The actual paper is here: http://scitation.aip.org/content/asa/journal/jasa/139/6/10.1121/1.4949544 http://scitation.aip.org/content/asa/journal/jasa/139/6/10.1

The actual paper is here: http://scitation.aip.org/content/asa/journal/jasa/139/6/10.1121/1.4949544 http://scitation.aip.org/content/asa/journal/jasa/139/6/10.1... With pictures of the apparatus.