Sound calibration: Difference between revisions

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*The calibration is calculated @ 1Vrms input and depends on the distance of the speaker to the center of the subjects head.
*The calibration is calculated @ 1Vrms input and depends on the distance of the speaker to the center of the subjects head.


    Calculation:
     Calibration = mag2db(db2mag(Sens)/Vrms/Distance^2)  
     Calibration = mag2db(db2mag(Sens)/Vrms/Distance^2)  



Revision as of 12:08, 25 April 2025

Introduction

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Sensitivity of speakers

  • In all our labs we use the Cambridge Audio MINX MIN12 speaker.
  • The speaker has a specified sensitivity of 86 dB SPL (@2.83 Vrms input)
  • The calibration is calculated @ 1Vrms input and depends on the distance of the speaker to the center of the subjects head.
   Calibration = mag2db(db2mag(Sens)/Vrms/Distance^2) 
LAB Distance (m) Calibration(dB SPL) Measured (dB SPL)
TEST LAB 1 m 80 ?
AUDITORY PERCEPTION LAB 1.05 76.1 ?
AUDITORY SPHERE LAB ? ? ?
AUDITORY MOTION LAB ? ? ?
NIRS EEG LAB ? ? ?

Sensitivity of headsets

A commercial headset normally have a higher impedance than an audiological headset and therefore a higher sensitivity.

Table: impedances and sensitivity @ 1mW and @ 1V for Headphones measured @ 1 kHz

Model Impedance (Ohm) Sens@1mW (dB SPL) Sens@1V (dB SPL) Difference (dB) Audiological
AKG_K271_MKII 55 91 104 12.5 N
SENNHEISER_HD600 300 (92) 97 5.2 N
SENNHEISER_HD100 26 (94) 110 15.8 N
BEYERDYNAMIC_DT_770_PRO 80 96 (107) 11.0 N
SENNHEISER_HDA280 37 (103) 117 14.3 Y
SENNHEISER_HDA300 23 (108) 124 16.4 Y
RADIOEAR_P4492 10 (107) 127 20 Y
TELEPHONICS_TDH-39P 10 (108) 128 20 Y
  • The numbers are from the specs on the internet.
  • The numbers between brackets are calculated from the difference between the 1mW and 1V sensitivity by: Sens(1V) = Sens(1mW) + 10*log10(R/1000)