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Etymotic Research ER4SR Studio Reference

Noise-isolating in-ear headphones

2 Reviews | 1 question - 1 answer

Item # 255ER4SR

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Our take on the Etymotic Research ER4SR Studio Reference

There's a lot of history behind the Etymotic Research ER4SR 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 "Studio Reference" version sports a modernized, durable design but still preserves that classic, neutral sound signature. 

Etymotic Research ER4SR earphones

The Etymotic Research ER4SR earphones offer superior noise isolation and a neutral, accurate sound.

An updated take on a timeless set of earphones 

There's a lot of history behind the Etymotic Research ER4SR 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 "Studio Reference" version sports a modernized, durable design but still preserves that classic, neutral sound signature. 

Looking for a little more bass?

The Etymotic Research ER4XR Extended Response in-ear headphones offer a slight lift in the low-end frequencies. 

Top-notch noise isolation and transparent sound

To shut off outside noise and reduce vibration caused by airflow, you insert the ER4SRs 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 more natural bass response.

Each metal earpiece houses a single balanced armature to deliver a clear sound across a wide frequency range. Your music will stay true to the recording — uncolored by any unnatural emphasis.

Durable design and customized fit 

The ER4SR 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 or studio monitoring
  • single balanced armature drivers deliver transparent, natural sound
    • Studio Reference version tuned for neutral sound
    • 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

Etymotic Research ER4SR Studio Reference Reviews

Average Customer Review(s):

(2 Reviews)

Remarkable Aural Picture

JD from San Antonio, TX on 1/8/2018

Crutchfield Customer Review (What's this?)

Upgraded from Audio Technica wired ear buds to these, and the difference is incomparable. Verbal clarity is almost perfect and the sound stage is huge. I listened to Tom Wait's Mule Variations in FLAC and found the sound to be nearly overwhelming, so much to hear and such resonant tonality and presence.

Pros: Clarity, excellent recreation of live experience.

Cons: If you want big bass, this isn't the set for you; try the similar ER4XR.

Not kidding about "studio reference"

Ed from White House Station, NJ on 8/10/2017

Crutchfield Customer Review (What's this?)

Etymotic just don't get the love they deserve, maybe because they've been around so long. The ER4SR are EXCELLENT, the best Etys I've owned, and I've had one set or another back to the 1990s. I've got two sets of their earphones with the mic on them, and they sound great, good enough for listening in transit, but these are captivating. As in, if I was on my way to work I might not get there because I might get so deep into listening that I just stop and stand and listen. Clear and precise. Totally spooky good when listening to binaural recordings - sounds that came from behind during the recording make me instinctively look behind me. I own a couple pairs of custom IEMs that I paid 4-5x the list price of the ER4SR. They're not better - different, yes. One set is more bass tilted, another is a bit brighter. These are just dead on precise. You're IN the music. BTW - I STRONGLY recommend getting custom tips made, any audiologist can do that for you. They'll then fit flawlessly, not generically. They'll isolate more, and sound better because there'll be a perfect seal. I have a couple sets of custom tips for Ety's balanced armature designs (I have weirdly shaped ear canals) going back to YEARS ago, and just move them to new ones if I break a set. (Or a puppy does... happened twice, thankfully not with the expensive Etys.) Worth owning. For a bit more money, custom tips, and you'll be blown away for a fraction of CIEM costs.

Pros: Cheaper than CIEMs of equivalent sound quality; can have custom tips made; flawlessly accurate reference quality sound; phenomenal isolation even with generic tips.

Cons: Little clip thing won't stay on; tangle easily if you don't put them away right; longer cord than I like; misbehaving puppies like to chomp Ety earphones.


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

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team. They verify what’s in the box, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Q & A

Customer Q&A

1 question already asked

These headphones come packaged with 6 different eartips (4 pairs of "3-flange" & 2 pairs of foam) so, yes, with the proper sized pair for your ears, you can wear these headphones for long periods without discomfort. I hope that helps. My Bio: [ Ryan  Sep 06, 2017 ]  Staff