Discover a new realm of musical expression

On stage, the IER-M9 In-ear monitor headphones authentically reproduce raw emotion and musical nuance.

Faithfully reproduce every performance

With a Penta Balanced Armature system including magnesium diaphragm super tweeter, integrated magnesium inner housing and an optimised sound path, these stage monitor headphones faithfully reproduce even the most subtle sounds and emotions.

Penta Balanced Armature system for optimal stage sound

For clean high notes, natural tones and the pure emotion behind every performance, the IER-M9 has a Penta BA system including a magnesium diaphragm super tweeter. Sony’s original T-shaped Balanced Armature directly drives the diaphragm for a more linear motion and clean, faithful high notes.

Sony's original design Balanced Armature (BA) Driver units　

The unique T-shaped Balanced Armature directly drives the diaphragm for a more linear motion and clean, faithful high notes.

Magnesium diaphragm super tweeter 

The IER-M9 super tweeter diaphragm is made of light weight and rigid magnesium alloy to deliver the fast dynamic transient of performance. The unique BA unit design also benefits from extremely low resonance thanks to high internal loss. Internal wiring is upgraded with a new silver-coated copper voice coil and gold-plated terminals, faithfully reproducing sound without sacrificing even micro signals so pitch, harmonics, and emotion are portrayed.

Audio grade film capacitor for less distortion 

Our custom audio grade film capacitor in the cross-over circuit delivers much lower distortion. The audio grade capacitor of the IER-M9 delivers fine detail sound. Plus, audio grade solder also helps minimise any loss in signal path. 

Integrated magnesium inner housing to reduce vibration

A highly rigid housing keeps the BA units firmly in place, helping to eliminate vibration and keeping sound clear without losing even the most minute detail in your sound.

Optimised sound path

A wide and short sound path made of magnesium alloy reduces frequency peaks and dips, to give a monitor sound you can rely on for critical listening accuracy.

Balanced connection available

The IER-M9 In-ear monitors come with a 4.4mm standard balanced connection cable which separates left and right sound signals completely, unlike conventional headphone cables where both channels share a ground wire. This minimises cross-talk that results in sound deterioration.

Silver-coated OFC 

Silver-coated oxygen-free copper wire minimises resistance and signal-transmission loss. The result is less sound degradation, finer detail and smoother treble sounds.

Silk braid and non-magnetic undercoat plug

The IER-M9 uses silk braid as a cable insulator. This fibre works as an absorber against vibration and prevents rustling or bumping noises when you touch the cord. The gold plating of the plug has a non-magnetic undercoat which transfers the signal preserving subtle nuances.

Detachable cable

The cable is fully detachable so you can replace it if needed, or fine tune your monitor sound through a different cable.

Pre-formed ear hanger for easy positioning

The IER-M9 In-ear headphones stably fit your ears through the universally shaped ear hanger. With firm fit and optimal housing shape, each ear bud stays in the right position.

13 variations of earbuds

Our earbuds come in thirteen variations – six triple comfort and seven hybrid silicon. So you can find a snug fit for all kinds of ear shape. Combining hard silicone rubber and specially-developed formed silicone, they perfectly match sound with stability and are comfortable to wear for long lengths of time.

Light, durable magnesium outer housing

Own the stage and the moment with the light, durable magnesium outer housing of the IER-M9 In-ear headphones. Stably fit and durable against knocks or accidents.

Stable fit

The IER-M9 are designed to stay firmly in place with a snug fit for all ear sizes. With firm fit and optimal housing shape, each earbud stays in the right position, even while moving on stage.

Designed with professionals

We developed these in-ear monitor headphones cooperating with professional musicians and live-sound engineers. Their opinions are reflected in this product.