Torpedo sound levels and enemy detection

Capt Jack Harkness · 07-31-17, 08:27 PM

It's now a commonly known bug that enemies can hear torpedoes being activated, even in their baffles, and I may have found an explanation.

Looking in weapons.txt I found that the Mk 16 emits 140 dB at all times, makes sense. The Mk 37 starts at 120 dB, also makes sense, but then jumps to a whopping 230 dB as soon as it's enabled! No wonder anyone anywhere can hear it activate. The Mk 48 similarly starts at 160 dB and jumps to 230 dB when enabled.

So I decided to look at some values that make more sense for the 37, then move to the 48. With the Mk 37 we have a 17 kt run speed and 26 kt enable speed, that's roughly a 50% increase in speed so about a 100% increase in motor power, right? So that means the sound energy from the motor doubles plus the difference in flow noise. Since sound energy increases by a factor of 2 for every 3 dB it looks like the Mk 37 enable noise should only be 123 dB. And if we use the sonar self noise factor of 1 dB loss for every knot of speed to roughly anticipate flow noise that gives us 9 dB, or 132 dB total.

Does any of that math make sense to you guys or have I been doing this all wrong?

07-31-17, 08:27 PM	#1
Capt Jack Harkness Samurai Navy Join Date: Nov 2007 Posts: 567 Downloads: 210 Uploads: 1	Torpedo sound levels and enemy detection It's now a commonly known bug that enemies can hear torpedoes being activated, even in their baffles, and I may have found an explanation. Looking in weapons.txt I found that the Mk 16 emits 140 dB at all times, makes sense. The Mk 37 starts at 120 dB, also makes sense, but then jumps to a whopping 230 dB as soon as it's enabled! No wonder anyone anywhere can hear it activate. The Mk 48 similarly starts at 160 dB and jumps to 230 dB when enabled. So I decided to look at some values that make more sense for the 37, then move to the 48. With the Mk 37 we have a 17 kt run speed and 26 kt enable speed, that's roughly a 50% increase in speed so about a 100% increase in motor power, right? So that means the sound energy from the motor doubles plus the difference in flow noise. Since sound energy increases by a factor of 2 for every 3 dB it looks like the Mk 37 enable noise should only be 123 dB. And if we use the sonar self noise factor of 1 dB loss for every knot of speed to roughly anticipate flow noise that gives us 9 dB, or 132 dB total. Does any of that math make sense to you guys or have I been doing this all wrong?