The Sennheiser EW-D CI1 SET (R4-9) is a complete digital wireless system engineered specifically for electric and bass guitarists, operating in the R4-9 frequency band (552 to 607 MHz). The set includes a compact bodypack transmitter with a built-in 1/4" instrument input and a single-channel rackmount receiver from the EW-DX series. This system is designed to provide musicians with complete stage freedom without the tonal compromise or reliability issues associated with inferior wireless systems or long cables. It transmits the instrument's signal with pristine 24-bit/48 kHz digital audio quality, ultra-low latency, and secure 128-bit AES encryption.

The transmitter connects directly to the guitar's output jack, features a simple control interface, and is powered by two AA batteries. The receiver boasts Intelligent Antenna Diversity for robust RF performance in challenging environments and provides both XLR and 1/4" outputs for flexible connection to amplifiers, pedalboards, or direct inputs on a mixer. By delivering a transparent, cable-like tone with absolute wireless reliability, the EW-D CI1 SET meets the demanding requirements of touring professionals and studio musicians who cannot afford signal dropouts or degraded sound quality.