1st December 2014

#

**1****Extrapolate mic noise "raw score" from sensitivity + self noise?**

----

Oktava mk-012 : noise 19dba sens -35db

Earthworks M23 : noise 22dba sens -30

CAD e100s : noise 4 dba sens -30db

DPA 4041SP : noise 8dba sens -23db

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I am not trying to get an exact noise figure per se. I am trying to get a relative noise raw score, so I can compare apples with apples. I understand that the self noise will be amplified along with the signal, to the extent the sensitivity requires amplification of the signal, to unity. Unless I am missing something egregious here.

Does it basically make sense to construct a raw score (crude as this may look) like this:

----

(Oktava) (19db of self-noise) + (35db of gain needed to unity) =

(Earthworks) 22db + 30db =

(CAD) 4db + 30db =

(DPA) 8db + 23db =

----

With a low score, obviously, meaning lower overall noise. Or am I missing something logarithmic in the math? As in, 22db is not ten percent more noise than 20db, and 30db of gain is not double 15db of gain? Therefore the "15db" in (30db vs 45db) not equal (15db vs 30db). so.....

If it is that simple, I don't know why this isn't used. Anyway, it's useful to me. If only all the world's mics were in a spreadsheet & I could apply this formula.

Oktava mk-012 : noise 19dba sens -35db

Earthworks M23 : noise 22dba sens -30

CAD e100s : noise 4 dba sens -30db

DPA 4041SP : noise 8dba sens -23db

----

I am not trying to get an exact noise figure per se. I am trying to get a relative noise raw score, so I can compare apples with apples. I understand that the self noise will be amplified along with the signal, to the extent the sensitivity requires amplification of the signal, to unity. Unless I am missing something egregious here.

Does it basically make sense to construct a raw score (crude as this may look) like this:

----

(Oktava) (19db of self-noise) + (35db of gain needed to unity) =

**54**(Earthworks) 22db + 30db =

**52**(CAD) 4db + 30db =

**34**(DPA) 8db + 23db =

**31**----

With a low score, obviously, meaning lower overall noise. Or am I missing something logarithmic in the math? As in, 22db is not ten percent more noise than 20db, and 30db of gain is not double 15db of gain? Therefore the "15db" in (30db vs 45db) not equal (15db vs 30db). so.....

If it is that simple, I don't know why this isn't used. Anyway, it's useful to me. If only all the world's mics were in a spreadsheet & I could apply this formula.