Perfect 4th
The perfect 4th is an interval that spans four notes on the musical staff. It is made up of 5 semitones. For a Perfect 4th we can hear it as the space between Do and Fa in the Do Re Mi Fa So La Ti Do scale
* Note - The unison, 4th, 5th and octave are the only perfect intervals. They cannot be made major or minor.
Sing along with the recording reading the solfege words.