Short answer
Dynamic (DD): a tiny cone, good at bass, common in budget sets. Balanced armature (BA): a small reed in a box, efficient in mids and treble. Hybrid: dynamic for bass plus BAs for the rest. Planar magnetic: a thin film between magnets, often praised for speed and detail. None is best by itself; tuning and fit matter more than driver type or count.
The four types
Driver types at a glance
| Type | How it works | Tends to | Examples |
|---|---|---|---|
| Dynamic (DD) | A diaphragm cone pushed by a voice coil in a magnetic field, like a tiny speaker | Natural bass, simple to tune; the budget default | Moondrop Chu II, 7Hz Zero:2, Sennheiser IE 200 |
| Balanced armature (BA) | A small reed balanced between magnets moves a diaphragm inside a sealed box | Efficient, small, precise in mids and treble | Westone Pro X10 (single BA), Shure SE846 Gen 2 (four BA) |
| Hybrid | Dynamic driver for bass plus one or more BAs, split by a crossover or tubes | Combines DD bass with BA detail; integration varies | Truthear Hexa (1DD + 3BA), KZ ZS10 Pro (1DD + 4BA), Moondrop Blessing 3 (2DD + 4BA) |
| Planar magnetic | A thin film with a printed conductor between magnet arrays | Fast, detailed; often lower sensitivity | Letshuoer S12 Pro, 7Hz Timeless II |
Dynamic drivers
The most common driver in budget IEMs. A single good dynamic driver can cover the whole range, which is why sets like the Moondrop Chu II and 7Hz Zero:2 manage balanced tunings at low prices. Makers market diaphragm materials heavily (beryllium coatings, LCP, titanium); treat those as maker claims and judge by independent measurements.
Balanced armatures
A BA is a tiny motor in a box. It is efficient and small enough that makers stack several in one shell, each covering part of the range. Pro monitors use them a lot: the Shure SE846 Gen 2 uses four, and the Westone Pro X10 uses one.
Hybrids
Hybrids try to get dynamic bass and BA detail together. The hard part is making the hand-off between drivers seamless. The Truthear Hexa (1DD + 3BA) is often praised for imaging; the Moondrop Blessing 3 uses two dynamic drivers for bass and four BAs.
Planar magnetic
A planar spreads the drive force across a thin film, so the whole surface moves together. The Letshuoer S12 Pro (14.8 mm) and 7Hz Timeless II (14.5 mm) are popular examples. Their sensitivity tends to be lower, so check that your phone or dongle can drive them to a comfortable level. Do IEMs need a DAC?
Why tuning beats driver count
What reaches your ear is a frequency response shaped by drivers, tubes, filters, the shell and your tips. Harman researchers found that listeners’ preference for in-ear headphones could be predicted from how closely the response matched their target curve (AES 2017), with groups of listeners wanting more or less bass (AES 2019). Nothing in that model counts drivers.
Curves on this site are illustrative shapes drawn to explain an idea. They are not measurements of any product. For real measurements, see squig.link and Crinacle.
Diffuse field is the older reference: roughly how a flat speaker in a reverberant room measures at the eardrum, which includes a rise in the upper mids (SoundGuys). Harman-style targets add a bass shelf and adjust the treble based on listener preference.
Next: see how drivers show up at each price in under $50, under $100 and under $300.
Questions people ask
What does 1DD + 4BA mean?
One dynamic driver and four balanced armature drivers in each earpiece. The KZ ZS10 Pro is an example: the dynamic driver handles bass and the armatures split mids and treble.
Are more drivers better?
No. More drivers need a crossover to split the signal, and a poorly integrated multi-driver set can sound uneven. Many well regarded budget IEMs use a single dynamic driver.
Are planar IEMs worth it?
They can be. Reviewers often describe planar sets such as the Letshuoer S12 Pro and 7Hz Timeless II as fast and detailed. They are often less sensitive, so a dongle with decent output helps.
What is a BA driver good at?
Balanced armatures are small and efficient, which lets makers fit several in one shell and tune each to a range. Single-BA stage monitors such as the Westone Pro X10 are known for clear mids.
Sources
- Audiophonics, Moondrop Chu II specifications
- Hangout.Audio, 7Hz x Crinacle Zero:2 specifications
- Audio46, Shure SE846 Gen 2 listing
- MusicRadar, Westone Audio Pro X10 review
- Headphonesty, Truthear Hexa review
- Headphones.com, Moondrop Blessing 3 review
- Headfonia, Letshuoer S12 Pro review
- Headfonics, 7Hz Timeless II review
- Olive, Welti, Khonsaripour, A statistical model that predicts listeners’ preference ratings of in-ear headphones, AES Convention 143 (2017)
- Olive, Welti, Khonsaripour, Segmentation of listeners based on their preferred headphone sound quality profiles, AES Convention 146 (2019)
- squig.link documentation (community IEM measurement database)
- Crinacle’s IEM ranking list (Head-Fi thread)
- SoundGuys, The house curve: how we make our target headphone responses
Last reviewed October 12, 2026. Models, versions and listings change; check the product details before you buy, and keep the volume sensible.