Keyboards, Synthesizers and Carnatic Music
Traditionally, keyboard intruments have not been suited to Carnatic music. whereas a stringed intrument like a violin, guitar or mandolin has the abilty of producing gamakas (graces, shakes and glides in particular), keyboard instruments like the piano, organ or harmonium have been deficient.
This latter group of instruments were perfect for music which involved no subtle variations on the notes and there are only a maximum of twelve notes in an octave (ie. only twelve sruthis). Futhermore, the notes on most modern keyboards are tuned to the system of equal temperament, whereby the octave or sthAyi is divided into twelve equal intervals or semi-tones not to the system of pure temperament (or just intonation) where the notes take the true frequencies according to geometrical laws like the cycle of fifths. Carnatic music, with an estimated 22 sruthis or notes in an octave, uses the pure temperament as its base, and adds extra values where required by the particular rAga (eg. in Begada or DevagAndhAri).
All this does not leave the humble keyboard in a happy state as not only are the notes straight and cannot be warped to glide on to the next note or to shake, but the whole system of tuning of a keyboard is not suited to Carnatic music. Of course, to an untrained ear, it is possible to get away with playing using a the equal temperament tuning system but even then, only some ragas will suit. Ragas like HamsanAdham, KadanakuthuhAlam and GAnamurthy sound quite good on simple keyboards. In order to imitate the gamakas, the artiste has to play adjacent notes rapidly.
By the 1980s, synthesizers were quite popular and many were equipped with a small wheel on the left of the keyboard called the pitch bender. With it, you can play a note, hold it, and with the bender actually bend the note to another note either upwards or downwards. You would have to specify the maximum amount of bend beforehand as either 1 note, 2 notes an octave, etc. With subtle use of the bender, one can also produce other gamakas like the gA in kAnada rAgam. You can also use it gently to produce the common shakes found in most rAgam-s like the Ni of Madhyamavathi. Many simpler keyboards also have the pitch bender nowadays.
Although the pitch bender is useful, it is quite difficult to use, especially while playing krithis as you require constant use of the pitch bender to provide a smooth transition from one note to the next. It is very useful, however during rAga AlApanai.
Some of the more expensive synthesizers have a feature called ‘glidemode’. This automatically glides one note to the next in a smooth manner. By having this feature constantly on, the music sounds very continuous (as it should) and the pitch bender can be used for extra effect when required. I have found by having glidemode on, I can play rAgas like Ananda Bhairavi as the gA can be made from alternating Ri & Ma, the Dha a combination of Pa-Ni and so on.
Finally, the fancy ‘synths’ (jargon for synthesizers) have programmable pitch tables. This means you can assign exact frequency values (sruthis) to each key on the synth. Thus, for ragas which use rare sruthis, you can have a pitch table preset to cater for those sruthis. The synths which have this feature will also have some preset pitch tables for various tuning systems like Indonesian, Arabic, Pythagorean, etc. My synth has one for Indian music with 22 keys preset to the 22 sruthis spanning two octaves. Being over two octaves (an octave has 12 notes, 2 x 12 = 24 so two keys are not used) makes it difficult to play. Rather I prefer to use my own pitch table for various rAgams.
With all these features, the synthsizer will start getting expensive as any synth (and heavy also) which has these features are likely to have many, many more features meant for Western music. I own an Ensoniq TS-10 which I believe costs about $US 2500. It has all the features described earlier plus a sequencer to store compositions and disk drive to store and retrieve sounds and sequences you have made.
The sound I use is a bass sort of sound - similar to a bass guitar. Some people have told me it sounds like a type of veena which is a great compliment to a keyboard instrument! (My fascination with MDR's music may have chosen me to choose this sound.) The sound is good for gamakas and glidemode. Flutes and violins are usually not suited as they are Western flutes and violins. I use a sounds called Fusion violin and bamboo flute to play kalpana swaras in turn with the usual bass sound. I can programme variations in to the sound and create different effects. Recently, I have used a bass sound but have made each key presssed sound in two octaves, similar to the effect that Sri N. Ravikiran has employed on the chitraveena. This somewhat lessens the sharp effect of the bass sound.
I am very happy with my synth. I started with a little Casiotone keyboard when I was in school and was ignorant of gamakas and sruthis. Next i moved up to a Yamaha synthesizer with a pitch bender but no glidemode and now have moved up to what I believe is the top rung of synths for Carnatic music. Unfortunately it also weighs a ton and together with the carry box weighs about 20 kg! My muscles get a workout on the way to a performance!
In summary, if you are seriously considering purchasing a synthesizer and have a bit of money to spend, go to a specialist keyboard music store (not Radio Shack, Walmart or Maceys) and askfor a synthesizer (not a electronic organ) with (a) a pitch bender, (b) glidemode and (c) programmable pitch tables. Major brands include Roland, Ensoniq and Yamaha.
Hope this is of some use and further queries on this topic are welcome to me
26/2/94 updated 8th May 97
Note: I now (2006) use a Roland V-synth