The first thing you need to do is to make sure that the manufacturer of the headphone exists in the database.
To do this, please go to Database -> Manufacturers, or click here.
If it doesn't exist, please see how to add a manufacturer.
To find the "add headphone" page, go to Database -> Add, and select Add headphone, or click here
You will be presented with this page. The first action you must now take, is to select the manufacturer of the headphone in the manufacturer select.
Next, you must add the name of the headphone.
Before adding a headphone to the database, please verify that it doesn't exist under some different spelling already
To do this, go to Database -> Headphones, or click here.