Update (4.7.13): I shelved this app for a while since I dont use intervals much for my workouts, but I am back to using it for meditation practice.
I was thinking I had to get another meditation app with intervals, but turns out I can use this app instead because its so customizable.
I had to adjust it so that there is no warm up or cool down - and each low/high interval is 2 minutes long (that way it beeps every 2 minutes).
Works perfect, though I wish there were more sound options!
Marshmellowy about Interval Timer Pro, v2.4