The Perfect Octave Interval
The Perfect Octave (8ve) is not a particularly common interval is songs because it's quite a jump for a voice - but you should be able to do it and learning it has many benefits.
An octave is one complete lap of The Note Circle, and the easiest way to hear one is to play an open string and then the same string at the 12th fret.
To play a Perfect 8ve, play a note on one of the thickest 2 strings, and then play a note two strings down (thinner strings) and two frets up. See the diagram below for an example.
There are a few ways to play it and anytime you cross onto or over String 2 (B string) you need to jump the top note up a fret, it's one of the quirks about the guitar tuning. There are a few ways to approach playing Octaves and some are more practically useful than others and we'll be dealing with using them all in other lessons!
There are not loads of songs that start with a Perfect Octave jump, I always like Somewhere Over The Rainbow as the one that seems easiest to me, but I have included some other options below for you too!
Dr Justin prescribes 5 minutes a day of singing a Perfect 8ve (on top of your 5 mins of Play What you Hear). So 10 minutes a day of Ear Training if you can afford it!
1. Start with playing the interval on the guitar and singing along to get used to the sound and feel of the interval. Imagine your Song Reference while you are doing so, and sing the words if it helps. If you're still struggling with singing you can always hum!
2. Play and sing a root note, then stop playing and sing the interval jump and then check it on the guitar so you're sure you are getting it right and in tune.
I would recommend at least a week singing the one interval and using shapes all over the neck so that you get familiar with it everywhere - if there are parts of the neck you find a lot harder - work more on them. Play and sing this until you feel that you can sing it from anywhere and play the interval from any note! Then move onto the next interval!