About: http://webisa.webdatacommons.org/223412876

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Description This invention relates to sound filters and in particular to a filter to be used in a duct for obtaining significant transmission loss at low frequencies, i.e., 25 Hz to 1000 Hz, both at discrete frequencies and
http://www.w3.org/ns/prov#wasQuotedFrom	patents.com