Oooohhhhh, good question!

What are your impressions?

Here are my findings (verified using two PS3s on Oceania):

1) On a medium frame, profile dampening 5 and one Advanced dampener (36dB) does not beat an advanced scanner (36dB). You still get scanned. So if the rounded dampening number is equal to the rounded scanning number, the scanner wins and you are detected.

2) On a scout suit, you need Proto scout, profile dampening 3, and one basic or militia dampener (26.96dB) to beat proto scanners (28dB). If you have the above but only profile dampening 2 (putting you at 27.54dB) you are detected, implying that 27.54dB is rounded up to 28dB.

3) As a scout with Lvl 5 precision enhancement and one advanced precision enhancer, my precision is 34.43dB, yet I can detect medium frames with profile dampening 5 who are running one complex dampener (33.75dB), implying that 34.43dB is rounded down to 34dB, and 33.75dB is rounded up to 34dB, and as the values are the same, I can detect the medium frame.

It calculates differently from what you expect. Basically it's [Base Profile] x [Reduction from Passive Skill Bonus] x [Reduction from Modules (with stacking penalties applied if applicable)].

So you get 50 db x .90 x .80, or 36dB.

Good man! Someone actually providing his test setup and results

#1 matches my previous statement, that you need to get below the scanner's precision.

#2+3 does indicate that they are rounding up/down in operation and not just UI. A test some time ago showed otherwise, but I'll take your word for it based on your tests.
(my setup was not strict enough really, hence deferring to your tests)



Small note: Due to how CCP seems to apply modifiers, they apparently sort them by size within a type, so it applies larger modifiers first, and by decreasing size. Your example is still valid, is only when you have e.g. 2 dampeners, or 2 precision enhancers (10% dampener is a 0.9 modifier, and thus larger than a 20% dampener at 0.8 modifier)

Med frame full skills need 1 complex to avoid ADV scanners and 2 complex to avoid proto at the games current state. Due to the way it calculates I believe, and have submitted as a bug that it should only require 1 complex and 1 enhanced to avoid proto, but that is NOT the case on the battle field. If you want to avoid the 28db scanner today, as a med frame you need two complex dampeners.

so you're saying 27.88 should not be scanned by a 28dB scanner?! Preposterous.

Fact:

The adv scanner will scan anything with a dB of 35.60 or higher. This has to do with how CCP calculates whole numbers: they round up at .6, so 35.6 becomes 36 and you get scanned.

An assault suit with max Dampening skill gets a bae db of 45. With a enhanced Dampener module it gets a db of 36 which is what the adv scanners scan on. Would that suit be scanned or evade it? I'm having trouble testing it because i can't know what scanner an enemy is using.