IER-M9 in-ear monitors

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 optimized 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 lightweight 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 minimize 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.

Optimized 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 0.17" standard balanced connection cable which separates left and right sound signals completely, unlike conventional headphone cables where both channels share a ground wire. This minimizes cross-talk that results in sound deterioration.

Silver-coated OFC 
Silver-coated, oxygen-free copper wire minimizes 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 fiber 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.

Preformed 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 earbud 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. Stable 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 a 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.