# Tweeter sensitivity calculation

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#### Tyimo

Hi!

I have a tweeter and I don't know what is it's sensitivity. There isn't any info about it only some driver parameters:

-Z (Ohms)= 8

-Mmd (g)= 0,27

-D (cm) Diamètre émissif de la membrane = 2,95

-Sd (m2) = 0,00068

-Rcc (Ohms) = 5,25

-Bl (T.m) = 3,406

-L1 (mH) Inductance de la bobine à 1 kHz = 0,315

-Res (Ohms) = 40,9

-Fi (Hz) = Fréquence de résonance sur baffle infini 1250

-Pmax (W) = 30

Could somebody help me?

Greets:

Tyimo

#### mik

WinISD

Database editing>load parameters and it will calculate for you.

#### Tyimo

Thanks!
I did it already, but I would like to learn how to do it by my self.
What is the math and the equation.

Tyimo

#### BlueWizard

Well, the sensitivity rating on a speaker is with the speaker driven by 1 watt of power, and measure with a reference microphone at a distance of 1 meter.

Although, that only works for 8 ohm speakers. The applied signal to 8 ohms to achieve 1 watt is 2.83v. So, most speaker manufacturers test SPL at 2.83 volts regardless of actual impedance.

Most hobby users are using a cheap condenser Microphone (Panasonic?) that they have built into their own slim mic holder. This can be done for about \$25. To buy a reference mic for speaker testing would usually cost you closer to \$100.

So, apply 2.93 volts to the speaker within it's working frequency range, and measure the sound pressure level in DB at 1 meter, and you will have the rated sensitivity.

Steve/bluewizard

#### Tyimo

So, apply 2.93 volts to the speaker within it's working frequency range, and measure the sound pressure level in DB at 1 meter, and you will have the rated sensitivity.

Thanks Steve, but I don't want measure with mic.
I would like to know how the WinISD and other program calculate it from some TS parameter data.

Tyimo

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