ER2XR (Extended Response) delivers impactful bass while keeping clear and accurate midrange and treble sound, using high performance dynamic drivers.
Etymotic ER2XR (Extended Response) is one of my favorite IEM from Etymotic that doesn't need any introduction. I bought this pair from a local shop around 2 years ago. It is a deep insertion micro dynamic driver design with almost ruler flat impedance across the audio band. And the most important feature is, it sounds pretty good.
Pros:ER2XR has 2 essential features for pro audio and on-stage applications:
- Very high passive noise isolation (35-42dB) from the deep insertion design. Essential as hearing protection for an on-stage performer.
- Close to ruler flat impedance (15 ohms) ensures consistent tonality with various audio equipment regardless of the headphone output impedance.
- Designed for deep insertion into the ear canal, may not be suitable for everyone.
- Very difficult to identify the Left and Right channels in a dimly lit environment. Very small black on black L/R sign on the Left and Right channels. There is no 'Left Dot' indicator on the Left channel connector.
- Total harmonic distortion is on the higher side of average THD from all the IEMs that I’ve measured.
- On tonality, to add a slight bump around the 4.5kHz treble area to improve perceived clarity, and to increase the overall upper treble response to improve perceived transparency and spaciousness.
- To add 'Left Dot' on the left channel connector for easy channel identification.
*EITC-2021 is my frequency response target curve. More info about it here.
*Note: When there is no obvious treble peak (T1p) around the 4-5kHz area, SPL at 4400Hz is used as T1p value.
Bass to mids tonality sounds good, clean, balanced, and pretty close to my perceived neutral. Treble is good but can be improved. Treble is a tad on the softer side of neutral and sounds very smooth. Sometimes with a certain recording, it may sound a tad dull for me. I prefer the treble area around 4-5 kHz to have a slight peak like the ER4XR, as it will improve the perceived clarity. And the upper Treble extension is also a bit too soft for my taste and slightly lack the perceived airiness and spaciousness.
Overall, it sounds quite natural and balanced but frequency extensions at both ends, sub-bass and upper-treble, sound a bit too soft. That’s the main reason I rate it 7/10. If ER2XR has a better-perceived frequency extension at both ends I will rate it higher on tonality.
Perceived detail and clarity are OK, but not great. It doesn't sound dull or muddy, just lacking a bit of transparency and airiness. Dynamic is quite decent with good and clean-sounding bass. Pretty good bass attack and impact but lack a bit of sub-bass rumble. Overall, I do like the sound quality of ER2XR.
Comparisons to Etymotic ER4XR and ER2SE:
The hump around the 5kHz could be the reason for the better-perceived clarity on ER4XR.
Equalization to Match EITC-2021One of the objective of my EITC-2021 target curve is that it is a realistically achievable target curve by my measurement equipment, based on the real measurement and not just as an estimated target curve. To really test and experience an IEM with matching frequency response to EITC-2021 sounds like, I created an equalizer profile for ER2XR to match EITC-2021.
EITC-2021 (Blue curve) and Etymotic ER2XR (Right channel) FR after equalization to match EITC-2021 target curve (Red curve):
To my ears, EITC-2021 equalization improves ER2XR perceived clarity and frequency extension at both ends. I use REW to create the equalizer profile based on the difference between ER2XR average response and EITC-2021. Then exported the equalizer profile as a text file to be loaded to Equalizer APO.
I attached the equalizer profile for ER2XR to match the EITC-2021 here, so anyone who would like to try EITC-2021 on their ER2XR can load it to Equalizer APO to test it. Please apply a -3dB gain to avoid clipping.
Disclaimer: The measurement results of the engineering quality measurement in this review represent only the pair of IEM that was measured for this review. It doesn’t represent the overall quality control of the factory.
Excellent left and right channel tracking. My unit has an overall 0.2-0.3dB matching from 20Hz-10kHz, with only 0.5 dB maximum at 5kHz.
The impedance curve is almost ruler flat, with only a shallow bump, around 0.5ohms increase at 2580Hz.
Overall THD level of the Etymotic ER2XR is a bit higher than most IEMs that I’ve measured. Please take note that distortion measurement is not part of sound quality evaluation. It is only used to observe the engineering quality of the IEM.
Distortion measurement at 94 dB SPL at 500Hz:
Distortion measurement at 104 dB SPL at 500Hz:
The following is my rating criteria:
Fit, Comfort, & Build QualityAll test is done using the ER2XR default medium triple flange ear tip. To me the fit and comfort are ok. The deep insertion design is surprisingly quite comfortable. What I mean is, I definitely feel something is stuck in my ear canal, but it doesn’t cause any pain. Even for a long session like an hour or more, I only need to readjust the position of the IEM a little bit every half an hour or so, but it doesn’t cause any discomfort until I must unplug it from my ears. I would say the level of comfort is around 7/10.
Build quality is generally good. I haven’t had any problem with the build quality. The cable is soft and flexible with sufficient thickness. The connector is custom MMCX so most 3rd party cables with MMCX won’t fit. Etymotic provided two spare green tuning filters (1500 Ohms) and the tool to replace it. Etymotic also sells a tuning kit for users to experience different FR with different tuning filters.
My biggest complaint is the left and right channel marking. It is almost impossible to see the marking in a dimly lit environment. The left dot as shown in the picture below has been implemented on many IEMs for many years, and I’m quite surprised why not all companies use this useful feature on their IEM cable.
Metal Shell to Ground Pin Connection: No connection
Recommendation:Suitable for applications where high level of noise isolation is important.
More information about my IEM Measurement Setup & Methodology:
Earfonia IEM Measurement Setup & Methodology
Advertised Technical Specifications:Frequency Response: 20 Hz – 16 kHz
Transducers: High performance moving coil dynamic driver
Noise Isolation: 35dB using silicone ear tips, 42dB using foam ear tips
Impedance: 15 Ohms @ 1kHz
Sensitivity: 96 dB @ 1kHz, 1mW
Maximum Output (SPL): 120 dB
Cable: Detachable 4 ft cable with MMCX connectors
User Replaceable ACCU-Filters: Yes
Warranty: 2 Years
Custom-Fit Option: Yes