One of the most glaring misconception about Indian or Hindustani Classical Music stems from its nomenclature. In Indian languages, classical music is referred to as "Shastriya" (शास्त्रिय संगीत) that literally translates to "Scientific" music. There lies the root cause of the misconceptions .. a misnomer as Scientific (shastriya) instead of being called "Abhijaat" (अभिजात) that correctly translates to "Classical" in real sense. This has previously been referred to in my earlier blog post here.
One more issue is that, classical music is not for masses. The music of masses is generally rhythm based, with a catchy melody, called folk , pop or in India the typical "Bollywood" music. These types of light musical compositions may have their root of tunes and rhythm in the classical music, but they need to be referred to as light music or popular music (pop). This fact has to be understood very clearly before any discussion on Indian or Hindustani classical music.
There is a general trend in India, of mentioning that song "xyz" from film "pqr" is based on some "abc" raag. This kind of over simplification has corrupted the beauty of classical music. A song is NEVER based on a raag. The most one can really say is that a song "xyz" is based on a tune or melody (धून ) that is used in a particular bandish of "abc" raag ... Nothing beyond that !
To further clarify , a raag has many dimensions and hence , many bandishes are composed to various melodies/tunes (धून) and rhythmic patterns (ताल) to elaborate and express that particular raag.
In this era of Whatsapp, one often finds posts of amateur fans of classical music, making lists of songs in particular raag etc... and that is fine for a student of music to recognize common musical patterns in the song and raag. It is a great way of learning music from what is known to the unknown. It does help in consolidating the key phrases of the raag that occur in the popular music and in associating to a particular named raag.
Coming back to the point of discussion : Raagdaari is a way of elaborating and expressing a raag through Khyaal. Which in turn uses a Bandish, set in a particular tune/melody (धून) and rhythmic pattern (ताल) to express one or more of the multiple facets of a particular raag.
A raag is simply a set of rules for using the set of notes. Expression of raag is called raagdaari. Often an analogy is given for raagdaari sangit to painting on a canvas.
The frame of the canvas is like the set of rules of the particular raag. Set of Colours , brushes and their strokes are tools for elaborating that particular bandish, over the canvas of the raag. This mode of expression is called raagdaari. This live "process of painting" is enjoyed by the painter(s) and the audience.
One important reason for the "classical" ness of the Indian Classical Music is this lively interaction between audience and performers that induces spontaneous improvisations. The other critical part of raagdaari , in Khyaal form, is the poetry of the bandish used in elaborating a raag. These words of poetry set to a specific melody (धून ), rhythmic patterns, tempo and modulations of sound, go beyond the literal meaning of the words of those lyrics of bandish, conveying a philosophy/thought / image ,that makes the listener "think" (ख्याल ) and enjoy the beauty of music, often fantasizing and philosophical pondering of situations in worldly living, opening up the mind for a blissful experience to the connoisseurs.
Hence Khyaal or Khayal gayaki of raagdaari , is intense , broader and illuminates mind of listeners through a "thought" that leaves for broader imagination and thinking , often philosophical in nature in tune with the subtle "Bhaav" or "Ras" of the raag !
Here is a related post on Khyaal/Khayal .. a poetic tweet.