shaDvidhamArgini:
S R1 G2 M2 P D2 N2 S | S N2 D2 P M2 G2 R1 S
navanItam:
S R1 G1 M2 P D2 N2 S | S N2 D2 P M2 G1 R1 S
(difference between the above 2 is ga)
vasantavarALi:
(1) S R2 M1 P D1 S | S N2 D1 P G2 R2 S
(2) S R2 M1 P D3 N3 | N3 D3 P G2 R2 S N3
(3) S R2 M1 P D3 N3 | N3 D3 P M G1 R S N
1. I have heard MDR's pAhi rAma dhUta - it is labelled vasantavarALi but from the various aro/avaro of that raga, there is no way MDR's version is in that raga. The aro/avaro for that raga is given suddhamadhyama etc. for now

2. Now I have heard Smt. Vedavalli's rendition of g~nyAnamOsagarAdA in a concert on krithis that have undergone change. She sings it n shaDvidhamArgini - and the ga sounds closer to G1 than G2 - basically I cannot sense subhapantuvarALi like tinge - more of a varALi tinge. So close to like what navanItam would sound like.
3. On MIO there is TNS rendition of the kOTISwara Iyer's composition antaranga bhakthi in ShaDvidhamArgini - and guess what? varali tinge and no SubhapantuvarALi tinge. Again close to what navanItam would sound like
Now given all this and particular #2 (the concert's theme, the viDushi's reputation w.r.t authenticity), I am thinking that the ga of ShaDvidhamArgini is more of a G1 tinge? (like asAveri?). Of course that treads it very much into navanItam's territory.
But
4. If you listen to Hyd Bros rendition of pAhi rAmadhUta at MIO - it does seem to be in shaDvidhamArgini WITH G2 - a definite SubhapantuvarALi like tinge!!
5. There is a youtube rendition by a veena artist which also has the same melodic feel as #4. The ga is clearly G2.
And now to top things of
I found a rendition of tyAgarAja's lEmi delpa which is supposed to be in navanItam on http://www.surasa.net/music/tyagaraja-a ... index3.php (link not working for me now). And guess what? It sounds like #4 above i.e. like shaDvidhamargini scale above!
So
something which sounds like navanItam scale above is called shaDvidhamArgini (and sometimes vasantavarALi), and what sounds like shaDvidhamArgini is called navanItam :/:/
Can some pl. unravel this mystery?
Thanks
Arun