Just as an FYI you can buy adapters that increase impedance on your headphones very cheaply on eBay. If you are looking to change sensitivity without changing i

Just as an FYI you can buy adapters that increase impedance on your headphones very cheaply on eBay. If you are looking to change sensitivity without changing impedance (which has some effects on sound signature), iFi makes the “Ear Buddy” and “iEMatch” products that are a bit more expensive, but do what they claim on the tin.