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64 Audio U4s 4-driver Universal In-ear Monitors , $1,199.00 - Add to Cart Skip to Product Information

64 Audio U4s 4-driver Universal In-ear Monitors

4-driver Hybrid Earphones with Dynamic LF Driver, Tia System, LID Technology, Apex Technology, and Electrical Lowpass Filter
64 Audio U4s 4-driver Universal In-ear Monitors
64 Audio U4s 4-driver Universal In-ear Monitors

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Only 8 left in stock! Order Soon!
Earphones Are Not Returnable
Sorry, earphones cannot be returned once opened, so please call if you'd like help choosing.
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64 Audio U4s 4-driver Universal In-ear Monitors
In Stock!

Only 8 left in stock! Order Soon!
Earphones Are Not Returnable
Sorry, earphones cannot be returned once opened, so please call if you'd like help choosing.

Hybrid Universal In-ears with Dynamic LF Driver

This article was Written By

Our Product Research Team

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The universal-fit counterpart to 64 Audio's custom-fit A4s, U4s is a 4-driver, hybrid in-ear monitor with a powerful Dynamic low-frequency driver. You'll enjoy resonance- and distortion-free listening, thanks to U4s's Tia system, while Apex tech supplies effortless audio reproduction and minimal wearing fatigue. LID technology ensures consistent sound regardless of what playback device you plug your earphones into. Moreover, you get a state-of-the-art lowpass filter that removes problem frequencies for even lower distortion. U4s offers a rich, enveloping listening experience that any musician will appreciate, along with a frequency response, detail, and soundstage that will please even the most discerning audiophiles. 64 Audio's U4s boasts an eye-grabbing look, with a Slate Blue shell color influenced by blue-dial timepieces, plus a unique faceplate pattern inspired by Muonionalusta meteorite fragments.

Distortion-free sound and long-wearing comfort

U4s delivers a first-class listening experience. Its Tia System minimizes unwanted resonances and distortion, delivering a transparent, lifelike sound. Its open-balanced armature Tia Drivers radiate freely into a single large Tia bore, resulting in zero obstructions to the front of the drivers. We're impressed by this design here at Sweetwater. It offers a significant step up compared to lesser designs that constrict the sound of their drivers by cramming them into a tube. Moreover, U4s's Apex tech employs a patented vent that releases air pressure in a sealed ear canal while maintaining isolation. This ensures less obstructed airflow, giving you ultra-clean audio and long-wearing comfort.

Consistent performance with any playback device

Armed with LID technology, 64 Audio's U4s accounts for the nonlinear impedances of the multiple driver sets comprising its 4-driver design. This factor ensures proper interaction regardless of what you plug into. Your source material will sound the same whether you're listening via smartphone, bodypack, or headphone amplifier.

State-of-the-art lowpass filter

U4s includes an electrical lowpass filter that lowers distortion by removing problem frequencies. This circuit actually eliminates target frequencies before they reach the IEM's driver. This filter isn't an old-school acoustic damper. Acoustic dampers are outmoded tech that don't actually prevent frequencies from hitting the driver; they merely keep them from reaching your ear. Acoustic dampers introduce unwanted vibration, air movement, and distortion at high volumes. Thanks to U4s's state-of-the-art lowpass filter, you won't encounter any of these issues.

64 Audio U4s Features:

  • Top-shelf universal-fit in-ear monitors with powerful Dynamic low-frequency driver
  • Tia system supplies resonance- and distortion-free listening
  • Apex tech ensures effortless audio reproduction and minimal wearing fatigue
  • LID technology ensures consistent sound regardless of playback device
  • State-of-the-art lowpass filter removes problem frequencies to lower distortion
  • Offers a frequency response, detail, and soundstage that will please even the most discerning of audiophiles
  • Boasts an eye-grabbing look with a Slate Blue shell and a faceplate pattern inspired by Muonionalusta meteorite fragments
  • Comes with TrueFidelity eartips (S,M,L), Silicone eartips (S,M,L), SpinFit eartips, an eartip holder, a silver-plated copper cable, m20 apex modules, m15 apex modules, mX apex modules, and a sticker

Warranty Info

Sweetwater's FREE 2-Year Total Confidence Coverage Warranty

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  • Save money with FREE parts and labor
  • Get back to making music with the industry's fastest turnaround time
  • Fix it the first time with our award-winning, factory-certified Service Department
Learn More about Total Confidence Coverage

Offer applies only to single-receipt qualifying purchases. Select manufacturers may require that only the manufacturer’s products qualify towards the minimum purchase amount needed to be eligible for promotional financing. Otherwise, an invoice that meets the minimum purchase amount and contains at least one qualifying manufacturer product is eligible for promotional financing. No interest will be charged on promo purchase balance, and equal monthly payments are required on promo purchase until it is paid in full. The payments equal the amount financed divided by the number of months in the promo period, rounded up to the next whole dollar. These payments may be higher than the payments that would be required if this purchase was a non-promo purchase. During the last month(s) of the promo period the required monthly payment may be reduced due to the prior months’ rounding. Regular account terms apply to non-promo purchases. New Accounts as of 07/31/2025: Purchase APR is 34.99%. Penalty APR is 39.99%. Min Interest Charge is $2. Existing cardholders: See your credit card agreement terms. Subject to credit approval.

Offer applies only to single-receipt qualifying purchases. No interest will be charged on the promo balance if you pay it off, in full, within the promo period. If you do not, interest will be charged on the promo balance from the purchase date. The required minimum monthly payments may or may not pay off the promo balance before the end of the promo period, depending on purchase amount, promo length and payment allocation. Regular account terms apply to non-promo purchases and, after promo period ends, to the promo balance. New Accounts as of 07/31/2025: Purchase APR is 34.99%. Penalty APR is 39.99%. Min Interest Charge is $2. Existing cardholders: See your credit card agreement terms. Subject to credit approval.

The estimated required monthly payment shown which excludes taxes and delivery equals the amount financed divided by the number of months in the promo period, rounded up to the next cent. During the last month(s) of the promo period the required monthly payment may be reduced due to this rounding. These payments apply only with the financing offer shown. If you make these payments by the due date each month, you should pay off this amount financed within the promo period, if it is the only balance you are paying off. If you have other balances on your account, this payment will be added to any other minimum monthly payments.

Applies only to select items from this manufacturer. Ask your Sweetwater Sales Engineer for more details.