But there is a wireless headphone. And that's what he can not, in spite of less interference in the environment after only 3 meters by a thin wooden wall failures. After about 5 meters with the door open complete demolition. If you read the reviews on other sites, not an isolated case. Unfortunately Sennheiser position refuses to refer to the apparent lack of received power.
Conclusion: Good middle class headphones, in its actual discipline is not recommended as a wireless device.