Shruti Bheda must be employed only when it occurs spontaneously while practising or performing. The beauty of shruti bheda lies in curiosity, where the artiste, as well as the rasika (listener), traverses on a path that is unbeknownst to both and eventually converges at a point where there is a manifestation of a wonderful design idea that is aesthetically coherent with the prevailing scheme of things — in this context, the underlying raga that is being rendered. For example, it is like adding milk to water which naturally blends with each other; however, adding oil to water will cause itself to float on the surface making it distinctly distinguishable and conspicuous in two separate forms.
Unfortunately, many a time, this exercise turns out to be serving exactly the opposite of what is mentioned above. Under the guise of introducing something unique, a reductionist approach is applied by the artiste(s) via parroting a rehearsed pattern that may be quite difficult and complex to shift the base scale from one shruti to the other, but it need not necessarily sound amenable to the ears. At times it could even make the experience jarring and uncomfortable for the rasika to sit through till the artiste reverts to the original scale. It could be intellectually stimulating to a few, but the novelty is lost, simply because the inherent endeavour is not discovery, rather it’s just reproduction of a practised version to showcase one’s own virtuosity. To me, it appeals to be a very amusing idea when people approach shruti-bheda from an academic standpoint. For the uninitiated, shruti-bheda is simply shifting the base scale of a given raga from one position to a different position. In Hindustani music, it is called Murchhana. For example, I will take Hindolam or Malkauns, a commonly identifiable & known rAga to both Carnatic & Hindustani music lovers. It is a pentatonic/audava raga as shown in the picture below:
Aarohana/ascendance as: Sa G2 M1 D1 N2 Sa and avarohana/descendance as: Sa N2 D1 M1 G2 Sa.
Now, we will shift the base scale / Adhaara Shruti from Sa to G2
So in the above example, the position of Sa is transposed to G2 and ends at G2. This means G2 becomes the base Sa. Hence, by shifting the base note Sa to G2 with the same arohana (G2 M1 D1 N2 Sa G2) and avarohana (G2 Sa N2 D2 M1 G2) results in an entirely different raga named Mohanam or Bhoopali with a transposed scale as Sa R2 G3 Pa D2 Sa & vice-versa Sa D2 Pa G3 R2 Sa. Although the swara pattern is the same, the outcome is different!
For more clarity, we will compare it on a chromatic scale.
The base C which was erstwhile our Sa which shifts to D# So the observation here is, if all this effort of shifting bases is to present a different raga intertwined in the same scale, might as well render that resultant raga in a separate kriti; why meddle with the existing structure?
Of course, this observation does not apply to great vaggeyakaras or musicians and consummate performers whose presentation of shruti bheda even when it is deliberate sounds absolutely natural and seamless. Figuratively, shruti-bheda conveys the idea or philosophy of Advaita (non-duality) where the swarasthanas might have changed but eventually merge with the primary theme. Here, in this video Vid. Prithvi Gandharv presents a beautiful shruti-bheda: