TDH earphones

["Ferguson, Sarah Hargus" <safergus@xxxxxx>]

Hello all - This is a silly question, but a student asked me this in
class, and I can't seem to find it on the Internet -

What does TDH stand for? (as in, TDH-39 earphones). 

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 
Sarah Hargus Ferguson, Ph.D., CCC-A
Assistant Professor
Department of Speech-Language-Hearing: Sciences and Disorders
University of Kansas
Dole Center
1000 Sunnyside Ave., Room 3001
Lawrence, KS  66045
office: (785)864-1116
Speech Acoustics and Perception Lab: (785)864-0610
http://www.lsi.ku.edu/ipcd/FAC/Bios/FergusonBio.html