Quick answer

Choose the ER3SE if you want the highest-sensitivity single-driver Etymotic in-ear monitor and want to spend less. Choose the ER4SR if you want the highest-performing single-driver model and value its reinforced, twisted replaceable cable. Both use a single balanced armature driver in a slim CNC-machined anodized aluminum shell, so the real decision is sensitivity and cable versus outright performance.

What actually separates the ER3SE and ER4SR

Etymotic builds both models around a single balanced armature driver. That design avoids crossovers, which keeps the aluminum body small and slim and supports the accurate, flat response the ER series is known for. The ER3SE is positioned as the highest-sensitivity single driver in-ear monitor, while the ER4SR is positioned as the highest-performing single driver in-ear monitor.

The ER3SE ships with a user-replaceable cable. The ER4SR ships with a high-quality user-replaceable cable that is reinforced and twisted to improve durability. If you handle your earphones carefully and mostly listen at a desk, that cable difference may not matter much. If you coil and uncoil your cable daily or commute with it, the ER4SR's cable is the more reassuring choice.

How to read the price gap

At catalog prices, the ER3SE is listed at USD 162.49 against a comparison price of USD 249.99, and the ER4SR is listed at USD 265.99 against a comparison price of USD 379.99. The ER4SR costs roughly a hundred dollars more at these prices.

That gap buys you the highest-performing single-driver designation and the reinforced twisted cable. It does not buy you a different driver count, a different shell material, or a different fit system. If those are the features you care about, the ER3SE already covers them, and the savings can go toward spare foam eartips or damper filters.

Damper filters and eartips change both models

Because both earphones use the same ER-series fit and accessory ecosystem, you can tune either one after purchase. The Damper Filters with Removal Tool 4 Pack changes the acoustic resistance inside the earphone, subtly shaping the sound to suit your hearing. Age, ear shape, and hearing damage all affect how you perceive music, so this is a practical way to personalize a flat response earphone rather than replacing it.

The ER38-14F Standard Black Foam Eartips come in a five-pair pack and fit the ER3 and ER4 among other models. Foam tips seal differently than silicone or flange tips, and seal quality drives bass perception more than most people expect. If you audition both earphones, test them with the same tip type before deciding.

Trade-offs to weigh before you buy

  • Sensitivity vs. ultimate performance: The ER3SE is the highest-sensitivity single-driver model, so it reaches usable volume more easily from laptops and phones. The ER4SR is the highest-performing single-driver model, which favors listeners chasing the last degree of accuracy. Pick ER3SE for easy driveability; pick ER4SR for the top single-driver designation.
  • Cable durability: Both cables are user-replaceable, but the ER4SR's is reinforced and twisted, while the ER3SE's is not described that way. Frequent travelers and daily coilers should lean ER4SR.
  • Price difference: The ER3SE is listed at USD 162.49 and the ER4SR at USD 265.99 at catalog prices, so the ER4SR costs about a hundred dollars more. Decide whether the performance and cable upgrades justify that gap for your own use.

Product facts at a glance

  • ER3SE Earphones: ER3SE is the highest-sensitivity single driver in-ear monitor, with anodized aluminum shells CNC machined to tight tolerances and a user-replaceable cable. Higher sensitivity means the ER3SE is easier to drive from modest sources, and the slim aluminum body plus replaceable cable keeps long-term ownership practical.
  • ER4SR Earphones: ER4SR is the highest-performing single driver in-ear monitor, with anodized aluminum shells CNC machined to tight tolerances and a high-quality reinforced, twisted user-replaceable cable. The ER4SR is the pick when maximum single-driver performance and a more durable cable matter more than saving money.
  • Damper Filters with Removal Tool | 4 Pack: Damper filters change the acoustic resistance inside the earphone to subtly shape the sound, and the set includes a removal tool. Lets you adjust either earphone to your own hearing instead of accepting a fixed tuning.
  • ER38-14F Standard Black Foam Eartips - 5 Pair: Standard black foam eartips come in a five-pair pack and fit the ER3 and ER4 series. A reliable seal is the single biggest factor in what you actually hear, so keeping spare foam tips on hand protects your comparison test.

Which one should you buy?

Best for

  • Listeners who want the highest-sensitivity single-driver Etymotic and want to spend less
  • Buyers who plan to tune their earphones with damper filters and foam eartips
  • Desk or studio listeners who do not need a reinforced twisted cable

Not for

  • Buyers who want the highest-performing single-driver model and a more durable cable
  • Listeners who want a multi-driver or crossover-based design, which neither model offers
  • Anyone who has not confirmed they are comfortable with a deep-sealing in-ear fit