64 Audio Duo Universal Dual Driver IEM Earphones
Usage Guide
Earphones
Our Hi-Fi specialists give free, honest advice — no commission, ever. Contact us by email or phone and we'll help you find the right cable for your system.
Item code: P002585
Inc. VAT (20%) · Ex. VAT: £999.17 Ex. VAT · Inc. VAT (20%):
Lowest price in the last 30 days:
Request to Price Match
If you've seen a better offer for this product, we will endeavour to match it. The competing offer must be on brand-new boxed items, and in stock from another UK Online Authorised Retailer (excluding marketplaces). Price match quotations are valid for 7 days.
SPEAKER CABLES:
A quantity of 2 means you will receive a pair of speaker cables e.g. for your front left and front right speakers. By entering a quantity of 1, you will get a cable for a single speaker e.g. centre speaker and this option also enables you to vary the length (and termination) of your cable for each speaker.
OTHER CABLES:
A quantity of 1 means you will receive a single cable in the case of aerial, satellite, subwoofer, digital coaxial & optical cables and a pair of cables in the case of 2 rca to 2 rca analogue audio cables.
NON-CABLE PRODUCTS:
A quantity of 1 means you will receive 1 of the specified products.
Order before 4pm (Mon–Fri) for same-day dispatch
64 Audio Duo Universal Dual Driver IEM Earphones
The 64 Audio Duo Universal Dual Driver IEM Earphones offer a unique audio experience with their semi-open back design, making them one of the world's only UIEMs with this feature. Equipped with the complete Tia System, Apex Core, Wave Sync, and LID, the Duo delivers 64 Audio's signature balanced sound in a revolutionary way. Designed to feel lightweight and unobtrusive, the Duo allows listeners to remain connected to their surroundings while being fully immersed in the music, thanks to its relaxed tonality and open air sensation.
The complex faceplate assembly of the Duo not only protects the IEM shell but also facilitates free airflow, contributing to its timeless and elegant design reminiscent of open-back over-ear headphones. With the Tia System, unwanted resonance and distortion are minimised, allowing the 9mm Dynamic Driver + Tia High Driver to radiate freely into the single large Tia bore without obstructions.
Additionally, the Apex Core technology enhances airflow, resulting in effortless music reproduction and minimal physical fatigue, while Wave Sync ensures coherence by introducing a crossover without changing the physical distance between the drivers.
What 64 Audio say
Duo is a two driver hybrid universal in-ear monitor (UIEM). Following Trió and Fourté, Duo is another fully tubeless design in our product range, with the added benefit of being one of the worlds only semi-open back UIEMs. Built with the complete Tia System, Apex Core, Wave Sync, and LID, Duo presents 64 Audio’s signature balanced sound in a whole new way. The simple audio design captures the listener’s auditory senses while forgetting they’re wearing IEMs in the first place.
The complex faceplate assembly not only serves an important role in protecting the shell of the IEM while allowing air to flow freely, it is also a major step in 64 Audio’s product design evolution. Duo is a timeless and elegant design reminiscent of open-back over-ear headphones.
Sound
Duo feels light, leaving your ears feeling open and relaxed even for long listening periods. You feel simultaneously connected to your physical surroundings while you’re enveloped by music. Relaxed tonality lets you put them on and get lost. It’s able to present a non-analytical top-end while retaining air and sizzle. The vast open air sensation supports an unobstructed soundstage with impactful centre imaging (unlike many other open back headphones) as well as no loss of bass. Duo effortlessly produces deep and rich low frequencies with plenty of sub bass.
Featured Technology
Rather than constricting the sound of the drivers by fitting a tube onto them, Duo’s complete Tia System reduces unwanted resonance and distortion by allowing the 9mm Dynamic Driver + Tia High Driver to radiate freely into the single large Tia bore with no obstructions to the front of the drivers.
Apex Core is a deeper understanding of air movement within an earphone system. Duo’s faceplate features a striking perforated grill that leaves the shell of the IEM open to the outside atmosphere for a less obstructed airflow resulting in an effortless reproduction of music and minimal physical fatigue.
Due to the high crossover point between the two drivers, Wave Sync was developed to ensure coherence; another industry first. By using a type of “all-pass” filter, we’re able to introduce a crossover while correcting for time without having to change the physical distance between the drivers.
Specification
- 1 tia High Driver – 1 Dynamic Low Driver
- 20hz – 20kHz Frequency Response
- 98 dB/mW Sensitivity
- Integrated 2-way passive crossover
- 9Ω Impedance
- -12dB isolation apex core technology
Black Premium Cable
- 0.23 Ohms Total Impedance
- 7 x 7 x 4 Multi-Twist
- Silver Plated OCC Copper Wire
- 26 AWG
- Terminated in 3.5mm
Included
- Duo Universal in-Ear Monitors
- 64 Audio Premium Leather Case
- TrueFidelity Foam Eartips (S,M,L)
- SpinFit Silicone Eartips (S,M,L)
- Silicone Eartips (S,M,L)
- Black Premium Cable
- Round Sticker
About 64 Audio
64 Audio is a family-driven company, comprising individuals who are mothers, fathers, sisters, brothers, musicians, and friends. With experiences spanning across oceans, career changes, and personal growth, they have remained united by the bonds of family and shared values. From sacrificing meals to pursuing entrepreneurial ventures, their journey has been defined by resilience and a commitment to those around them.
Their belief in the power of music to break down barriers drives their mission to redefine the world's connection with sound. By offering products that deliver music in its purest form, they aim to inspire both musicians and music enthusiasts to forge deeper connections with the music they love. Founded by Vitaliy Belonozhko, whose background as a sound engineer sparked the inception of 64 Audio, the company has evolved into a leading innovator in the in-ear monitor industry. With a dedicated team and a passion for excellence, 64 Audio continues to push the boundaries of audio technology.
About 64 Audio
Maker of custom and universal in-ear monitors, known for its tia drivers and Apex air pressure venting.
64 Audio makes in-ear monitors in two formats: universal-fit models you can use straight away, and custom models built to the shape of your ears. The company is American, and its catalogue runs from more accessible universals up to multi-driver flagships. You can choose by budget, fit preference and the way you listen.
Read more about 64 AudioShow less
The tia design uses an open driver layout
tia stands for Tubeless In-Ear Audio. 64 Audio says the design pairs open balanced armature drivers with a single large bore and tuned chambers, aimed at a wider soundstage and a smooth response. Not every model uses it, so check the product page for the one you are considering.
Apex vents pressure and sets isolation
Apex stands for air pressure exchange. 64 Audio says the vent relieves pressure in the ear canal to reduce listening fatigue. Replaceable isolation modules let you choose how much outside noise reaches you: the m20 module cuts 20dB, the m15 cuts 15dB and the mX cuts 10dB.
Custom and universal ranges sit side by side
The catalogue is divided into universal and custom ranges. Custom models are made from a digital scan of your ear and a 3D-printed shell, a process 64 Audio calls 3D-Fit. The company also names LID, short for linear impedance design, as a technology used across its multi-driver models.
Specification
- 1 tia High Driver – 1 Dynamic Low Driver
- 20hz – 20kHz Frequency Response
- 98 dB/mW Sensitivity
- Integrated 2-way passive crossover
- 9Ω Impedance
- -12dB isolation apex core technology
Black Premium Cable
- 0.23 Ohms Total Impedance
- 7 x 7 x 4 Multi-Twist
- Silver Plated OCC Copper Wire
- 26 AWG
- Terminated in 3.5mm
We use Royal Mail 1st Class services for our Standard Delivery.
Orders received before 4.30 pm Monday to Friday are usually dispatched the same day by FIRST CLASS post (unless premium postal or timed courier services are selected), subject to stock availability. This does not apply to custom-length cables and speaker cables as these require a longer timescale to terminate. This also excludes all cables selected for the burn-in service. Please note, we do not process orders on national holidays in the UK. Over 98% of our orders are delivered the next working day including Saturdays.
Standard delivery is usually within 2 working days, although 98% of all orders are delivered the next working day including Saturdays. In extreme cases, such as delivery to the Highlands and Islands, this may take 3 days.
All items are fully insured and come with an invoice from Future Shop. We use the Royal Mail for delivery of small packages and DPD Local or DHL for items that weigh over 2KG. Items over 2KG are fully insured and will usually be delivered within 48 hours of placing your order subject to stock availability. For international orders, we use FedEx or DHL services where customers have selected this option.








Please note, special orders for non-standard cable lengths may be subject to longer deliver time-scales. This may vary from manufacturer to manufacturer.
We offer 'Free delivery on orders over £99' subject to the following terms & conditions:
- Applies only to orders with £99 or more of items (including VAT at the UK rate), at Future Shop
- Free Delivery on orders over £99 utilises Royal Mail First Class postal service for items weighing under 2KG. For items weighing over 2KG, we use DPD or DHL next working day services which deliver from 9.00am to 6pm within mainland UK (excludes Royal Mail Special Delivery Services and timed next day delivery services by DPD or DHL).
- Applies only to deliveries to addresses within mainland UK and Northern Ireland addresses. Applies only to orders that are to be delivered to a single Mainland UK delivery address.
- You will not be eligible for free delivery on your order if any items are cancelled or returned for a refund, bringing the total order amount below £99. Where items are returned, the refund due will be the cost of the item less any postage costs.
- We reserve the right to change or discontinue 'Free delivery on orders over £99 promotion at any time.
- FREE DELIVERY FOR ORDERS OVER £99 OFFER DOES NOT APPLY TO TRADE CUSTOMERS.
UK Postal & Delivery Charges - FIRST CLASS
Free UK delivery on all orders over £99*
| Weight | Price (FIRST CLASS UK POSTAGE) |
| 0g - 1000g | £3.95 |
| 1000g - 1400g | £4.95 |
| 1400g - 1800g | £5.95 |
| 1800g - 2000g | £6.95 |
| 2000g - 3000g | £8.95 |
* Free Delivery on orders over £99 utilises Royal Mail First Class postal service for items weighing under 2KG. For items weighing over 2KG, we use DPD or DHL next working day services which deliver from 9.00am to 6pm within mainland UK.
Free Delivery for orders over £99 excludes Royal Mail Special Delivery Services and timed next day delivery services by DPD or DHL.
Special Delivery UK - Guaranteed Next Working Day
We have 99.9% of the UK covered With Royal Mail Next Day Special Delivery. We guarantee delivery to most UK addresses by 1pm the next working day. This includes Northern Ireland, Jersey and Guernsey. Some places take longer to deliver to but we still guarantee delivery within three working days by 5.30 PM.
Please note, Royal Mail Special Delivery for next working day may not be possible where non-standard cable lengths are ordered. If this is the case, the item will be shipped via The Royal Mail Special Delivery service as soon as the cable is custom made.
For orders weighing over 2KG, we reserve the right to ship items using Next Day Pre-Noon Courier Services where Royal Mail Special Delivery option has been selected.
Channel Islands & Northern Ireland
We accept orders from all Channel Islands including Alderney, Jersey, Guernsey and Sark. Unless you select a premium service, Items weighing under 2KG are delivered using our standard UK delivery option above. For items weighing over 2KG, a surcharge may be applied for all deliveries to the Channel Islands as well as Northern Ireland.
European Countries
Deliveries to EU member states are not subject to 20% VAT after December 31st 2020 and therefore the 20% VAT on items is automatically deducted when you log-in, register or proceed to place an order.
The customer will be liable for the VAT at the local VAT rate, duty on the import and the brokerage service fee if applicable. This may need to be paid in advance to your local Customs & Excise office or the delivery company before your order can be delivered.
We offer the following shipping services:
- Royal Mail First Class International Airmail Services - Items are usually delivered within 3 to 5 working days
- Royal Mail Standard International Mail Services - Items are usually delivered within 7-10 working days
- DHL Express International - Items are usually delivered within 24 to 48 hours. DHL orders must be received by 3:30pm for next day service to most destinations in Europe
- Federal Express International Priority - Items are usually delivered within 24 to 48 hours. FedEx orders must be received by 3.00pm for next day service to most destinations in Europe
- Federal Express International Economy - Item are usually delivered within 48 to 72 hours
We reserve the right to change your shipping method without notification if you select a method that we cannot use for your shipment (for instance, we cannot ship via postal services for items over 2 Kg to International destinations). If we need to change your shipping method, we will choose the least expensive shipping method for your order.
Worldwide - Excluding UK & Europe
Deliveries outside of the UK are not subject to 20% VAT and so the 20% tax on items is automatically deducted when you log-in, register or proceed to place an order.
If applicable, the customer will be liable for the taxes at the local tax rate, duty on the import and the brokerage service fee. This may need to be paid in advance to your local Customs & Excise office or the delivery company before your order can be delivered.
We offer the following shipping services:
- Royal Mail First Class International Airmail Services - Items are usually delivered within 7 to 10 working days
- Royal Mail Standard International Mail Services - Items are usually delivered within 15 working days
- DHL Express International - Items are usually delivered within 24 to 48 hours. DHL orders must be received by 3:30pm for next day service to most destinations in Europe
- Federal Express International Priority - Items are usually delivered within 48 hours. FedEx orders must be received by 3.00pm in order to ship items the same day, subject to stock availability
- Where the actual weight of the package significantly exceeds the shipping cost charged on orders, we may write to you for an additional shipping charge. For larger orders, items may be shipped in multiple packets at our discretion
We reserve the right to change your shipping method without notification if you select a method that we cannot use for your shipment (for instance, we cannot ship via postal services for items over 2 Kg to International destinations). If we need to change your shipping method, we will choose the least expensive shipping method for your order.