Many interval ear training resources can be found online, where you can test and train yourself with hearing musical intervals to develop relative pitch.
However, you will often find these resources to be slow, clunky, and difficult to customize your ear training session.
This interval ear training resource is not like that at all!
Its user interface makes it easy to select the intervals you want to focus on. It responds quickly, provides notation, and best of all it’s free online.
Interval Ear Training, A Foundation For Hearing Chords
If you want to develop relative pitch and start hearing chords, master the skill of hearing your basic musical intervals.
This will set you up with a foundation that makes hearing chords that much easier.
All chords are created by a combination of basic intervals.
A few minutes of interval ear training a day is all it takes to have the foundation to unlock chords.
Train your ear to hear intervals online and visit: http://www.teoria.com/exercises/ie.php