query: What could be the source of a tapping type sound coming from my upstairs air ducts?
positive_passages.docid: 26465
positive_passages.text: How can I stop our duct work "pinging" at night?
negative_passages.docid: 111185
negative_passages.text: Sound in stirred hot fluids
negative_passages.docid: 149330
negative_passages.text: Triggering an action when a specific volume is connected
negative_passages.docid: 59567
negative_passages.text: Oscillation of air particles and speed of sound wave
negative_passages.docid: 114323
negative_passages.text: Is there a name for the kind of sounds commonly found in profanities?
negative_passages.docid: 148603
negative_passages.text: How do I stop my rim brakes making a squeaking/squealing sound?
negative_passages.docid: 114128
negative_passages.text: Sounds of supersonic objects
negative_passages.docid: 86735
negative_passages.text: Pressure inside a closed room
negative_passages.docid: 110713
negative_passages.text: How can we tell which direction sound is coming from?
negative_passages.docid: 59338
negative_passages.text: How to echo a bang!
negative_passages.docid: 38072
negative_passages.text: Is it possible to use "negative sound waves" to "cancel out" a sound to create silence?
negative_passages.docid: 31241
negative_passages.text: Extended sound of thunder
negative_passages.docid: 16295
negative_passages.text: How can standing waves be produced in an open organ pipe if the ends are open?
negative_passages.docid: 105036
negative_passages.text: Why don't I hear any sound after calling the Beep function in Windows 7?
negative_passages.docid: 66218
negative_passages.text: Distorted Cabins & Oily Sheens: What happens really when a low rumble comes?
negative_passages.docid: 12971
negative_passages.text: What is the reason for this pattern of noise in electric kettles?
negative_passages.docid: 146103
negative_passages.text: Clicking feeling when I pedal