Original (in RA) passive sonar sound level is 60 for both subs. You decreased it to 55 which is close to Seawolf level (54) without any good reasons.
In other hand passive sonar sound level is NOT always noise at 0 kts speed because there is also "propulsion factor".
This is noise comparison:
About David & Goliath:
Sturgeon long have much better and faster torpedoes (from mid 80'):
Mk48mod4 - active/passive wireguided - range
17 NM*
vs
USET-80 - active/passive (without wire guiding) range
7.3 NM*
TEST-71M - active/passive wireguided - range
8.1 NM*
(* at max speed)
Sturgeon have much better TA (definatelly not from 1971 but from late 80' or mid 90'):
maximum detection sensivity at speed 14
Akula I TA:
maximum detection sensivity at speed 8
...and you lower passive noise of both subs, so Akula havent chance to detect you at good range for SUBROC engaging.
I think in this duel - you were Goliath
Try the same in Akula I vs Sturgeon long - im sure tis will be much harder mission for you.