It’s really important for musicians, singers and also music producers to be able to communicate and talk about music at a deeper level. Know what is a scale, a chord and what are intervals allow a more effective communication that means achieving high results in studio.
Online there are 100s of tools that can help us learning or even just refreshing some basic knowledge in music theory.
One that I feel like suggesting to use is MUSICTHEORY.NET a well put together website with a series of basic lessons that really help you learn.
Watch this video to learn the basic of music theory in half an hour.