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Etymotic Research ER4XR Extended Response

Noise-isolating in-ear headphones

2 Reviews

Item # 255ER4XR

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Our take on the Etymotic Research ER4XR Extended Response

There's a lot of history behind the Etymotic Research ER4XR in-ear headphones. This is the latest generation of Etymotic's famed ER4-series earphones that debuted over 25 years ago. That original model carried a reputation of reproducing some of the cleanest, most-accurate sound ever heard. This "Extended Response" version has been tastefully tweaked to accentuate the low-end frequencies.

Eytmotic Research ER4XR earphones

The Etymotic Research ER4XR earphones offer superior noise isolation, clear sound, and strong bass.

An updated take on a timeless set of earphones 

There's a lot of history behind the Etymotic Research ER4XR in-ear headphones. This is the latest generation of Etymotic's famed ER4-series earphones that debuted over 25 years ago. That original model carried a reputation of reproducing some of the cleanest, most-accurate sound ever heard. This "Extended Response" version has been tastefully tweaked to accentuate the low-end frequencies.

Looking for a flat audio response?

The Etymotic Research ER4SR Studio Reference in-ear headphones have a more neutral sound signature. 

Top-notch noise isolation and transparent sound

To shut off outside noise and reduce vibration caused by airflow, you insert the ER4XRs deep into your ear canal. They fit like a pair of earplugs and block out 35-42dB of outside noise — some of the best noise isolation numbers I've ever seen. The tight seal also helps you get a stronger bass response.

Each metal earpiece houses a single balanced armature to deliver a clear sound across a wide frequency range. There is also a slight lift to the low-end. While your music will largely sound true to the recording, the bass boost resembles the extra action you'd hear from a set of speakers playing in a room — rather than an anechoic chamber. 

Durable design and customized fit 

The ER4XR in-ear headphones are solidly built and designed for portable use. Connect the 5-foot detachable,reinforced cable to your smartphone or portable music player and listen at home, work, or on the train. Just don't use them while you walk down the street — the noise isolation works so well it could be unsafe.

Etymotic includes five pairs of ear tips to ensure you get the best fit for your ears. You'll find three sizes of their triple-flange silicone tips and two sizes of their foam tips. All are designed to fit snugly and create an airtight seal for optimum bass response. 

Product Highlights:

  • in-ear headphones for accurate music listening with a little extra bass
  • single balanced armature drivers deliver transparent, natural sound
    • Extended Response version tuned for a slight low-end boost
    • left and right drivers matched to within 1 dB for better stereo imaging
  • offer 35-42dB of noise attenuation
    • deep, earplug-style fit greatly reduces outside noise
  • metal earpieces with anodized finish
  • detachable 5-foot braided, reinforced cable
  • includes five pairs of ear tips:
    • 3 sizes of triple-flange silicone tips
    • 2 sizes of foam tips
  • 1/4" adapter included
  • ACCUFilter™ replaceable filters protect drivers from ear wax
  • wax removal tool included
  • zippered carrying case
  • frequency response: 20-16,000 Hz
  • sensitivity: 104 dB
  • impedance: 45 ohms
  • warranty: 2 years
  • Our 60-day money-back guarantee

What's in the Box:

  • In-ear headphones with attached 60" cable (right-angled 3.5mm plug)
  • 3.5mm-to-1/4" Plug adapter
  • 4 Pairs of 3-flange ear tips (1 pair installed)
  • 2 Pairs of foam ear tips
  • 3 Pairs of ACCU-Filter wax filters (1 pair installed)
  • Filter removal tool
  • Clothing clip
  • User Manual
  • Certificate of Performance (in envelope)
  • "Important" sheet

Scratch & Dent items may be missing non-essential accessories. In some cases the manufacturer's accessories have been replaced with generic equivalents.


Etymotic Research ER4XR Extended Response Reviews

Average Customer Review(s):

(2 Reviews)
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Hands-on research

Features and Specs

Noise-canceling No
Bluetooth No
Mic For Taking Calls No
iPhone Control No
Lightning Connector No
Android Control No
Frequency Response 20-16k Hz
Sensitivity 98 dB
Impedance 45 Ohms
Weight 0.7 ounces
Cord Length 60"
1/4-inch Adapter Included Yes
Volume Control No
Parts Warranty 2 Years
Labor Warranty 2 Years

Product Research


Overview: The Etymotic Research ER4 MicroPro series of in-ear headphones utilize balance armature micro-drivers to deliver excellent sound quality. These reference-quality earphones deliver an unsurpassed 92%+ frequency response accuracy from 20 Hz to 16 kHz. A Performance Certificate is included with each pair of headphones to indicate the level of performance. The headphones come with a variety of ear tips for superb noise isolation, a plug adapter, a clothing clip, wax filters, and a zippered storage case.

ER4 Model Breakdown: There are two ER4 earphone models. This pair is the ER4XR which is Etymotic's new Extended Response earphone. The ER4XR's channels are matched within 1dB from 100Hz to 10kHz, and delivers a slight performance boost in the lower frequencies. The ER4SR Studio Reference earphone is much like the ER4XR, but offers a flat response across all frequencies.

Balanced-Armature Drivers: The ER4 earphones use high-performance, precision matched ACCU-Driver balanced-armature micro-drivers to achieve a 98 dB SPL sensitivity, and an 92%- response accuracy from 20 Hz to 16 kHz.

Noise Isolation: The ER4s have a closed-back design and noise-isolating ear tips to achieve a 98% reduction (35dB to 42dB) in ambient noise. The 3-flange silicone ear tips work with most sizes of ear canals to ensure a comfortable fit and a proper seal. The foam ear tips are heat-sensitive and will expand inside your ear canals to perfectly form to the contours of your ear to block out ambient noise. The earphones also come with an option for custom-fit earpieces.

Cable: The ER4 earphones have an attached 60" twisted cable with a right-angled 3.5mm plug. There is no in-line remote or microphone on this model. The cable attaches to the ear buds via a modified MMCX connector, making them removable and replaceable as needed.

ACCU-Filter: The Etymotic ER4 earphones are equipped with special ACCU-Filter wax filter to smooth the frequency response and prevent earwax from entering the earphones. The filters are placed at the end of the ear bud nozzle, and should be changed when they become clogged with ear wax. A filter removal tool is included in the package.


  • Frequency Response: 20Hz - 16kHz
  • Accuracy Score: 92%+
  • Impedance: 45 Ω (at 1 kHz)
  • Sensitivity: 98 dB SPL (at 1 kHz / 0.1v)
  • Maximum Output: 122 dB
  • Noise Isolation: 35-42 dB
  • Ear Bud Dimensions: Diameter 0.27" Depth 1.284"
  • Weight: 0.7 ounces

Our Product Research Team

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Q & A

Customer Q&A

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Why did you buy this?

Recommended by "the absolute sound" magazine. Bought to use with my Astell&Kern Hi-res player, AK Jr. [ Dale  Aug 29, 2017 ]