At the heart of any in-ear monitor, it’s the smallest elements that make the biggest difference, especially in the small, confined space of the ear.
There are two common formats on the market. One is borrowed from the hearing aid industry, called the balanced armature driver approach. This technology consists of an electro-magnetic motor system packed with a multitude of components and drivers. Here, a combination of several balanced armature drivers, each only able to cover a specific frequency range, work together to cover the full hearing spectrum.
The interaction of the motor system, numerous drivers, crossover points and other passive components do not always work in a cohesive way. This results in phase issues and distortions at high volumes which impairs the overall listening experience.

The alternative format follows the dynamic transducer principle. This technology solves these issues, resulting in more comfortable audio levels during long rehearsals, or recording sessions or stage performances. This 'less is more' approach, called TrueResponse® technology, uses one single high-performance dynamic transducer that covers the entire audible frequency range.

TrueResponse® provides stable, balanced sound resolution from low volumes through the maximum SPL. This unique technology allows you to enjoy exceptional sound quality with up to 100 times lower distortion than the alternative balanced armature models and requires no additional phase alignments.

The single 7mm transducer embedded into the molded enclosure enables a lighter and smaller in-ear monitor, ultimately providing a more comfortable fit. The listening experience is further enhanced due to an almost zero total harmonic distortion and true phase coherency.
When it comes to your audio experience, don’t settle for any trade-offs.
Once you try in-ear monitors with Sennheiser’s proprietary TrueResponse® technology, you’ll never want to use a different set of IEMs again.

By the nature of its design, TrueResponse® in-ear monitors are able to achieve more accurate sound pressure levels in the lower end of the audio frequency spectrum, delivering the punch you’d except from low frequency, high energy sources, such as kick drum and bass.