Sennheiser is using CES 2012 to announce several additions to its line of high-end audiophile headphones. We popped by the stand to check them out.

The HD 25 Amperior set is an upgrade to Sennheiser's HD 25, a DJ-focused pair released two years ago. The company has reduced the impedance from 30 ohms to 18 ohms - Sennheiser says this is to improve performance with portable players - and added an in-line mic and smart remote that's compatible with iOS devices. It's also added an aluminium finish.

The Amperior headphones have a frequency response of 16-22,000Hz and are slated for a March launch in both the US and Europe. They have a manufacturer's recommended price of $349.95.

Sennheiser HD 25 Amperior

Moving up the scale to $549.95, the RS 220 are a wireless set that (in theory) don't compromise on audio quality. The idea is that the signal isn't compressed during transmission - it's sent over 2.4GHz wireless rather than Bluetooth.

"The output signal is spread to a width of 22MHz by means of a specified bit sequence. If interference occurs at one point within this frequency range, the output signal experiences no interference as the data is transmitted with redundancy," said company engineer Axel Grell.

The RS 220s have a frequency response of 19-21,000Hz and a maximum capacity of 106dB. The wireless has a maximum range of 100m between the headphones and the transmitter.

Sennheiser RS 220

Sennheiser RS 220

Finally - and raising the bar to an audiophile-only 699 euros - we come to the HD 700. In fact that price represents something of a reduction compared to the top-end HD 800 headphones these are modelled on; these are their little brother.

The HD 700 have an open, stainless steel gauze design and an angled cup that's designed to ensure a more realistic sound. The headband, meanwhile, is constructed from multi-layer steel and plastic, which we're told reduces distortions in the sound you hear. The headphones have a 40mm Duofol transducer, and a frequency response of 10-42,000Hz.

Regardless of the theory, the HD 700 pair we tried were quite astonishingly warm, rich and realistic, not to mention wonderfully comfortable; but then, when you're paying that sort of money you'd hope so.

Sennheiser HD 700 headphones

Sennheiser HD 700 headphones