The calculator below converts headphone efficiency to sensitivity or vice versa for the specified headphones. Since headphone impedance Rphones varies with frequency and
is complex, this calculation assumes a single real (resistive) nominal impedance value (usually at 1 kHz). The output of the amplifier is modelled
as a simple series circuit with an ideal voltage source Vs in series with an internal resistance Rs. R1 and R2 are optional external series and shunt
The calculator displays the output sound pressure level (dBSPL), the corresponding RMS headphones voltage
and the headphones power dissipation. Default values for Vs and Rs are those for the Samsung Galaxy S4 SGH-I337 smartphone at full Music player volume.
Default headphone values are for typical high-sensitivity earbuds:
Enter the headphone impedance Rphones in ohms.
To convert sensitivity to efficiency, enter the sensitivity value (dBSPL / 1Vrms) and click Get Efficiency.
To convert efficiency to sensitivity, enter the efficiency value (dBSPL / 1 mW) and click Get Sensitivity.
Headphone Sensitivity / Efficiency Converter and dB SPL Calculator