That might be dependent on ambient sound types and quality. Test in a location with minimal ambient sound levels and minimum ambient sound content. A quiet bedroom, for example. If you live near power lines it might be worth trying in someone else's quiet room.
Since it's only the right bud it might have dirt in the microphone. Unless you are familiar with cleaning electronic audio devices I wouldn't recommend trying but there may be some obvious dirt coverage that can be removed with a clean, dry lens cleaning cloth.
You could try adjusting any EQ settings to see if it varies with them and tune it out with EQ.
You might be best having them serviced if the problem persists in a quiet, non-volatile sound environment and EQ can't help.
