"I" "D"ON'T "P"LAY "L"OUD "M"USIC "A"FTER "L"UNCH"
Well its just a Mnemonic to remember the modes in western classical music. There are seven modes and each one is nothing but a guideline or a tone-semitone pattern formula to construct a scale from any key for that matter. But to begin with and to understand how it works, let us take the C major scale ( C D E F G A B C ) and get into the types from there.
Types of MODEs
1.Ionian ( "I" )
Notes starting on C and ending on C without using any black keys in the keyboard.In other words just playing the C major scale from C to C.That is playing these notes C D E F G A B C.( A simple theoretical Equivalent in carnatic is Sankarabaranam OR the basic C major scale in western.The tone semitone pattern here is Tone-Tone-Semitone-Tone-Tone-Tone-Semitone )
2.Dorian ( "D"ont )
Notes starting on D and ending on D without using any black keys in the keyboard.
In other words just playing the C major scale but instead of playing from C to C, here we play from D to D.
That is playing these notes D E F G A B C D. ( A simple theoretical Equivalent in carnatic is Karaharapriya.
The tone semitone pattern here is Tone-Semitone-Tone-Tone-Tone-Semitone-Tone)
3.Phrygian ( "P" lay )
Notes starting on E and ending on E without using any black keys in the keyboard.
In other words just playing the C major scale but instead of playing from C to C, here we play from E to E.
That is playing these notes E F G A B C D E. ( A simple theoretical Equivalent in carnatic is Thodi.
The tone semitone pattern here is Semitone-Tone-Tone-Tone-Semitone-Tone-Tone)
4. Lydian ( "L"oud )
Notes starting on F and ending on F without using any black keys in the keyboard.
In other words just playing the C major scale but instead of playing from C to C, here we play from F to F.
That is playing these notes F G A B C D E F. ( A simple theoretical Equivalent in carnatic is Kalyani.
The tone semitone pattern here is Tone-Tone-Tone-Semitone-Tone-Tone-Semitone)
5.Mixolydian ( "M"usic )
Notes starting on G and ending on G without using any black keys in the keyboard.
In other words just playing the C major scale but instead of playing from C to C, here we play from G to G.
That is playing these notes G A B C D E F G. ( A simple theoretical Equivalent in carnatic is Harikhamboji.
The tone semitone pattern here is Tone-Tone-Semitone-Tone-Tone-Semitone-Tone )
6. Aeolian ( "A"fter )
Notes starting on A and ending on A without using any black keys in the keyboard.
In other words just playing the C major scale but instead of playing from C to C, here we play from A to A.
That is playing these notes A B C D E F G A.
( A simple theoretical Equivalent in carnatic is Natabhairavi and in western the Natural minor scale )
7. Locrian ( "L"unch )
Notes starting on B and ending on B without using any black keys in the keyboard.
In other words just playing the C major scale but instead of playing from C to C, here we play from B to B. That is playing these notes B C D E F G A B. ( A simple theoretical Equivalent in carnatic is Thodi with panchamam replaced by prathi mathyamam OR rather the dominant 5th note being flattened by a semitone. The tone semitone pattern here is Tone-Tone-Semitone-Tone-Tone-Semitone-Tone)
It is usually better to practice these 7 modes in all the twelve keys (In any preferred order chosen. It can be done using the Circle of 5th mode OR chromatic order) the melody instrument of your specialisation to get good fingering practice and understanding. This is in one way kind of similar to the so called "Graha bedham" in carnatic music. A little information below just for an illustration.
Graha Bedham
Taking a scale and changing the pitch of the scale from note to note we end up with new ragas or scales bcos the tone semitone pattern(Or the intervals between each other in sequence) keeps changing everytime we modify the tonic.
Let us take the Mohanam scale (Theoretical Equivalent of Major Pentatonic scale as in western ) The notes used are C D E G A C. This is the first set and is called as Mohanam.
If we now change the tonic from C To D yet use the same set of notes we arrive at Madhyamavathi D E G A C D
As the next step let us change the tonic from D to E
E G A C D E and the scale that we get is Hindolam
If Tonic is moved to G it becomes Suddha saveri
G A C D E G
And finally if we keep the note A as the tonic we end up with Suddha Dhanyasi. So using five notes and by just changing the tonic we get five different scales or ragas. Hope this intrigues you a little bit to try new things in addition to what you are doing on a day to day basis in terms of music learning and practice