Strong contenders in the struggle for freedom from cables, the Sennheiser RS 110 II and RS 120 II wireless headphones have much in common in both design and performance, with the major difference being in battery type and life, resulting in comparable, but slightly different price points.
Both the RS 110 II and RS 120 II are of supra-aural design, an open headphone type made to rest on the ears. While this design is generally more comfortable to wear for extended times, sound leaks outward from the headphone cups and inward from the outside world. This is an advantage if you want to remain aware of your surroundings but a drawback for privacy and disturbing others. Both models weigh just over half a pound with batteries installed.
The transmitter bases for both models use power converters that plug into wall outlets and supply 9-volt direct current to the base. Analog audio sources connect to the transmitters by either a 1/8-inch or 1/4-inch stereo phone jack. The RS 110 II ships with a 1/4-inch adapter, while the higher priced RS 120 II includes both an RCA-to-1/8-inch adapter and a 1/8-inch-to-1/4-inch adapter. These or other common adapters permit either model to connect with a variety of audio sources, such as TVs, home stereos and personal MP3 players.
The RF receiver in each model's headset uses two AAA batteries for power. The RS 100 II takes regular batteries, while the RS 120 II uses rechargeable batteries. The base for the RS 120 II has a cradle to store the headset, and recharging takes place automatically when the headset is on the base. The RS 110 II operates approximately 22 hours on a set of batteries, while the RS 120 II lasts 20 hours on a single charge.
Using the Headphones
When you turn on the audio source connected to either model's transmitter base, the base turns itself on and begins broadcasting. Switch on the headphones by way of the power switch on the front of the right ear cup. Volume and fine-tuning dials are on the left ear cup. If you experience radio interference in the form of static, adjust the tuning dial. The base unit has three frequency selections accessible by a switch at the bottom of the front face. Select a different setting and readjust the tuning dial for best performance.