Josh, Andy, David
After stumbling on the ringing phones in the LVEA in O2 (entry 32503) we sent this request, to find other times in h(t) that look like phone ringing glitches, to GravitySpy citizen scientists. Though it's dirty laundry airing this is a way to engage a network of many interested folks to find issues.
The reply from user @EcceruElme pointed to two similar glitches in O1/ER10/O2.
One is in Livingston at 1132398529.14 (Nov 24th 11:08 UTC - link) and looks like an ER10 instance of engaging violin mode damping while in observation ready but before SDF checks were being enforced, so ok.
One is in Hanford at 1128269436.32 which is 2015-10-07 at 16:00 during a long nice science mode lock (summary page for that day). This sounds a little like a fax machine then some bangs and a human voice through a loudspeaker and some more bangs. In the hour around that time there are also some other loud bangs. We have no idea what it could be but it happened in otherwise unbroken excellent O1 data so perhaps folks on site know what it is and if it can be (or has been) turned off.
Attachments:
- Audio file of Input Optics Microphone with no filtering.
- Spectrogram of Input Optics Mic (it was also loud in BS Mic, others in LVEA but quiet in PSL room Mics) and Strain
- OmegaScan of Strain (from GravitySpy)
I listened to this in Quicktime with the bass at max and treble at min, and it sounds like a crane being actuated on/off multiple times, which I hear in the clicking. I think the screaching is metal to metal contact as the crane moved. I hear one voice.
Listening with trebble at max and bass at min gave the same results for me.
inputoptics-mic-2015-10-07.wav sounds to me like an accidental dial into the public address system in the OSB/LVEA with feedback coming from standing near one of the overhead speakers throughout the building.
Is it possible to dial into PA systems in the VEAs? Seems that should definitely be disabled during science runs. I can see that for safety it may need to be turned on for e.g., Tuesday maintenance, but it is such an easy way to corrupt the data with rich signals that it needs to be off bounds. May I also ask that the card reader records at the time of the Event (audio event that is) be inspected, in order to determine if anyone entered the LVEA around that time?
Card reader shows no activity in the LVEA between Oct /07/2015 00:00:00 and Oct/08/2015 00:00:00 Pacific (that should be Oct/07/2015 07:00:00 to Oct/08/2015 07:00:00 UTC).
The event time is around Oct/07/2015 16:09:43 UTC.