"voice bar" について文献をWebで探した結果を，忘備録．
http://asadl.org/jasa/resource/1/jasman/v130/i4/p2521_s7 (2013/08/02 参照)
It is usually also possible to observe an emphasized frequency below F1, which has often been called the voice bar.
The voice bar has confused phoneticians for over a century, and has often confounded efforts to measure F1.
http://clas.mq.edu.au/acoustics/speech_spectra/oral_stops.html (2013/08/02 参照)
A voice bar is a band of very low frequency voiced energy below about 200 Hz and represents those frequencies that are able to pass through the tissue of the walls of the vocal tract with minimal absorption. Higher frequencies are progressively more strongly absorbed by the tissue.
http://www.f.waseda.jp/kitahara/Spr05/LX1/notes.html (2013/08/02 参照)
voice bar: 有声閉鎖音の閉鎖による無音区間において、 低域に現れるエネルギー