Measuring our microphones in home??

Hi
Can we measure S/N ratio in no laboratory conditions?
I measured all of three but values are relative.

With same gain for all on mic preamp I got different peaks:
Ela M -15db
G7 -5db
C800 -10db
When I put different gain and all of three to read -5db I recorded silence
in my vocal booth (It is not anechonic room, I hear some sounds from outside). I analyze waves in Wavelab in Global Anylysis and I saw:
Ela M -67,4db peaks, -78,6db loudness
G7 -71,2db peaks, -80,4db loudness
C800 -69,5db peaks, -78,6db loudness
On listening I have same noise on G7 and C800 but different sounding and higher noise on Ela M too different sound.
When I push mute on mic preamp I saw -92db peak.
I read about measuring with capacitor connected instead of capsule.
Duka

To measure s/n, replace the capsule with a 470pF mylar (polystyrene) capacitor. That way you won't pick up room noise.

Jakob E.

[quote author="gyraf"]To measure s/n, replace the capsule with a 470pF mylar (polystyrene) capacitor. That way you won't pick up room noise.

Jakob E.[/quote]

Thanks Jakob
What gain on preamp???
Duka

> replace the capsule with a 470pF mylar (polystyrene) capacitor

That does not measure acoustic damping noise, which is significant in most mike capsules.

The usual way to get "silence" for mike-testing is to get an old-fashioned "Pressure Cooker", a heavy cooking pot with a sealed lid. Drill out the safety valve, and put in a mike connector with LOTS of sealer. Put a slab of acoustic foam in the bottom, partly to absorb the dregs of sound that do leak in, but mostly to protect the mike and be sure it is not too close to a hard surface.

> in my vocal booth (It is not anechonic room, I hear some sounds from outside).

Then a very practical test is: seal the mike in your best room. Listen in another room. If you hear the "some sounds from outside", then the mike is quieter than the room, which is all that really matters. (It isn't really that easy: most rooms leak bass, most mikes have bass-rumble lower than most rooms, but treble hiss may be far larger than room leakage if the room is really sealed well. So you have to use judgement: is the mike noise distracting compared to the room noise, each a different shape/sound?)

Cool. idea PRR!

Don't forget to unplug the refrigerator.
And don't forget to plug it back in either!
Nice mics by the way.
:guinness:

[quote author="cjenrick"]Cool. idea PRR!

Don't forget to unplug the refrigerator.
And don't forget to plug it back in either!
Nice mics by the way.
:guinness:[/quote]

Thanks! I appreciate it!

Wish I could get some mic bodies like that... :guinness:

[quote author="Nat"]Wish I could get some mic bodies like that... :guinness:[/quote]

Nat, this is all handmade, unique and hard to build :idea:
I am not professional.
Thanks
Duka

I am surprised with poorly interest for this post :shock:

My criterion for testing my G7 for s/n was simply, can I record something very delicate and exposed in a quiet room and not have the noise floor bother me. Beyond that I'm not really concerned about a number.

They are beautiful bodies, Duka.

:thumb: :thumb: