Abstract

A significant barrier to extending research into the link between infrasound and apparitional experiences is the high cost of monitoring equipment. This paper is offered in response to requests from researchers looking for a method of measuring infrasound within a reasonable budget. It provides the construction details for a filter-set, which can be used in combination with a commercially available sound level meter. The latter is operated slightly outside its intended parameters to produce what is described as the equivalent of a litmus test for infrasound. Operating thus is clearly a risk and no absolute guarantee of success can be given. However, using this meter saves so much time and money that it was felt warranted. As part of the development process three units were built and four meters tested. Their performance compares very well with devices costing up to twenty times that invested and they are now entering use in the field. Some prior experience of electronic circuit construction is assumed.