Acoustic signature of a submarine is only known when the product finished hits the testing on sea for extended period of time and under different conditions/speed and depth its recorded and finally added to IFF Library.
In essence every material used to additions and deletion in terms of customization can vastly change teh signature print of a submarine.
Fortunately such a signature print is not there to be shared as first Kalavari undergoing sea trials as of now and hence there is no question of any acoustic signature being leaked ..
Even if suppose via different means our adversaries come to know of a band in which such submarines can be found and use complex tracking methods and algorithms, there is also another big friend of ours who protects us .. Tahts the second point...
The second point is a very beautiful phenomena in the war waters surrounding IOR (near the equator the warm waters)
View attachment 328689
thats by Admiral Vishnu Bhagwat in a telegraph newspaper report
here:
http://www.telegraphindia.com/1160825/jsp/frontpage/story_104361.jsp
Thus this is why there are additional layers of protection there... Recall a recent exercise where a US SSn versus Kilo sub in Indian exercise happened and SSN could not detect kilo. Now we can be clear that US has the most sophisticated tech in its sub and yet it could not detect kilo sub.. It tells you the potential challenges... Even though they have already got signature of Kilo subs in their library via NATO allies, yet this result.. Thus, there is much more to just the signature
The third angle is the crew and its experience +capability. Even a greenhorn with the best machine can be a fail case, but a good crew under a good leader can defy everything and yet come out on top. Sufficient to say, with kilo experience already, Scorpene crew folks would have incorporated small but important learning from training and seniors.. This will matter a lot and will provide the vital difference between winning and losing..