 grams, which is light, and its shell is described as comfortable. The Monarch MKIV's weight is not listed, but its larger shell may not suit smaller ears, according to published reviews.
Battery life is not applicable to either product. They are wired, so there is no per-charge figure, no battery with case, and no wireless charging. If you need battery life, these are not the products for you. If you are comparing them to wireless earbuds, remember that neither offers any of the conveniences that come with a battery-powered design.
The Mega5EST is listed with a 25-ohm impedance, which is relatively easy to drive. The Monarch MKIV's impedance is not listed, but published reviews note that it requires a capable source. That suggests you should factor in the cost of a decent DAC or dongle if you go with the Monarch.
Calls and everyday use
Neither IEM has a microphone, so call quality is not a feature you can compare. Mic count is not listed for either product, and neither supports multipoint, transparency mode, or wear detection. These are pure listening devices, not communication tools.
For everyday use, the differences come down to fit and source requirements. The Mega5EST is lightweight at 6 grams and is described as comfortable, with a generous accessory set and quality cable. The Monarch MKIV is heavier on paper, though its exact weight is not listed, and its larger shell may be an issue for smaller ears. The Monarch also needs a good source to shine, which adds to its total cost of ownership.
The Mega5EST is the easier recommendation for someone who wants a premium IEM they can plug into a phone or laptop and enjoy. The Monarch is for someone who already has a dedicated setup and wants the last few percent of technical performance.
Which one should you buy?
If you are a critical listener who values reference tuning, detail retrieval, and the flexibility of a bass-boost switch, the THIEAUDIO Monarch MKIV is the one to get. It costs $1149, but it delivers a sound that published reviews place at the top of the wired IEM category. Be prepared to invest in a capable source and check that the shell fits your ears.
If you want a high-end tribrid that sounds great out of the box, is easy to drive, and costs $649, the Hisenior Mega5EST is the smarter buy. Its value sub-score of 8.3/10 reflects that. It is lighter, more comfortable for most people, and its tuning is designed to be enjoyable rather than analytical. With the headline scores tied, the extra $500 is hard to justify for most buyers.
There is no single winner here. There are two different answers to the same question: what do you want from a flagship IEM? The Monarch is a precision instrument. The Mega5EST is a musical companion. Choose accordingly.
For a full spec-by-spec breakdown, see the comparison table. You can also browse other wired IEMs or over-ear headphones if you are still deciding between form factors.
FAQ
Is the THIEAUDIO Monarch MKIV worth double the price of the Hisenior Mega5EST?
The Monarch costs $1149 and the Mega5EST costs $649, but their headline scores are tied at 84/100. The Monarch offers better technical precision and a switchable bass boost, while the Mega5EST gives you most of the experience for much less. If you are a critical listener with a good source, the Monarch is worth it. For most people, the Mega5EST is the better value.
Which IEM has better sound quality, the Monarch MKIV or the Mega5EST?
The Monarch MKIV has a sound sub-score of 9.4/10 versus 9.1/10 for the Mega5EST. That is a small but real edge for the Monarch, which is tuned for reference neutrality and detail. The Mega5EST is tuned for musical enjoyment and is easier to listen to for long sessions. Neither is objectively better; it depends on whether you prefer analytical or engaging sound.
Can I use the Monarch MKIV or Mega5EST for phone calls?
No. Neither IEM has a microphone, and mic count is not listed for either product. They are wired listening devices only, so you will need a separate headset or microphone for calls. If call quality is a priority, look at wireless earbuds instead, though neither of these products is designed for that use case.
