balancedarmature

Balanced armature is a type of miniature electroacoustic transducer widely used in hearing aids and in-ear monitors. It consists of a small, rigid armature attached to a flexible diaphragm and suspended within a magnetic gap. When electrical current flows through a coil in the magnetic circuit, magnetic forces move the armature, which in turn drives the diaphragm to produce sound. The “balanced” in the name refers to the arrangement of the magnetic system and armature that balances forces to reduce movement of the housing and improve sensitivity and linearity in a compact form.

Construction and operation typically involve a sealed cavity behind the diaphragm, which acts as a spring to control movement. The armature’s motion produces sound by pushing and pulling on the diaphragm and the surrounding air. In practice, many devices use multiple balanced armature drivers in a single housing, each tuned to a different portion of the spectrum, with crossovers guiding specific frequency ranges to the appropriate driver. This approach is common in high-end in-ear monitors, where separate drivers handle bass, mids, and treble.

Advantages and limitations: Balanced armature drivers are compact, efficient, and capable of high sensitivity and detailed mid-to-high frequency performance. They can be very linear and fast, yielding clear articulation. However, a single BA driver often has limited low-frequency output, and achieving strong bass usually requires multiple drivers, careful enclosure tuning, and crossover design. They also tend to be more expensive and can be sensitive to fit and impedance matching, making precise tuning important for consistent sound.