The most technical comment in your article:

"Gregory Speis, a senior electronic technician at the University of New
Mexico, was sent to Mr. Ciofalo's house to conduct tests this year
after the chairman of his department received the letter forwarded from
Representative Wilson's office.

Mr. Speis said he was unable to hear the hum or detect it with his
equipment.

"I'm the kind of guy that believes in U.F.O.'s even though I've never
seen one, and I would say this is not as probable as a U.F.O.," Mr.
Speis said by phone from his office at the university."

suggests the "sound" is not acoustic.