THIEAUDIO Monarch MKIV
2DD + 6BA + 2EST Flagship IEM
- Recommended for Audiophiles
- Recommended for Professionals
ForStudio monitoring/Critical listening/Gaming
- 2-4 working weeks for UIEM (default batches).
- 6-8 working weeks for UIEM with custom faceplate design
- No cancellation of UIEM (custom design) orders once ordered
Images are for reference only. Actual product and packaging may differ from the images. Final product is based on what is actually received.
Shipping time estimate. Pre-order items are non-cancellable and non-refundable.
Pre-order detailsRecommended products
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Optional pairings. A cable and ear tips are already in the box.
Overview
The details behind THIEAUDIO Monarch MKIV.
Flagship-level detail meets bone-rattling bass—custom-tuned at your fingertips.
Highlights
Customizable Dual Tuning Modes
Switch effortlessly between studio-neutral and basshead sound with the all-new tuning switch. Choose “STANDARD” for reference-grade clarity or activate “RUMBLE” to boost sub-bass by 3dB for deep, thunderous lows. It's two distinct listening experiences in one high-performance IEM.
IMPACT² Dual Subwoofer System
Powered by twin 8mm dynamic drivers in an isobaric chamber, IMPACT² delivers fast, punchy, and textured sub-bass with exceptional control. Enjoy powerful lows without sacrificing balance or precision, elevating your music with deep, clean impact.
T6 Aircraft Grade Aluminum Construction
The Monarch MKIV elevates its status by utilizing a premium T6 aluminum alloy shell. Precision CNC engineering achieves our most durable, yet lightweight, shell. Surface hardening also ensures more scratch resistance and corrosion resistance against sweat. Experience the fullness of your music with featherlight comfort in your ears.
Refined Treble with EST Drivers
Redesigned electrostatic drivers extend treble response to 40kHz while ensuring a smoother, more natural upper range. Improved crossover tuning delivers seamless transitions and airy soundstage, letting vocals and instruments shine with crystal clarity and realism.
THIEAUDIO
Custom Tuning at Your Fingertips
Switch between studio-neutral and basshead tunings whenever you want. For the first time in Thieaudio’s Signature Series lineup, the Monarch MKIV (Mark Four) comes with an adjustable tuning switch. Extensive R&D has led up to a functional tuning switch that is stylish, easy to use without tools, and makes an extensive impact on the tuning. Users can switch between “STANDARD” and “RUMBLE” modes. RUMBLE adds an additional 3dB to the entire sub-bass shelf, increasing both the sub-bass and low-mid power. With RUMBLE, the overall tuning profile becomes thicker, warmer, and more powerful. Monarch MKIV’s tuning switch allows users to enjoy both Monarch’s signature neutral tuning, while giving the option to experience the powerful bass slam like that of the Thieaudio Origin.
T6 Aircraft Grade Aluminum Construction
The Monarch MKIV elevates its status by utilizing a premium T6 aluminum alloy shell. Precision CNC engineering achieves our most durable, yet lightweight, shell. Surface hardening also ensures more scratch resistance and corrosion resistance against sweat. Experience the fullness of your music with featherlight comfort in your ears.
An All New Tuning Profile
The Monarch MKIV encompasses both tradition and modernity in its tuning profiles.
In STANDARD tuning mode, the MKIV goes back to its roots by bringing back a studio-neutral tonal balance. The sub-bass dishes out a whopping 10dB of hard hitting bass, but with a sharp 150Hz low-mid cutoff, the bass is fast and precise, allowing for a clean midrange. The midrange has been cleaned up to be more neutral between 150Hz and 1kHz, while the treble is more crisp and natural. Compared to the previous generation, the MKIV’s treble focuses more on vocal clarity while eliminating unnecessary upper treble harmonics for a smoother and more candid treble extension.
A closer look at THIEAUDIO Monarch MKIV.
The details, in full view.
In RUMBLE mode, the low-mid crossover is loosened, unleashing a more powerful bass and thicker mids. The sub-bass is boosted to 13dB to enable significantly greater thump and low-end presence. The low-mid range at 200Hz to 500Hz is also boosted by 2dB, giving greater body, depth, and texture to bass guitar, male vocals, and fundamental notes of instruments. RUMBLE is designed for those who love a thicker body in their music and want a more engaging bass.
The Monarch MKIV is meticulously tuned with 9 independent passive crossover components with a passive 4-way crossover network, 4 independent sound tubes, and impedance grounding network.
IMPACT2
The IMPACT2 (“Impact Squared”) is THIEAUDIO’s tried and true subwoofer solution consisting of two latest generation of 8mm composite diaphragm drivers arranged in an isobaric design. The new 8mm dynamic driver focuses on speed and hard-hitting slam for a powerful, yet clean sub-bass thump. The usage of two 8mm subwoofers significantly enhances the power and texture of the bass, while our in-house isobaric chamber design keeps the frequency and pressure constant. This means you can enjoy better quality bass without sacrificing tonal integrity.
Electrostatic Tweeters
The Monarch MKIV completely redesigns EST driver utilization. By more efficiently targeting the treble range of its balanced armature tweeters, the Monarch MKIV can focus the EST tweeters specifically at the 10-40kHz region. This new crossover technique allows smoother treble transition between the BA and EST drivers for a more natural treble timbre, while simultaneously enhancing EST output into the ultra-treble range. The result is a greater treble extension compared to previous generations while sounding smoother and more natural. Enjoy the spacious soundstage, clarity, and air in the sound - more comfortably.
Next Generation of Modular Cable System
The Monarch MKIV comes with the latest iteration of Thieaudio’s modular cable system: Chocolate. Consisting of thick 8 strands of ultra pure oxygen-free copper (OFC) wires and silver plated OFC wires, enjoy cleaner and more fuller audio transmission. The modular plug design allows users to switch between 4.4mm balanced and 3.5mm unbalanced plugs for integration with any audio device.
About THIEAUDIO
From a nameless group of DIY enthusiasts to one of the best acclaimed IEM brands in the world, THIEAUDIO has made an incredible journey in the pursuit of high-fidelity audio. THIEAUDIO has become a staple brand in audiophile communities around the world, beloved for its best-in-class tunings, superb technical performances, and budget-friendly pricing. From the start, the THIEAUDIO team has put audio quality at the forefront of each project, aiming to be the Robin Hood of the audio world by bringing the best sounding audio solutions at the most affordable prices. Since its launch in 2019, THIEAUDIO’s legacy of in-ear monitors has forever changed the world of IEM’s, influencing how global manufacturers of earphones engineer their products. THIEAUDIO’s international team of few, but dedicated engineers from China and South Korea are committed to continuing this legacy by creating innovative, yet affordable, audio solutions that will leave you in awe.
Sound profile
A closer look at the balance between bass, mids and treble.
- Balanced
- Tuning Meta
Technical details
- Driver configuration
- Tribrid
- Driver technology
- Dynamic Driver, Balanced Armature, Electrostatic
- Included plugs
- Interchangeable plugs
- Fit size
- Large
- Tuning profile
- Meta
- Sound color
- Balanced
- Suggested genres
- Vocal-focused music, Pop, Hip-Hop & Rap, Classical & Orchestral
- Driver
- 2DD (8mm) + 6 Sonion BA +2EST
- Crossover
- 4-way crossover with 4 sound tubes+2 ultra-high frequency drivers+4 high frequency drivers+2 mid frequency drivers+2 low frequency drivers
- Frequency Response
- 10Hz – 44kHz
- Impedance
- 10/9 ohms (±1 ohm) @1kHz
- Sensitivity
- 100dB ±1dB @1kHz
- Total Harmonic Distortion (THD)
- <1% @1kHz
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Expert reviews
Watch the review. Read the full story.
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Video review: THIEAUDIO Monarch MKIV
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Video review: THIEAUDIO Monarch MKIV
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Video review: THIEAUDIO Monarch MKIV
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Major HiFi
THIEAUDIO Monarch MKIV Review: Is This the Best Monarch Yet?
The review describes deep bass, organized imaging and smooth treble. The stage is relatively focused and studio-like rather than especially expansive.
Customer reviews
What listeners say about sound, fit and everyday use.
Your order
Which countries do you ship to?
We are generally able to ship to most countries via Express Shipping, and many countries via Standard Shipping. You may clarify this with our team to check whether Standard Shipping is available to your country.
We cannot ship to addresses that are "PO boxes or APO/FPO".
*Note: Generally, we can only do Selected Shipping to India and Russia. We can only do Express Shipping to Africa, Argentina, Hawaii, Kuwait, Mauritius, Montenegro and Sri Lanka, to name a few.
This may be subjected to changes due to unpredictable issues such as Covid, war, and etc.
How much does shipping cost?
We have two shipping methods - Standard Shipping and Express Shipping.
Standard Shipping is free for most countries, while Express Shipping is 15-35USD depending on your country. If your order is over 270USD, Express Shipping is free*.
*This applies for most countries. However, large items such as headphones and desktop DAC/AMPs (e.g. HarmonicDyne G200, MUSICIAN MDP-2, and etc.) are excluded.
Shipping fees exclude import taxes or processing fees that may be applicable for your country. Linsoul is not responsible for such fees. Should you refuse to pay the tax/customs fees, shipping fees will still be deducted from the amount paid for thetwo-way freightcharges. The cost of the freight charges may be more than the amount reflected on your order due to tax and other miscellaneous fees.
Some parcels claimed to be “returned to the seller” may be destroyed by the post office or customs officers when buyers refuse to accept their parcels or fail to pay for their taxes.No refundwill be processed for such cases.Standard Shipping via YunExpress is a tax-inclusive option for some countries. However, Linsoul will not be responsible for additional administrative or handling fees charged by your local courier company or customs. Please kindly check this with your local customs.For certain remote areas, there may be additional charges via Express Shipping. We will contact you if there is a need to make additional payments. Please contact us before placing an order, should you have any queries regarding shipping.
How long does it take to receive the order after it is placed?
For in-stock products, your order will be shipped within 3 working days. You may check with our staff regarding the in-stock status of any products.
Customized items will take a longer time. Please contact our staff for more information.
On normal non-sale days, once your parcel has been shipped out:
- For Standard Shipping, it takes about 2-4 weeks for items to be delivered after shipping out. For some countries, it might take up to 2-3 months, depending on your country, its customs and other factors.* The duration for transit is something beyond our control. Linsoul will not be making refunds for such cases. Please consider an upgrade to Express Shipping or keep the waiting time in mind.
- For Express Shipping, it takes about 3-7 days for items to be delivered after shipping out.
*Note: Timings might be affected due to festive seasons or other unforeseen circumstances
What happens if the parcel has been shipped but not delivered?
First, kindly contact your local courier using the local tracking number.
If your parcel were to be in transit for at least 3 months, it may have been lost in transit.
For orders below $50USD, you may either opt for a one-time reshipment of parcel OR a full refund of the amount paid in cash via PayPal/Credit/Debit card.
For orders above $50USD, we will only process a 50% refund of your order paid in cash via PayPal/Credit/Debit card. Should there be any concern about Standard Shipping, you are encouraged to opt for DHL Express Shipping instead.
Customers are to bear the consequences and fees incurred, if the parcel was undelivered due to any of the following situation:
- Wrong address or phone number provided by recipient
- Recipient was uncontactable when courier company contacted
- Refusal to sign for the package by recipient
- Lost or damaged parcel because recipient opted for “no-signature delivery”
- Refusal to pay for the local tax/processing fee by recipient
- Refusal to provide supporting documents for custom clearance by recipient
Who will pay for the import tax/custom fees
Customers have to bear any form of custom/import/processing fees that are applicable for your parcel.
Should you be unwilling to pay for the fees and reject the delivery of the parcel, you will still have to pay for the shipping cost. Linsoul will only refund the amount of your order after deducting the two-way shipping fees incurred.
What shipping companies do you use?
We collaborate with these courier companies:
- Standard Shipping: 4PX, UBI, NinjaVan, and Yun Express
- Express Shipping: DHL Express, FedEx and SF Express
How do I get help for my order?
Cancellation or/and modification of orders can only be done manually via our staff, provided that our Warehouse Team has not processed your order.
As our Support Team might not be available during non-working days and weekends, please place your order wisely.
Should you really need to cancel or/and modify your order after purchase, please contact us via our support email (Support@Linsoul.com) or website chat. We will help you with the changes if that could be done.
In general, upon receiving your parcel, please confirm the contents of the package and ensure that the package is in good condition before signing for it. All customers are strongly advised to take an unboxing video of their parcel and packaging when opening their parcels and products.
For faulty/missing items, please send an email to support@Linsoul.com for after-sale services. The following details are required.
- Send an email to support@Linsoul.com with an appropriate Subject Title
- Provide your order number and state the issue clearly
- Attach photos and videos to show that your product is faulty/missing. Shipping details on the parcel packaging have to be clearly visible.
If the photos/videos provided are insufficient to prove the stated issue, we will enquire more. Once the issue has been confirmed, we will arrange for a replacement, partial refund or a full refund (where applicable). For incorrect products, Linsoul reserves all rights in deciding whether you need to return the incorrect item or not. Please kindly contact us via email first. Our team aims to review your email within 3 working days.
For other queries, the fastest way to contact us is via our website or Discord
Linsoul Audio will not be responsible for parcels that have been damaged during the transit process.
Do I get tracking details for my order?
After placing an order, you will receive the order confirmation email. After your order has been shipped out, you will also receive a tracking email. You can track your order via the tracking number online. Should you not have received the emails or face any difficulties tracking your order, please kindly contact us for support.
For more than 1 orders placed under the same account and shipping address, Linsoul will automatically combine the orders and ship them out via one tracking number. Should you have special requests to have the orders shipped separately, please kindly contact us via Discord or our website's chat. We will do our best to help.
How do I cancel my order?
Cancellation or/and modification of orders can only be done manually via our staff, provided that our Warehouse Team has not processed your order. Orders that have been shipped cannot be cancelled and modified.
As our Support Team may not be available during non-working days and weekends, please place your order wisely as support cannot be guaranteed for such requests.
Should you really need to cancel or/and modify your order after purchase, please contact us via our support email (support@Linsoul.com) or website chat. We will help you with the changes if that could be done.
Can I return an opened item?
Request a return within 30 days of delivery while the product is factory-sealed. Contact support for instructions before returning anything.
Where should I send the product for the return process?
To initiate the return shipment, kindly send an email to support@Linsoul.com within 30 days upon receiving the sealed product(s). The RMA form and details will be provided to you via email.
When must the product be returned after receiving the RMA form and details?
After receiving the return instructions from us via email, kindly arrange the return shipment of the parcel within 5 working days, and update us with the tracking link via email again. Failure to do so will result in a cancellation of the return process.
When will I receive my refund after returning the product?
In most cases, after receiving and inspecting the returned product, your refund will be processed within 5 business days. Refunds may incur a currency exchange loss or transaction fee, depending on your source of payment (e.g. Bank or PayPal). Linsoul will not be responsible for such fees.
What warranty applies?
Most products come with a 1-year warranty; cables and accessories have shorter or separate terms.
Processing Time
This product is currently in its pre‑order period. Pre‑orders apply to items not yet in stock, and shipping will begin once they arrive. Processing times are estimates only.
Pre-order Period:
- 2-4 working weeks for UIEM (default batches).
- 6-8 working weeks for UIEM with custom faceplate design
- No cancellation of UIEM (custom design) orders once ordered
Images are for reference only. Actual product and packaging may differ from the images. Final product is based on what is actually received.
Note:
- No cancellation of orders once ordered.
- All orders to be shipped out sequentially.
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