Q concerning cSpeedNoise

[Hawk66]

Does anybody know the unit of cSpeedNoise in the database (Thrust dialog in DWEdit)?

Or to say it in other word, what does a cSpeedNoise of 21 for example means?

Thanks.

[Molon Labe]

If memory serves, that's the slope of the sound-speed relationship. So the unit would be Passive Source Level per Knot. (Maybe).

[Hawk66]

Hm, when we take following example:

- noise level defined in object database: 65
- cNoise of a typical nuclear engine: 21 (ignoring cBaseNoise)

So, the main question is for me if 65 and 21 really refer to the same unit.

If 21 means the additional noise at maximum power, then it is somewhat similar to the Harpoon 3 sonar model (http://www.harpoonhq.com/harpoon3/sonar_model.html). The Harpoon 3 sonar model seems to be inferior to DW's sonar model...it just assumes that the emitted sound increases one 1 dB / knot for all units, which is rather quite simple.

But on the other hand that the total sound level at maximum speed (ignoring cavitating effects, there is an additional modifier for that) is just 1/3 more than a sub, hovering at 0 zero...seems also strange (?)

[Molon Labe]

Sorry for the late reply.

"If 21 means the additional noise at maximum power,"

I think this is correct, rather than my first guess about the slope. I think the easiest way to confirm is to look at the stock thrusts---all of the subs increased their PSLs by 10 at maximum thrust (5 for the Kilos) so if their c values are 10 and 5, then that's exactly right. Which would mean the unit is the same as the PSL unit as you said.

[Hawk66]

Originally Posted by Molon Labe

Sorry for the late reply.

"If 21 means the additional noise at maximum power,"

I think this is correct, rather than my first guess about the slope. I think the easiest way to confirm is to look at the stock thrusts---all of the subs increased their PSLs by 10 at maximum thrust (5 for the Kilos) so if their c values are 10 and 5, then that's exactly right. Which would mean the unit is the same as the PSL unit as you said.

Thx for the hint...will check this out...