For your information, the Auditory list contains a very informative discussion regarding the origin of the mel scale and also the formula used above and the relationship between the mel scale and cochlea (see specifically Donald Greenwood's message on 23 July 2009). My take on the discussion is that the mel scale is problematic and to approximate an auditory scale Equivalent Rectangular Bandwidth (ERB) is better.
For a more complete and user-friendlier conversion page, please consult Hartmut Traunmüller's page at http://www.ling.su.se/staff/hartmut/umrechnung.htm
in one of the fields,
then press the "Calculate"
button to calculate the second (conversion "MEL to HZ" is also possible).
Send comments etc. to: firstname.lastname@example.orgClick here to access "Semitone conversion"-script.
Click here to access "ERB (equivalent rectangular bandwidth) conversion"-script.