bone cond. transducer output reference

Robert Withnell rwithnel at opera.iinet.net.au
Fri Jan 19 22:14:32 EST 1996


For bone conduction ABR, the transducer output is quoted re 1 microvolt 
based on the fact that for an SLM 1 volt is equivalent to 120 dB and 
therefore 1 microvolt is equivalent to 0 dB. When calibrating using an 
artificial mastoid a correction of the order of 20 dB in respect of SLM 
measurement to account for the sensitivity of the transducer in the 
artificial mastoid is necessary. 0 dBnHL corresponds to about 35 dB force 
(re 1 microvolt).

In the USA, the imperial system means that the reference is 1 dyne, which 
is 1/100 000 Newton, whilst in the above 1 microvolt represents 1 
micronewton of force. Could someone in the USA then enlighten me as to 
how the US literature historically refers to 0 dBnHL as 35 dB force (re 1 
dyne) which would seem 20 dB too high.



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