Microphone sensitivity conversion sensitivity transfer factor - Eberhard Sengpiel sengpielaudio
microphone sensitivity at 1 kHz rating power voltage transfer factor calculator calculate calculation conversion open circuit voltage decibel decibels dB SPL 1 V/dyne/cm² microbar audio Pa air sound pressure level levels volt volts V millivolt millivolts mV dynamic condenser capacitor microphones transducer type load impedance source nominal output gain level 1 V/Pa Pascal dB dBm mv English V Pa measurement output voltage energy sound field microphone sensitivity converter power rating ratings open circuit voltage ratings rating sengpielaudio Sengpiel Berlin
Deutsche Version UK-flag s/w - sengpielaudio D-flag - sengpielaudio

• Microphone sensitivity and conversion •

Sensitivity (new): dB re 1 V/Pa ← → Transfer factor: mV/Pa

International standards have established 1 Pascal (Pa) as 94 dBSPL.
This reference point is now accepted for specifying the sensitivity of microphones.
The μbar found in some non European specifications refers to 74 dBSPL (20 dB less than 1 Pa) and
the sensitivity or the transfer factor is not expressed in the usual form of "mV/Pa" as open circuit voltage rating

Reference: 94 dBSPL ⇒ 1 pascal = 10 µbars = 10 dynes/cm2
Auditory threshold: 0 dBSPL = 0.00002 Pa = 0.0002 dyne/cm2

Fill out the respective box and click on the calculation button below. The sensitivity must be a negative dB value.

Sensitivity  dB re 1 V/Pa  |  Transfer Factor  mV/Pa
↓  |  ↓
Transfer Factor  mV/Pa  |  Sensitivity  dB re 1 V/Pa
     |   

Microphone sensitivity conversion - sengpielaudio

Sensitivity (old): dB re 1 V/dyne/cm2 ← → Transfer factor: mV/Pa

Microphone firms in the USA are partly still using the old sensitivity of "dB re 1 V/dyne/cm2"
or "dB re 1 V/µbar" (74 dBSPL) and do not show the usual form "mV/Pa".

Reference: 74 dBSPL ⇒ 1 dyne/cm2 = 0.1 pascal = 1 µbar
Auditory threshold: 0 dBSPL = 0.0002 dyne/cm2 = 0.00002 Pa

Fill out the respective box and click the 'calculate' bar below.
The sensitivity must be a negative dB value.

Sensitivity  dB re 1 V/dyne/cm²  |  Transfer Factor  mV/Pa
↓  |  ↓
Transfer Factor  mV/Pa  |  Sensitivity  dB re 1 V/dyne/cm²
     |   

1 pascal = 10 µbars = 10 dynes/cm2 and 1 µbar = 1 dyne/cm2 = 0.1 Pascal
1 mV/Pa = 0.1 mV/µbar or 1 mV/µbar = 10 mV/Pa

Pascal is written in English with lower-case letter beginning: We have the pascal and we have
the dyne, and the plural dynes which are microbars. A typical condenser microphone,
having 12 mV/Pa is the same as 1.2 mV/µbar; but 12 Pa are 120 µbar.
−40 dB "re 1V/Pa" equals to −60 dB "re 1V/microbar".

Note

Forget the power ratings. They have no relevance to microphones. The term "dB SPL" is a measurement
of Sound "Pressure" Level (SPL) which is the force per area that acoustical sound waves apply to air
particles. Microphones are sensors in the soundfield which deliver an analogous voltage. Microphones
measure sound pressure, or sometimes they may measure the particle velocity, but they never measure
sound intensity directly. Intensity stereo is an unfortunate linguistic misnomer which has come to mean the
recording of stereophonic signals that are distinguished only by level differences. In stereo the level
differences have been called "intensity" differences, but sound intensity is a specifically defined quantity
and cannot be sensed by a simple microphone, nor would it be valuable in music recording if it could
"Intensity" stereophony is a misnomer and is better called level difference stereophony. Ears are
directly only sensitive to sound pressure, like microphones. Forget both intensity and the power.
A studio microphone is never attached to a load equal to its own internal resistance. The load
resistor (impedance) should always to be at least ten times greater than the internal source
resistor of the microphone (open circuit). Here only voltage is important and not the power.

Notice: The output voltage of a microphone is proportional to the incident sound pressure.

To obtain the microphone maximum output level in dBu, find your microphone's sensitivity rating on
the left side and then move right until you are directly below your microphone's maximum SPL rating.
As an example, for a microphone with a sensitivity rating of 20 mV/Pa and a max SPL equal to 130 dB.

Table 1 tells us that the maximum output voltage is +4 dBu. You now have what you need to compare
preamps regarding maximum input level.

Maximum Output Level

Microphone Dynamic Range Calculation

Enter any TWO of the following values, then press the calculate button.
The missing value will be calculated. The 10 μbar = 94 dBSPL rating is used here.

Max. SPL, e.g. 138 = dB SPL
Self noise, e.g. 16 = dB
Dynamic range = dB
  --------------------  
S/N ratio re 94 dB SPL = dB
 

Self-noise may be entered using any weighting factor (A, CCIR 468 etc)
but the dynamic range will be predicated by that weighting.
"S/N re 94 dB SPL" is 94 dB minus self noise.
The max. SPL for less than 0.5% THD should be used. If you find values for 1 % THD,
then do a 6 dB subtraction, for a more correct comparison.

back weiter Google weiter home Start