Harmonium

Article: Harmonium Lesson 1: Introduction

Introduction
Harmonium is a keyboard, and so these lessons apply equally to the harmonium as well as to the electronic synthesizer keyboard. The important difference is that you can -- and do --play the electronic keyboard with your LEFT hand also; but for harmonium, your left hand is used in pumping the bellows to force air under pressure into the inside of the harmonium. However, this difference does not apply to us, because the lessons that follow are designed for your RIGHT hand only.
Buying a Harmonium/keyboard
An ordinary keyboard is sufficient to master all the lessons that will follow. If you already have a harmonium, you do not need to buy anything else as of now.

For solo performances, you can use a synthesizer keyboard or a harmonium, depending upon your taste, convenience and availability.

For accompaniement, harmonium traditionally suits better for accompaniement during performance of ghazals and bhajans, thumri and Indian classical music, and some other types of Indian music. For accompaniement to movie songs, and all varieties of songs not mentioned in the previous sentence, the synthesizer keyboard is the preferred choice. Of course, there are no strict rules to decide this issue. Article: Harmonium Lesson 2: The Basics

Harmonium keyboard and synthesizer keyboard are taken to mean the same thing, and are called simply the "keyboard".

Take a close look at the keyboard diagram below:

The following notations are used to describe the keys on the keyboard: For convenience, the reference note, called the tonic, or the key, or the Sa, is assumed to be the first white key, indicated in the diagram by the letter S.

Remember: any key can become a Sa; but we have assumed the first white key to be the Sa (S), for convenience and convention, simplicity and uniformity.

There are seven musical notes: Sa, indicated by S; Re, by R; Ga, by G; Ma, by m; Pa, by P; Dha, by D; and Ni, indicated by N. All these 7 notes are the white keys, as shown in the diagram. They are called shuddha (natural) swara-s (notes). In this scheme , only Ma is represented by the lower-case "m"; the rest are represented by the respective CAPITAL letters.

Out of these 7 natural notes, Sa (S) and Pa (P) are invariable: Sa and Pa do not have any lower or higher variation. The remaining notes --Re, Ga, Ma, Dha, and Ni -- each has a variation. Ma has a higher variation, called Ma teevra (sharp). It is represented by the letter "M" (CAPITAL this time), its location being as shown in the diagram. The remaining four -- Re, Ga, Dha, and Ni -- each has a lower variation, called komal (flat). They are represented respectively by the letters r, g, d, and n. Their locations on the keyboard are shown in the diagram. So, we have 12 notes from Sa through Ni, as shown under: S, r, R, g, G, m, M, P, d, D, n, N.

They are represented by the 12 keys as shown in the diagram. In the present case, where our Sa is the first white key, the natural notes are white keys, and the variable notes (the sharp and flats) are black keys.
Harmonium Lesson 3: The Saptaka

The Saptaka

On the keyboard, the area S through N is called a saptaka (an octave). There are three octaves: the madhya (middle), the mandra (lower), and the taar (higher/upper). The lower octave is situated to the left of the middle; the upper octave is situated to the right of the middle octave. Again, this is clearly shown in the diagram.
A note belonging to the middle octave has no sign when represented on the paper; for example, the P of the middle octave is represented simply as: P. The note belonging to the lower octave has an apostrophe to its LEFT. Thus, for example, the P in the lower octave is represented as: 'P. The note belonging to the higher octave has an apostrophe to its RIGHT. Thus, for example, the P in the higher octave is represented as: P'. Thus, the 36 keys represent the notes in all three octaves:

'S, 'r, 'R, 'g, 'G, 'm, 'M, 'P, 'd, 'D, 'n, 'N

S, r, R, g, G, m, M, P, d, D, n, N

S', r', R', g', G', m', M', P', d', D', n', N'.
To summarize:
§ Shuddh (natural) notes are notated as S, R, G, m, P, D, N
§ Komal (flat) notes are notated as r, g, d, n
§ Teevra (sharp) Ma is notated as M
All notes belong to madhya-saptak by default; they have no sign. Notes of mandra-saptak are preceded by ' sign, and notes of taar-saptak are succeeded by ' sign.